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By Patrick Holford

Life is a balancing act between making energy by combusting glucose or ketones with oxygen, which generates ‘oxidant’ exhaust fumes and dealing with these ‘oxidant fumes’ which harm the body.

Skin goes crinkly, age spots develop all due to oxidation. That’s what makes apples go brown, leaves change colour and iron rust. In the end, we lose, which is why all oxygen-based life forms have a finite life – and why your brain and body do inevitably age.

However, you can not only add years to your life, but also life to your years by improving your intake of antioxidants and polyphenols found in whole foods, fruits, vegetables and herbs and spices. A study in Finland and Sweden compared those with a ‘healthy’ versus ‘unhealthy’ diet in mid-life for future risk of developing Alzheimer’s disease and dementia 14 years later (1). Those who ate the healthiest diet had an 86-90% decreased risk of developing dementia and a 90-92% decreased risk of developing Alzheimer’s disease. Some of the benefit comes from low sugar diets, high in omega-3 and B vitamins and some from foods high in antioxidants and polyphenols which we will focus on here.

Your intake of these versus your intake and generation of oxidants, for example from smoking and pollution, is a major determinant of brain health. An illustration of this is the fact that both smoking and pollution exposure increase risk of cognitive decline and dementia, while vitamin C, which is the antioxidant par excellence, reduces risk.

(This is why we have developed our brand new Glutathione at home blood test – the first of its kind where you can accurately test your antioxidant status from home and support our further research into this important area. You can find out more and pre order the test here )

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Oxidants vs antioxidants – moving the balance in your favour

Smoking increases risk of Alzheimer’s just as much as having low B vitamin or omega-3 status, according to the US National Institute of health’s analysis (2). Smoking is something a person can easily change. Air pollution, for many, is not. It is measured in the amount of particulate matter (PMs) and people living in polluted cities are exposed to more. A study of women living in cities in the US found that those exceeding the ‘safe’ levels (greater than 12 μg/m3) had ‘increased the risks for global cognitive decline and all-cause dementia respectively by 81% and 92%’. (3)

While you may not be able to change where you live, can you mitigate the effects of pollution? The answer is yes – in two ways. Firstly, by increasing your intake of antioxidants and also by improving your B vitamin status since the body detoxifies many toxins, including toxic metals from lead to mercury, by methylation. A similar study to the one above found that residing in locations with PM exposure above the safe level was associated with a higher risk of dementia but only among people with lower intakes of the homocysteine lowering B vitamins (B6, folate, b12) (4). ‘Vitamin C in the diet or taken as supplements might help’ concludes another.(5)

Smokers need at least twice as much vitamin C as non-smokers just to have basic vitamin C levels in their blood (serum). Men do worse than women. Even with an intake of 200mg a day they do not achieve this basic blood level, which is already two to three times the recommended dietary intake and what you’d get in four oranges (6). It is certainly wise for any smoker to supplement vitamin C, perhaps adding 50mg per cigarette – 500mg if you smoke 10 a day, although there is a good case for everyone to supplement 1,000mg a day, or 2,000mg a day if over 50.

Nature always provides a solution to help us with our evolution. It seems obvious to me we need vitamin C to combat excessive pollution.

Vitamin C is a keystone nutrient as far as swinging the antioxidant equation in your favour. It’s made in all living things, from animals to plants, including yeasts and funghi. It’s probably been the essential ‘exhaust recycler’ of all oxygen-based lifeforms. Production is even activated when oxidants are sensed. Animals also make more when stressed or exposed to viruses. Us humans, and all other primates, are one of very few species who can’t make it. The first non-vitamin C making animal to be discovered was the guinea pig. That’s how it became the ‘guinea pig’ for research since, like us, it’s dependent every second of every day on vitamin C from diet. Bats, a few birds and the teleost family of fish have also lost the ability to make vitamin C. 

You’ll see in this figure below and from watching the film above, that vitamin C disarms water-based oxidants, such as smoke, and vitamin E disarms fat-based oxidants such as burnt fat. Then, there are other key antioxidant team players that help to neutralise the reactive oxidants that damage our brain and body.

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Your best bet is probably to both eat a diet with a broad spectrum of antioxidants and also supplement them. The older you are the more you are likely to need. Key antioxidants are:

Vitamin A, C and E – associated with reducing Alzheimer’s risk
Lipoic acid (7) – protects the memory-friendly neurotransmitter acetylcholine and dampens down brain oxidation and inflammation)
Glutathione (8) or N-acetyl Cysteine (NAC)(9) – protects the brain and improves methylation thus having potential in dementia prevention.
Co-enzyme Q10 – protects the mitochondria in the brain from oxidative stress (10)
Resveratrol – resveratrol has antioxidant, anti-inflammatory and neuroprotective properties and prevents hippocampal brain damage. (11)

It doesn’t really make a lot of sense to supplement one without the others.

Individually, their impact on your brain health may be less than when combined. A study of 4,740 Cache County Utah elderly residents found that those supplementing both vitamin E and C cut their risk of developing Alzheimer’s by two thirds. Taking either cut risk by a quarter (12). A recent meta-analysis of all studies on factors that could prevent Alzheimer’s by one of our Scientific Advisory Board members – Professor Jin Tai Yu of Fudan University in Shanghai, China – shows that ‘either a high vitamin E or C intake showed a trend of attenuating risk by about 26%’ making these nutrients ‘grade 1’ top level prevention risk factors (13).

All those listed above – vitamin C, E, glutathione and N-acetyl cysteine, Coenzyme Q10 and resveratrol – work together and are often found in combined antioxidant supplement formulas. There are many other team player ‘cousins’ from B vitamins to minerals such as magnesium, selenium and zinc found respectively in greens, seafood, nuts and seeds.

There are two ways to increase your intake – through food and from supplements. Foods can be measured for their ‘Total Antioxidant Capacity’ or TAC for short. It’s worked out from an equation involving eight key antioxidants from vitamin A, carotenes (think carrots), lycopenes (rich in tomatoes), lutein and zeaxanthine (rich in green vegetables), vitamin E (is nuts and seeds), but most of all vitamin C (rich in berries, broccoli, peppers and other vegetables).

(Click here to read our guidance on supplements)

The higher the TAC score of your diet the lower is your risk of cognitive and memory decline. This was the finding of a recent study of 2,716 people over age 60. The researchers measured the TAC score from their diet, splitting them into the highest to lowest quarter of TAC score, and compared this to a number of memory tests. Those in the highest quarter, eating the most antioxidant-rich foods had half the risk of decreasing memory. The higher the TAC score the better their memory function was. (14)

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Go Rainbow, ‘Mediterranean’ and eat five or more servings of fruit and vegetables a day

So, what do you need to eat and drink to preserve your memory and protect your brain?

Basically, eat a Mediterranean style ‘rainbow coloured’ diet. A Mediterranean diet has more fish, less meat and dairy, more olive oil, fruit and vegetables including tomatoes, legumes (beans and lentils) and whole grain cereals than a standard Western diet. It also includes small quantities of red wine. There are variations of this kind of diet, called the MIND diet and the DASH diet, but the core components are the same and as researchers drill down, we are learning what to eat and drink to keep your mind sharp and brain young, and how much.

The trick is to really start thinking of the colours you’re eating and gravitate for the strong colours.

Mustard and turmeric, for example, are strong yellows. Dijon mustard is great – no sugar. But if you like good old-fashioned English mustard go for it. Have a teaspoon every other day.

Add turmeric to almost any steam-fry, curry or soup. 

Bright oranges include butternut squash, sweet potato, carrots – but do buy organic. Translucent mass produced carrots are tasteless and have a higher water content, ie less actual carrot. 

Tomatoes are particularly good for you. Buy seeded, not seedless watermelons. Blend the flesh in a blender, perhaps with some ice. The black husk of the seeds drops to the bottom. The flesh of the seeds, full of essential nutrients, becomes part of this mouth-wateringly refreshing drink. Great for detox. Strawberries are a low GL fruit. Red, yellow, green and orange peppers are all rich in vitamin C.

Anything purple, magenta or blue is brilliant for you. From beetroots (eat them raw, grated into salads) to blueberries, blackberries and raspberries. Strawberries are particularly good. According to a study, part of the Rush Memory and Aging Project at Rush University, Chicago, having a higher intake cut Alzheimer’s risk by a quarter. They are high in both vitamin C and flavanoids, a high level of which were also confirmed to cut risk by a third. (15)

Strong greens are always beneficial – from spinach, kale, Brussels sprouts, broccoli, tender stem, watercress, rocket, asparagus, artichoke, green beans, peas, kohlrabi, and cauliflower (although not green).

Polyphenol power

Some of these foods are particularly rich in ‘polyphenols’ a group of health promoting molecules which also includes flavonoids, sometimes called flavanols.  Blue foods such as blueberries contain another polyphenol called anthocyanins. Tea, the cacao in chocolate, red wine, red onions, olives and all the blueish berries are rich sources of polyphenols. Many of these polyphenol rich foods act as antioxidants but they do much more than this. They improve circulation in the brain, lower blood pressure and dampen down inflammation which lies behind many conditions from depression to dementia. Once again, the principle of what’s good for the heart is good for the brain.

One of the first important studies was carried out in Norway more than a decade ago by Eha Nurk and Helga Refsum and colleagues in Norway. (16)(17) They found that:

Tea – the more you drink the better. The tea benefit has been confirmed more recently in a study in Singapore, with green tea being marginally better than black tea.(18) However, this benefit was not found in a UK Biobank study, which reported tea and coffee drinking to be associated with worsening cognition compared to abstainers. (19)

Chocolate – peaks at 10g, or about 3 pieces – and let’s say dark, 70 or more percent, thus with less sugar, is likely to be better, as sugar is a strong indicator of cognitive decline. If a chocolate is 80% cacao that means almost 20% will be sugar. More recent studies giving cocoa, a rich source of flavanols, have shown improved cognition, possibly by improving circulation.(20) This has been confirmed in a big COSMOS trial involving over 20,000 people given a cacao extract supplement rich in flavanols versus a placebo for five years. (21) The reduction in cardiovascular risk was even greater than that of a Mediterranean diet.

Wine – consumption reduces risk of cognitive decline up to an intake of 125ml a day, which is a small glass. A thorough study in the British Medical Journal in 2018, which had followed over 9,000 people over 23 years, showed that both abstinence and drinking more than 14 units of alcohol a week, which is equivalent to a medium glass of wine (2.3 units) every day, also increases risk (22). This is consistent with studies showing that a small glass of wine a day decreases risk of cardiovascular disease. Red wine, high in resveratrol is likely to be most beneficial.

All the above are rich in a polyphenol called epicatechin. Jeremy Spencer, an advisor to Food for the Brain, who is Professor of Nutritional Biochemistry and Medicine at the University of Reading, where he specialises in studying the health benefits of polyphenols and other compounds in plants, has shown that these polyphenol rich plants improve blood brain flow in specific regions of the brain that improve attention, decision-making, impulse control and emotion, thus improving overall ‘executive’ function (23). What’s more, the level of flavanols you have in your bloodstream predicts your memory. The biggest impact of increasing flavanols, was seen in the COSMOS study, in those in the lowest third for dietary intake specifically seeing improvement in aspects of memory that link to the hippocampus, that central area of the brain that degenerates in Alzheimer’s (24).

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The Best Fruit and Veg to Eat for Your Brain

Which vegetables pack the biggest punch as far as polyphenols and antioxidants are concerned and are also lower in sugar or low GL?

Taking all these factors into account – the GL, antioxidants and polyphenols these are the dozen best rated fruit and veg. But do not think of this list as finite as more and more research reveals the amazing healing power of nature’s fruits and vegetables.

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The optimal intake for brain protection is 5 to 6 servings of fruit and veg a day. 

Half a plate of a main meal counts as two. A handful of berries would count as one. So, if half your plate for two main meals is vegetables, and you had some berries with your breakfast and another piece of fresh fruit or perhaps some broccoli heads or tenderstem or carrots dipped in hummus as a snack, or half an avocado with some high polyphenol olive oil, you’ve achieved six servings.

The first step is to eat ‘whole’ foods, and especially fresh plant foods with an emphasis on those listed above that are more likely to be high in antioxidants and polyphenols. (Also see the Alzheimers Prevention Diet.) There are some nutrients such as vitamin C for which just eating whole foods doesn’t guarantee you are achieving an optimal intake and are well worth supplementing.

My advice is to supplement 500mg to 1,000mg of vitamin C twice a day and also take an antioxidant formula or antioxidant rich multivitamin containing vitamins A, C, E, lipoic acid, glutathione or NAC, resveratrol and CoQ10.

Summary

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Food for the Brain is a non-for-profit educational and research charity that offers a free Cognitive Function Test and assesses your Dementia Risk Index to be able to advise you on how to dementia-proof your diet and lifestyle.

By completing the Cognitive Function Test you are joining our grassroots research initiative to find out what really works for preventing cognitive decline. We share our ongoing research results with you to help you make brain-friendly choices.

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References

Eskelinen MH, Ngandu T, Tuomilehto J, Soininen H, Kivipelto M. Midlife healthy-diet index and late-life dementia and Alzheimer’s disease. Dement Geriatr Cogn Dis Extra. 2011 Jan;1(1):103-12. doi: 10.1159/000327518. Epub 2011 Apr 27. PMID: 22163237; PMCID: PMC3199886.
Beydoun MA, Beydoun HA, Gamaldo AA, Teel A, Zonderman AB, Wang Y. Epidemiologic studies of modifiable factors associated with cognition and dementia: systematic review and meta-analysis. BMC Public Health. 2014 Jun 24;14:643. doi: 10.1186/1471-2458-14-643. PMID: 24962204; PMCID: PMC4099157.
Cacciottolo M, Wang X, Driscoll I, Woodward N, Saffari A, Reyes J, Serre ML, Vizuete W, Sioutas C, Morgan TE, Gatz M, Chui HC, Shumaker SA, Resnick SM, Espeland MA, Finch CE, Chen JC. Particulate air pollutants, APOE alleles and their contributions to cognitive impairment in older women and to amyloidogenesis in experimental models. Transl Psychiatry. 2017 Jan 31;7(1):e1022. doi: 10.1038/tp.2016.280. PMID: 28140404; PMCID: PMC5299391.
 Chen C, Whitsel EA, Espeland MA, Snetselaar L, Hayden KM, Lamichhane AP, Serre ML, Vizuete W, Kaufman JD, Wang X, Chui HC, D’Alton ME, Chen JC, Kahe K. B vitamin intakes modify the association between particulate air pollutants and incidence of all-cause dementia: Findings from the Women’s Health Initiative Memory Study. Alzheimers Dement. 2022 Nov;18(11):2188-2198. doi: 10.1002/alz.12515. Epub 2022 Feb 1. PMID: 35103387; PMCID: PMC9339592.
 Yu JT, Xu W, Tan CC, Andrieu S, Suckling J, Evangelou E, Pan A, Zhang C, Jia J, Feng L, Kua EH, Wang YJ, Wang HF, Tan MS, Li JQ, Hou XH, Wan Y, Tan L, Mok V, Tan L, Dong Q, Touchon J, Gauthier S, Aisen PS, Vellas B. Evidence-based prevention of Alzheimer’s disease: systematic review and meta-analysis of 243 observational prospective studies and 153 randomised controlled trials. J Neurol Neurosurg Psychiatry. 2020 Nov;91(11):1201-1209. doi: 10.1136/jnnp-2019-321913. Epub 2020 Jul 20. PMID: 32690803; PMCID: PMC7569385.
 Carr AC, Lykkesfeldt J. Factors Affecting the Vitamin C Dose-Concentration Relationship: Implications for Global Vitamin C Dietary Recommendations. Nutrients. 2023 Mar 29;15(7):1657. doi: 10.3390/nu15071657. PMID: 37049497; PMCID: PMC10096887.
 A. Maczurek, et al., ‘Lipoic acid as an anti-inflammatory and neuroprotective treatment for Alzheimer’s disease’, Advance Drug Delivery Review, 2008;60(13-14):1463-70 
 Pocernich CB, Butterfield DA. Elevation of glutathione as a therapeutic strategy in Alzheimer disease. Biochim Biophys Acta. 2012 May;1822(5):625-30. doi: 10.1016/j.bbadis.2011.10.003. Epub 2011 Oct 12. PMID: 22015471; PMCID: PMC3277671.
 Hara Y, McKeehan N, Dacks PA, Fillit HM. Evaluation of the Neuroprotective Potential of N-Acetylcysteine for Prevention and Treatment of Cognitive Aging and Dementia. J Prev Alzheimers Dis. 2017;4(3):201-206. doi: 10.14283/jpad.2017.22. PMID: 29182711.
 Yang X, Zhang Y, Xu H, Luo X, Yu J, Liu J, Chang RC. Neuroprotection of Coenzyme Q10 in Neurodegenerative Diseases. Curr Top Med Chem. 2016;16(8):858-66. doi: 10.2174/1568026615666150827095252. PMID: 26311425.
 Gomes BAQ, Silva JPB, Romeiro CFR, Dos Santos SM, Rodrigues CA, Gonçalves PR, Sakai JT, Mendes PFS, Varela ELP, Monteiro MC. Neuroprotective Mechanisms of Resveratrol in Alzheimer’s Disease: Role of SIRT1. Oxid Med Cell Longev. 2018 Oct 30;2018:8152373. doi: 10.1155/2018/8152373. PMID: 30510627; PMCID: PMC6232815.
 Basambombo LL, Carmichael PH, Côté S, Laurin D. Use of Vitamin E and C Supplements for the Prevention of Cognitive Decline. Ann Pharmacother. 2017 Feb;51(2):118-124. doi: 10.1177/1060028016673072. Epub 2016 Oct 5. PMID: 27708183.
 See reference 5.
 Peng, M., Liu, Y., Jia, X. et al. Dietary Total Antioxidant Capacity and Cognitive Function in Older Adults in the United States: The NHANES 2011–2014. J Nutr Health Aging 27, 479–486 (2023). https://doi.org/10.1007/s12603-023-1934-9
 Agarwal P, Holland TM, Wang Y, Bennett DA, Morris MC. Association of Strawberries and Anthocyanidin Intake with Alzheimer’s Dementia Risk. Nutrients. 2019 Dec 14;11(12):3060. doi: 10.3390/nu11123060. PMID: 31847371; PMCID: PMC6950087.
 Nurk E, Refsum H, Drevon CA, Tell GS, Nygaard HA, Engedal K, Smith AD. Intake of flavonoid-rich wine, tea, and chocolate by elderly men and women is associated with better cognitive test performance. J Nutr. 2009 Jan;139(1):120-7. doi: 10.3945/jn.108.095182. Epub 2008 Dec 3. PMID: 19056649.
 Nurk E, Refsum H, Drevon CA, Tell GS, Nygaard HA, Engedal K, Smith AD. Cognitive performance among the elderly in relation to the intake of plant foods. The Hordaland Health Study. Br J Nutr. 2010 Oct;104(8):1190-201. doi: 10.1017/S0007114510001807. Epub 2010 Jun 16. PMID: 20550741.
 Feng L, Chong MS, Lim WS, Lee TS, Kua EH, Ng TP. Tea for Alzheimer Prevention. J Prev Alzheimers Dis. 2015;2(2):136-141. doi: 10.14283/jpad.2015.57. PMID: 29231231.
 Cornelis MC, Weintraub S, Morris MC. Caffeinated Coffee and Tea Consumption, Genetic Variation and Cognitive Function in the UK Biobank. J Nutr. 2020 Aug 1;150(8):2164-2174. doi: 10.1093/jn/nxaa147. PMID: 32495843; PMCID: PMC7398783.
 Lamport DJ, Pal D, Moutsiana C, Field DT, Williams CM, Spencer JP, Butler LT. The effect of flavanol-rich cocoa on cerebral perfusion in healthy older adults during conscious resting state: a placebo controlled, crossover, acute trial. Psychopharmacology (Berl). 2015 Sep;232(17):3227-34. doi: 10.1007/s00213-015-3972-4. Epub 2015 Jun 7. PMID: 26047963; PMCID: PMC4534492.
 Sesso HD, Manson JE, Aragaki AK, Rist PM, Johnson LG, Friedenberg G, Copeland T, Clar A, Mora S, Moorthy MV, Sarkissian A, Carrick WR, Anderson GL; COSMOS Research Group. Effect of cocoa flavanol supplementation for the prevention of cardiovascular disease events: the COcoa Supplement and Multivitamin Outcomes Study (COSMOS) randomized clinical trial. Am J Clin Nutr. 2022 Jun 7;115(6):1490-1500. doi: 10.1093/ajcn/nqac055. PMID: 35294962; PMCID: PMC9170467.
 Sabia S, Fayosse A, Dumurgier J, Dugravot A, Akbaraly T, Britton A, Kivimäki M, Singh-Manoux A. Alcohol consumption and risk of dementia: 23 year follow-up of Whitehall II cohort study. BMJ. 2018 Aug 1;362:k2927. doi: 10.1136/bmj.k2927. PMID: 30068508; PMCID: PMC6066998.
 See Professor Peremy Spencer’s presentation at the Alzheimer’s is preventable masterclass (2022); also see Spencer JP. The impact of fruit flavonoids on memory and cognition. Br J Nutr. 2010 Oct;104 Suppl 3:S40-7. doi: 10.1017/S0007114510003934. PMID: 20955649.
 Brickman AM, Yeung LK, Alschuler DM, Ottaviani JI, Kuhnle GGC, Sloan RP, Luttmann-Gibson H, Copeland T, Schroeter H, Sesso HD, Manson JE, Wall M, Small SA. Dietary flavanols restore hippocampal-dependent memory in older adults with lower diet quality and lower habitual flavanol consumption. Proc Natl Acad Sci U S A. 2023 Jun 6;120(23):e2216932120. doi: 10.1073/pnas.2216932120. Epub 2023 May 30. PMID: 37252983; PMCID: PMC10265949.

This was the title of a report in the British Medical Journal (1), pointing out that choline is an essential nutrient, much like omega-3 fats, that is vital for health and especially the brain, but not sufficiently supplied in many people’s diets, and especially those who are largely vegan.

While the body can make a little, it does not make enough and thus choline is being reclassified as an essential nutrient with an adequate intake defined as between 400mg and 520mg a day, the latter for pregnant and breast-feeding women. But these levels don’t relate to brain function. They relate to the EFSA allowed claims of “choline is needed for lipids metabolism”, “maintaining healthy liver functioning” and “reduction in homocysteine levels”. You need choline to do the right thing with cholesterol in the liver. 

But even more important is choline’s role in building and maintaining a healthy brain. A pregnant woman’s intake defines the cognitive abilities of their child. Twenty years ago we knew that pregnant rats fed choline half way through their pregnancy have more connections between brain cells, plus improved learning ability and better memory recall. Now we know it’s true for babies. In fact, a lack of choline can lead to a shrinking of a woman’s brain as the foetus robs their brain to build its own – a case of ‘Mummy I shrank your brain’. Babies are born with blood choline levels three times higher than their mother, illustrating how vital this nutrient is for building neuronal connections, which newborn babies do at a rate of up to a million new connections a second! An optimal intake for brain function is likely to be a lot higher than the 400mg recommended for adults.

Brain cells are made of a membrane containing choline (and other phospholipids) attached to the omega-3 fat DHA. Without choline the omega-3 doesn’t work. The attaching of the two depends on methylation, a process that is dependent on B vitamins, especially B12, folate and B6. Choline helps methylation and healthy methylation, indicated by low homocysteine, helps synthesize choline.

The reason the BMJ says ‘crisis’ is that more people are eating a plant-based diet and shunning eggs, fish and meat, which are the best sources of, not only choline, but also B12. There’s a tiny bit of choline in broccoli and in nuts, but not enough. An egg provides around 120mg, a 50g beef or salmon steak around 50mg. The same amount of almonds or broccoli is about 25mg. Cow’s milk has a little, but a fraction of that found in human milk. Beef liver is the richest source.

Twenty years ago I found the evidence sufficiently compelling to recommend eating an egg a day, three servings of fish and one of meat (or another portion of fish) a week, a handful of nuts, plus daily supplementation of circa 100mg, which is what I do in my ‘brain food’ formula. If you also ate a serving of broccoli a day, you’d be achieving something like 2,100mg a week, or 300mg a day – still short of daily requirements.

If you don’t eat eggs, fish or meat and don’t supplement there’s no way of getting even close. That’s why it’s time to add choline, along with omega-3 DHA and B12, to the list of nutrients that must be supplemented by those eating a vegan diet. Lecithin granules and capsules are the richest vegan source of choline, derived from soya. It will not work in building the brain, without a source of DHA which can be derived, in supplements, from algae or seaweed. 

If you want more strategies on what to eat and do to support ad upgrade your brain make sure you complete the Cognitive Function Test below to get your plan of action for improving your brain over the next 6 months.

Reference:

Derbyshire E. ‘Could we be overlooking a potential choline crisis in the United Kingdom?’ BMJ Nutrition, Prevention and Health, 2019; 0:1–4

Our brains have a dual fuel mechanism. The brains of large-brained animals like us can run on either glucose or ketones, derived from fat. If given the choice they prefer ketones. The rise in popularity in high fat ketogenic diets is partly to do with the ability of ketones to nourish and improve brain function when things go wrong, as well as weight loss benefits and the potential to reverse diabetes.

Epilepsy, for example, has been successfully treated in both children and adults with a high-fat ketogenic diet since the 1920’s often halving the frequency of fits. A recent study on people with Parkinson’s found that those placed on a high-fat diet had 41 per cent reduction in shaking, compared to 11 percent on a low-fat diet. There’s also a potential benefit in chronic fatigue syndrome.

The reason these high-fat keto diets work is that if a cell’s sugar metabolism is all messed up, a consequence of insulin resistance promoted by a high-sugar diet, then the cell struggles to get enough energy and you feel mentally and physically tired. But if, like a hybrid car, you can switch to a different fuel, ketones, then the cell comes back to life. This is especially true in struggling brain cells. When you fast, and switch to burning your body fat, the brain derives two-thirds of its energy from ketones.

Ketones are made from medium-chain triglycerides, known as MCTs. The rise in sales of MCT oil, which can be derived from palm or coconut oil. Also gaining in popularity are ketone salts and pure synthetic ketones, although these are yet to clear EU Novel Foods so are not yet available in Europe.

Fats are chains of carbon molecules and MCTs contain C6, C8, C10 and C12 oil. Of these C8 oil (called tricaprylin or caprylic acid triglyceride) makes ketones fastest. While coconut oil is 60 percent MCTs only 12 percent of MCTs is C8. That means that only 7 percent of coconut oil is C8.

The growth in bullet-proof coffee, adding a blob of coconut oil to your morning brew, is one way to up ketone levels but it’s much less effective than adding pure C8 oil. Patrick Holford’s Hybrid Latté – a coffee with carb-free almond milk, almond butter, C8 oil, cacao and cinnamon, is a step up. While coffee gives you energy like a bank loan gives you wealth it does speed up conversion to running on ketones.

Case studies with coconut oil have shown short-term beneficial effects in people with Alzheimer’s, with improved mental clarity. Two breakthrough studies in Canada, by Dr Melanie Fortier and Professor Stephen Cunnane from Sherbrooke University in Canada have established that C8 oil can be extremely helpful as an energy source for those with cognitive decline. Cunnane is an expert on fatty acid metabolism in the brain who has held the ‘Canada Research Chair on Dietary Fatty Acids and Cognitive Function during Ageing’.

Are there any downsides? A few people report abdominal or stomach discomfort. This can be minimized by building up slowly – starting with a teaspoon, then a dessert spoon, then a tablespoon, then two, then three tablespoons taken at different times of day, with food or in drinks or neat.

If glucose is petrol ketones are electricity. If your brain needs a service, switching from running on carbs to running on ketones by eating a low-carb, high-fat diet for a week, may be a good idea. It takes only 12 hours to start to run out of glucose fuel and start switching to ketones. Also good is an 18-hour carb fast – eg dinner at 6pm, lunch at 1pm. My brain stays sharp and I don’t feel hungry.

Want to know more about ketones and your brain? Then make sure you join us for our webinar: KETONES – A Key Brain Fuel During Ageing’ With Professor Stephen Cunnane

Find out more about the Ketones Webinar HERE >>>

References

 M. Nei et al., Seizure. 2014;23(6):439-42.
 M. Phillips et al., Movement Disorders 2018; 33(8):1306-1314 
 Craig C. Med Hypotheses. 2015;85(5):690-3
 C. Vandenberghe et al., Current Developments in Nutrition 2017; 1(4):e000257
 Vanderberghe et al., Can J Physiol Pharmacol. 2017 Apr;95(4):455-458.

By Research Professor Tommy Wood from the University of Washington

Most of us have two types of elderly relatives.

One of them is old – they have trouble walking, they’re in and out of the doctor’s office, and they always seem to repeat the same stories. The other type seems younger than their years they play tennis twice a week, they’re social, and they’re sharp as a tack. How can we become part of the latter group?

When it comes to aging in general and cognitive function in particular, genes obviously play a role, but did you know that lifestyle choices matter even more?[1] So, what are the top lifestyle choices to keep our brains sharp into old age?

As a neuroscientist, this is a question I often get.

Besides the obvious ones – physical activity, strength, sleep, a healthy diet, not smoking – my top tip is this: If you want to stay mentally sharp into old age, keep your brain active. In short, “use it or lose it”.

But what does “using it” look like? In this post I’ll cover some of the evidence around cognitive decline, as well as some practical take-aways for anybody wanting to improve their brain health as they get older.

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Use it or lose it

The brain is an amazing organ, and it’s more resilient and adaptable than we’ve been led to believe. I’m sure you’ve heard that adults have a fixed amount of brain cells. Then, as we get older (or every time we take a sip of wine) we “lose” some of those brain cells as part of an unstoppable decline towards dementia or Alzheimer’s disease.

But that’s not necessarily true. I like to think about the brain like I think about muscles. In order to grow our muscles, we need to provide a stimulus – like lifting weights in the gym – followed by a period of rest. The opposite also happens – if we stop going to the gym or if we stop using a limb after breaking a bone – our muscles get smaller. Most have experienced this personally, and there’s every indication that your cognitive “muscle” behaves in the same way.

How do we know this? One type of evidence is that longer education seems to reduce dementia in later life. [2]* You might think of education as early cognitive muscle building that you then benefit from throughout life. We see similar effects from other forms of early cognitive stimulus – like protection from neurodegenerative disease in people who grew up bilingual.[3]

But we’re not cognitively doomed after adolescence. One of my favourite studies looked at adults studying “The Knowledge” – memorising ~25,000 streets in central London to become a taxi driver. These participants were in their 30s or 40s, yet they saw a significant increase in the size of the hippocampus, the brain region associated with memory.[4]

We also see the opposite effect – less cognitive stimulus increases the risk of cognitive decline and dementia. This is most easily studied by looking at retirement. Multiple studies in populations across the US, China, and Europe, show that the risk of cognitive decline accelerates after retirement.[5-8] Those that retire later are protected against cognitive decline, even after considering factors that might force early retirement such as poor health. Overall, a recent meta-analysis looking at health and lifestyle factors associated with cognitive decline found that cognitive activity was the single most protective factor – halving the risk of Alzheimer’s disease.[2] This really emphasises the lesson: use it or lose it. What counts as ‘protective cognitive demand’? Doing something badly.

The evidence around retirement and cognitive decline suggests that work is where adults tend to get most of their cognitive activity. However, it’s important to unpick what constitutes cognitive activity that is protective. We may feel that our work demands a lot from our brain, but being “busy” does not necessarily benefit the brain. In fact, it’s often the opposite. Being “busy” tends to come with stress, and though stress is very personal, chronic stress is associated with an increased risk of Alzheimer’s disease.[9] What keeps us busy and stressed – sitting in meetings, reading emails, inputting data – may be time consuming, but rarely requires much brain power.

So, what constitutes protective cognitive demand? Failure.

Activities that provide the greatest cognitive stimulus involve learning and skill development. That means we’re initially bad at them and occasionally fail before we get better. This is the real sticking point for improving brain health – as adults we hate the feeling of being bad at something. Failing is, however, when the magic happens. A fascinating study looked at the brains of musicians.[10] While both professional and amateur musicians’ brains looked younger compared to non-musicians of the same age, the benefit was greatest in amateur musicians. The researchers suggested that playing music is more of a cognitive stimulus for amateurs – it’s harder, so they get more benefit. The cocktail of hormones released as we try, fail, repeat, and learn, provides the ideal environment for the brain to grow and adapt.

How to “use it”

So, how should we apply this knowledge? Below are some of the best and easiest ways to build in cognitive stimuli you can benefit from for years to come.

1 | Pick an activity that’s truly challenging
Cognitive demand requires failure, so pick something you’ll be bad at initially. What’s cognitively challenging is personal, but learning a new language is better than sudoku, building model airplanes is probably better than reading the news, and playing chess is definitely better than scrolling through Instagram. As you get better, add challenge to keep stimulating your brain.

2 | Start small and do something you enjoy
Skill development should be a lifelong process, which means it should be a routine. Start small – for instance 2 minutes a day of playing an instrument or learning a new language. Make sure your new skill is something you enjoy – that makes it easier to stick to and keep as a part of your life.

3 | Move – with a skill component
Movement has some of the best evidence on improving brain health. One of the first studies to show that the hippocampus can grow in adults of retirement age (or older) used a walking intervention – just 40 minutes of brisk walking 3x per week.[11] Other studies have showed increased brain connectivity and function in adults doing resistance training 1-2 times per week.[12] Best is movement that includes balance or motor skills: the added challenge of coordination seems to be particularly protective against cognitive decline.[13] Think yoga, dance, or even skateboarding

4 | Try a new skill that’s social
Social interaction is its own form of cognitive stimulus: social connection is protective of cognitive function, while social isolation has the opposite effect.[14] So what’s better than simply learning a new skill? Doing so with friends. Start a book club to discuss the books you read. Join a knitting circle, language group, or dance class. Volunteer for a local charity. All of these help you learn new skills, with the added benefit of social interaction.

5 | Repeat, repeat, repeat
There are no hard and fast rules about how much or how often to work on a new skill, but once a week is a good start. If it’s a class or a movement practice, maybe 1-3 times per week. If it’s something you can do on your own, you may prefer more frequent, smaller bouts of focused practice. Try using a Pomodoro timer to dig in for 20-30 minutes – a suitable time for most people to keep their undivided attention.
The key is to push right at the boundaries of what you’re capable of – with occasional failure showing that you’re at the right level of difficulty. Keep at it, and you’ll be more likely to be healthy and sharp for decades to come.

Footnote
*It’s worth noting that those who stay in education for longer also tend to be socioeconomically advantaged, but the benefit of longer education seems to hold even accounting for that.

Thank you for reading!

Food for the Brain is a non-for-profit educational and research charity that offers a free Cognitive Function Test and assesses your Dementia Risk Index to be able to advise you on how to dementia-proof your diet and lifestyle.

By completing the Cognitive Function Test you are joining our grassroots research initiative to find out what really works for preventing cognitive decline. We share our ongoing research results with you to help you make brain-friendly choices.

Please support our research by becoming a Friend of Food for the Brain.

References

Lourida I, Hannon E, Littlejohns TJ, Langa KM, Hyppönen E, Kuźma E, Llewellyn DJ. Association of Lifestyle and Genetic Risk With Incidence of Dementia. Jama. 2019;322(5):430-7. doi: 10.1001/jama.2019.9879.
Yu JT, Xu W, Tan CC, Andrieu S, Suckling J, Evangelou E, Pan A, Zhang C, Jia J, Feng L, Kua EH, Wang YJ, Wang HF, Tan MS, Li JQ, Hou XH, Wan Y, Tan L, Mok V, Tan L, Dong Q, Touchon J, Gauthier S, Aisen PS, Vellas B. Evidence-based prevention of Alzheimer’s disease: systematic review and meta-analysis of 243 observational prospective studies and 153 randomised controlled trials. J Neurol
Neurosurg Psychiatry. 2020;91(11):1201-9. Epub 2020/07/22. doi: 10.1136/jnnp-2019-321913. PubMed PMID: 32690803; PMCID: PMC7569385.
Sala A, Malpetti M, Farsad M, Lubian F, Magnani G, Frasca Polara G, Epiney JB, Abutalebi J, Assal F, Garibotto V, Perani D. Lifelong bilingualism and mechanisms of neuroprotection in Alzheimer dementia. Hum Brain Mapp. 2022;43(2):581-92. Epub 2021/11/04. doi: 10.1002/hbm.25605. PubMed PMID: 34729858; PMCID: PMC8720191.
Woollett K, Maguire EA. Acquiring “the Knowledge” of London’s layout drives structural brain changes. Current biology : CB. 2011;21(24):2109-14. Epub 2011/12/08. doi: 0.1016/j.cub.2011.11.018. PubMed PMID: 22169537.
Hale JM, Bijlsma MJ, Lorenti A. Does postponing retirement affect cognitive function? A counterfactual experiment to disentangle life course risk factors. SSM – Population Health. 2021;15:100855. doi: https://doi.org/10.1016/j.ssmph.2021.100855.
Dufouil C, Pereira E, Chêne G, Glymour MM, Alpérovitch A, Saubusse E, Risse- Fleury M, Heuls B, Salord JC, Brieu MA, Forette F. Older age at retirement is associated with decreased risk of dementia. Eur J Epidemiol. 2014;29(5):353-61. Epub 2014/05/06. doi: 10.1007/s10654-014-9906-3. PubMed PMID: 24791704.
Nikolov P, Adelman AM. Do Pension Benefits Accelerate Cognitive Decline? Evidence from Rural China. Labor: Public Policy & Regulation eJournal. 2019. Sundström A, Rönnlund M, Josefsson M. A nationwide Swedish study of age at retirement and dementia risk. Int J Geriatr Psychiatry. 2020;35(10):1243-9. Epub 2020/06/20. doi: 10.1002/gps.5363. PubMed PMID: 32557831.
Ye Y, Li J, Yuan Z. Effect of antioxidant vitamin supplementation on cardiovascular outcomes: A meta-analysis of randomized controlled trials. PloS One. 2013;8:e56803. doi:10.1371/journal.pone.0056803.
Rogenmoser L, Kernbach J, Schlaug G, Gaser C. Keeping brains young with making music. Brain Struct Funct. 2018;223(1):297-305. Epub 2017/08/18. doi: 10.1007/s00429-017-1491-2. PubMed PMID: 28815301.
Erickson KI, Voss MW, Prakash RS, Basak C, Szabo A, Chaddock L, Kim JS, Heo S, Alves H, White SM, Wojcicki TR, Mailey E, Vieira VJ, Martin SA, Pence BD, Woods JA, McAuley E, Kramer AF. Exercise training increases size of hippocampus and improves memory. Proceedings of the National Academy of Sciences. 2011;108(7):3017. doi: 10.1073/pnas.1015950108.
Herold F, Törpel A, Schega L, Müller NG. Functional and/or structural brain changes in response to resistance exercises and resistance training lead to cognitive improvements – a systematic review. Eur Rev Aging Phys Act. 2019;16:10. Epub 2019/07/25. doi: 10.1186/s11556-019-0217-2. PubMed PMID: 31333805; PMCID: PMC6617693.
Ludyga S, Gerber M, Pühse U, Looser VN, Kamijo K. Systematic review and meta- analysis investigating moderators of long-term effects of exercise on cognition in healthy individuals. Nature Human Behaviour. 2020;4(6):603-12. doi: 10.1038/s41562-020-0851-8.
Penninkilampi R, Casey AN, Singh MF, Brodaty H. The Association between Social Engagement, Loneliness, and Risk of Dementia: A Systematic Review and Meta-Analysis. J Alzheimers Dis. 2018;66(4):1619-33. Epub 2018/11/20. doi: 10.3233/jad- PubMed PMID: 30452410.

Neurons, that is brain and nerve cells, are primarily made out of what’s called ‘phosphorylated DHA’. That means the omega-3 fat DHA that is bound to a kind of fat called a phospholipid, as shown in the figure below. 

Seafood contains phosphorylated DHA but DHA supplements, whether derived from fish oil or algae, is not phosphorylated. Hence, it needs to be attached to phospholipids to work. This attachment is done by a B vitamin dependent process called methylation. 

There are several different kinds of phospholipids with strange names all starting with ‘phosphatidyl’ such as phosphatidyl choline, phosphatidyl serine, phosphatidyl inositol and phosphatidyl ethanolamine.  To a large extent these can be made from phosphatidyl choline. As a group of nutrients they are classified as ‘semi-essential’ because we can make some, but not enough for optimal health and especially optimal brain health. 

As a consequence there are moves afoot to classify choline (which can be easily attached to the ‘phosphatidyl’ part) as an essential nutrient with a recommended intake. This has come about due to the growing evidence that insufficient choline in pregnancy leads to cognitive impairment and developmental delay. This is particularly important for vegans because, like the omega-3 fatty acid DHA, there’s not much choline in plant-based foods, but there is some in foods such as quinoa, soya, beans, nuts and broccoli.

Currently an adequate intake of choline is defined as between 400mg and 520mg a day, the latter for pregnant and breast-feeding women. This is based on how much choline you need for healthy fat metabolism, liver function and reducing homocysteine levels. You also need choline to process cholesterol in the liver and brain. As you’ll see in the figure above, cholesterol is a vital brain component. But these levels don’t take into account what’s being learnt about choline’s role in brain development.. A good estimate of optimum daily choline intake would be at least 500mg and maybe double this in pregnancy. 

Most important is choline’s role in building, and maintaining, a healthy brain. A pregnant woman’s intake defines the cognitive abilities of their child. Twenty years ago we knew that pregnant rats fed choline half way through their pregnancy have more connections between brain cells, plus improved learning ability and better memory recall. Now we know it’s true for babies with several recent trials showing similar results indicating that more choline in pregnancy enhances cognitive development.

An example of this is a study which gave women in their third trimester of pregnancy either 480mg of choline or almost double this – 930mg. They then tested the babies’ information processing speed at 4,7,10 and 13 months. Not only were the babies of the mothers given the higher dose faster but also the longer the mother had been given even the lower dose the faster were the child’s reactions. The authors concluded that “even modest increases in maternal choline intake during pregnancy may produce cognitive benefits for offspring ”. Seven years later, there will still memory advantages in the children whose mother had extra choline during pregnancy.

Babies are born with blood choline levels three times higher than their mother, illustrating how vital this nutrient is for building neuronal connections, which newborn babies do at a rate of up to a million new connections a second! An optimal intake for brain function is likely to be a lot higher than the 400 to 500mg recommended for adults, and higher still in pregnancy.

Since brain cells are made of a membrane containing choline (and other phospholipids) attached to the omega-3 fat DHA, without choline the omega-3 doesn’t work. The attaching of the two depends on methylation, a process that is dependent on B vitamins, especially B12, folate and B6. Choline helps methylation and healthy methylation, indicated by a low blood level of homocysteine, helps synthesize choline. You need all three – DHA, choline and B vitamins especially B12. So, if you are lacking in DHA, or in vitamin B12, then you’ll be doubly dependent on getting enough choline.

Choline rich foods – are vegans at risk of deficiency? 

While the richest dietary sources are fish, eggs and organ meats there is significant amounts of choline in plant-based foods, notably soya as in tofu and soya milk, quinoa, nuts and seeds including flax seeds, almonds and peanuts, and cruciferous vegetables including broccoli, cauliflower and Brussels sprouts.

While, on the face of it, it does appear than vegans, especially those planning pregnancy, need to become choline focused in relation to choosing the right daily foods, and possibly supplementing, there is not yet conclusive evidence showing that vegan mothers are at risk, although it is likely that they are. One of the learnings that has come out of studies on omega-3 DHA is than vegan mothers may convert more vegan omega-3 ALA into DHA as an evolutionary imperative – not that a top up with supplementation isn’t still the recommendation. Could it be that vegan mothers make more choline if needed since it is so important for brain development? There are very few studies of vegans to know the answer to this question.

One recent study looked at choline levels in breast-milk of vegans, versus vegetarians and non-vegetarians. There was no significant difference with the author of the study concluding “This suggests that maternal plant-based diet by itself is not a risk factor for low breast-milk choline.” 

The vegan community is certainly divided on this issue. Of course, the safe or cautious position, while the science unravels, is to supplement choline during pregnancy.

What intake of choline can you achieve from a vegan diet alone? Here’s a list of the best plant-based food for choline, compared to egg and fish as a yardstick, listed in order of how much you could get in a reasonable serving*:

FOOD CHOLINE PER SERVING PER 100g

An egg (all in the yolk) 50g 113mg  226mg

Fish eg salmon (100g/3oz) 90mg 90mg

Soya milk (cup – 250g) 57mg 23mg

Shiitake mushrooms (1 cup/145g) 54mg 37mg

Soya flour 12.5g (a cake slice) 24mg 192mg

Peas (1 cup -160g) 47mg 30mg

Quinoa, raw (1/3 cup 60g) 42mg 70mg 

Beans, raw (1/3 cup – 60g) 40mg 67mg

black, white, pinto, kidney

Broccoli, cauliflower 

or sprouts (1 cup/91g) 36mg 40mg  

Tofu (half a cup-125g) 35mg  28mg

Hummus (1/2 cup) 34mg 28mg

Chickpeas (1/4 can) 33mg 33mg

Baked beans (1/4 can) 31mg 31mg

Flaxseeds (small handful) 22mg 78mg

Pistachio (small handful) 20mg 71mg

Pine nuts (small handful) 18mg 65mg

Cashews (small handful) 17mg 61mg

Wholegrain bread (2 slices – 50g) 17mg 34mg

Avocado (1/2) 14mg 28mg

Almonds 50g (small handful) 12mg 42mg

Peanuts (small handful) 12mg 42mg

Wheatgerm (tablespoon 7g) 12mg 178mg

Almonds or peanut butter (tbsp) 10mg 61mg

Source: USDA choline content database and https://nutritiondata.self.com

*Many foods have not been analysed for choline, and measurements do vary, so this is a guide rather than a definitive list.

What does this mean for your daily diet? Here’s a typical vegan daily menu aimed to maximise choline intake and how much it would give you (I’m not including all foods and recipes, just those ingredient that deliver significant amount of choline):

BREAKFAST

A cup of soya milk 57mg

Small handful of nuts or seeds 20mg

(Flax, chia, almonds etc)

LUNCH

A cup of cooked quinoa (1/3 cup raw) 43mg

A serving (100g) of either broccoli, 36mg

cauliflower or Brussels sprouts

Avocado (1/2) 14mg

SNACKS

A tablespoon of almond or peanut butter 10mg

Hummus (1/2 cup) 34mg

Two slices of wholegrain bread 17mg

DINNER

A serving of tofu (125g) or beans 35-40mg

Half a cup of shiitake mushrooms 27mg

A serving (100g) of either broccoli, 36mg

cauliflower or Brussels sprouts

TOTAL 332mg

In reality you are unlikely to achieve this every day, and it would be quite limiting on your food choices, so a realistic target would be to achieve 300mg of choline from food. If you are aiming to achieve 500mg, which is the low end of optimal – more than this may be optimal in pregnancy – that leaves a shortfall of around 200mg of choline, suggesting the need for supplementation.

The most direct source of choline is from soya-derived lecithin granules and capsules. A flat tablespoon of lecithin granules (7.5g), which has a neutral and pleasant taste and can be sprinkled on cereals, in shakes and soups or eaten as is, provides 1,500 mg of phosphatidylcholine and around 200mg (13 per cent) of choline. Some ‘high phosphatidyl choline’ lecithin, sometimes called ‘high PC lecithin’ is 18 per cent choline, thus you need less – approximately a flat dessertspoon.

One tablespoon of lecithin granules equals three 1,200mg lecithin capsules (if ‘high PC’ two capsules would suffice). We suggest that this is a sensible addition to a completely vegan diet. (If you aspire to be plant-based most, but not all of the time the addition of two eggs, or an egg and a fish serving, would achieve 500mg a day of choline.)

You can also find ‘brain food’ supplements providing a combination of different kinds of phospholipids, not just choline, but its hard to get enough choline from these if your only other food sources are plant-based foods. 

In summary, we need both omega-6 and omega-3 fats, as well as phospholipids.

Have one or two servings a day of dark green, leafy veg – especially those that grow in colder climates such a kale, broccoli, brussels sprouts, or a serving of seaweed as sources of both choline and omega-3.
Have a serving of quinoa, beans or tofu every day, if not two, for choline.
Have a dessertspoon of high PC lecithin, or two capsules of high PC lecithin granules every day. These guidelines are especially important if you are planning a pregnancy, pregnant or breast-feeding.

If you are not completely vegan the best food source for phospholipids and choline are eggs. Eat six eggs a week. The choline is in the yolk. The advice regarding omega-3 – eat three servings of fish a week, is good for choline too but it is present in all fish, not just oily fish high in omega-3 fats.

Have you taken the Cognitive Function Test to find out your Dementia Risk Index score? It’s completely FREE and you can choose to pay for the COGNITION programme afterwards if you need personalised recommendations to help you put diet and lifestyle tips into action.

Brain Fats – Seafood, Omega-3 PUFAs, Phospholipids and Vitamin D

The omega-3 fat, docosahexaenoic acid (DHA) is the most abundant PUFA in the brain, concentrated in the grey matter and, particularly at the synapses.¹ DHA is incorporated into membrane phospholipids, where it affects the properties of the membrane, for example, maintaining membrane fluidity. DHA, along with other omega-3 fats EPA, DPAn-3 and their mediators are involved in a wide variety of processes in the brain, such as making new neurons, synaptic connections and the regulation of inflammation.²

Fish, especially cold-water oily fish, contain high levels of DHA and EPA,  and epidemiological studies consistently suggest that an elevated fish intake is associated with decreased risk of neurodegenerative diseases, such as Alzheimer’s disease.³ Recent estimates suggest that worldwide many populations are currently consuming DHA and EPA at levels well below the recommendations issued by many international authorities (GOED), with and blood levels of EPA and DHA have been estimated to be low to very low for most of the world, which may increase global risk for chronic disease.⁴

Interestingly, positive associations have also been found between walnut consumption and cognitive performance.⁵ Walnuts are a source of omega-3 fat, alpha-linolenic acid (ALA) and also a range of antioxidants.

Omega-3 Supplementation and cognitive decline

DHA supplementation appears to show the greatest promise in the early stage before the onset of memory loss symptoms,¹ and at levels at or above 1000 mg per day (Ismail 2015).⁶

A study of healthy 50-75 year olds were given 2,200 mg a day of omega 3 fish oils for six months not only reported significant increase in executive function, one aspect of cognition that is a hallmark of Alzheimer’s, but also beneficial structural changes in white matter integrity and grey matter volume in the brain. The cognitive improvement correlated with blood levels of omega-3 PUFAs.⁷

A randomized, double-blind, placebo-controlled, clinical study, gave 900 mg of DHA a day for 24 weeks and reported an improvement in learning and memory function in those with age-related cognitive decline.⁸ In a further trial by the same research group, giving 2,000 mg a day of DHA or placebo to 402 people with mild to moderate Alzheimer’s disease, therefore further along the disease process, for a period of 18 months found no cognitive improvement.⁹

Phospholipids

Phospholipids, rich in eggs and seafood, are abundant in the brain. They make up the membranes of the different types of cells in the brain. These include Phosphatidylethanolamine (PE) and phosphatidylserine (PS) phosphatidylcholine (PC) and phosphatidylinositol (PI). They become attached to omega-3 DHA. (see film ‘Build Your Brain‘) Phosphatidylethanolamine (PE) and phosphatidylserine (PS) are enriched in DHA, whereas much lower levels are found in phosphatidylcholine (PC) and phosphatidylinositol (PI).³ Attaching DHA to phospholipids is a process that requires methylation, which is dependent on B vitamins.⁹ Interestingly, although DHA is typically found high in PS, levels have been found to be low in PS in post-mortem samples from Alzheimer’s disease patients.¹⁰ PS supplementation may benefit cognition in the elderly,¹¹ but as PS is highly enriched with DHA, it is currently unclear whether the potential beneficial effects of PS on cognition are due to the intact PS or DHA.  Although PC is not highly enriched in DHA, higher plasma concentrations of PC-DHA are associated with reduced risk of dementia and AD,¹² and post mortem samples from AD shows depletion of PC-DHA in grey matter.¹³

Supplementation

A number of trials have investigated the effects of providing multinutrient supplements containing a range of nutritional factors with the aim of supporting phospholipid biosynthesis. Our recent systematic review identified that omega-3 PUFAs and B vitamins as part of these multinutrient formulas confers benefits on cognition in older adults across a range of different types of measures of cognition in older adults.¹⁴ Furthermore, 12-week trial of citicoline has shown cognitive benefits in healthy older adults.¹⁵

Vitamin D

The primary source of vitamin D is exposure to sunlight. Seafood provides the most dietary vitamin D. Vitamin D deficiency increases risk of AD.^161,17,18  Supplements of vitamin D can be derived from animal or fungal sources (mushrooms and yeast). Supplementing 800iu (20mg) a day for 12 months has been shown to improve cognitive function and lessen amyloid protein markers.¹⁹

In a study in France involving 912 elderly patients followed for twelve years, a total of 177 dementia cases (124 AD) occurred: 25(OH)D deficiency was associated with a nearly three-fold increased risk of AD.²⁰

References

1.Dyall, S. C. (2015, 2015-April-21). Long-chain omega-3 fatty acids and the brain: A review of the independent and shared effects of EPA, DPA and DHA [Review]. Frontiers in Aging Neuroscience, 7(52). https://doi.org/10.3389/fnagi.2015.00052

2. Dyall, S. C., Balas, L., Bazan, N. G., Brenna, J. T., Chiang, N., da Costa Souza, F., Dalli, J., Durand, T., Galano, J. M., Lein, P. J., Serhan, C. N., & Taha, A. Y. (2022, Apr). Polyunsaturated fatty acids and fatty acid-derived lipid mediators: Recent advances in the understanding of their biosynthesis, structures, and functions. Prog Lipid Res, 86, 101165. https://doi.org/10.1016/j.plipres.2022.101165

3. Dyall SC, Michael-Titus AT. Neurological benefits of omega-3 fatty acids. Neuromolecular Med. 2008;10(4):219-35. doi: 10.1007/s12017-008-8036-z. Epub 2008 Jun 10. PMID: 18543124.

4. Stark, K. D., Van Elswyk, M. E., Higgins, M. R., Weatherford, C. A., & Salem, N., Jr. (2016, Jul). Global survey of the omega-3 fatty acids, docosahexaenoic acid and eicosapentaenoic acid in the blood stream of healthy adults. Prog Lipid Res, 63, 132-152. https://doi.org/S0163-7827(15)30033-3 [pii]10.1016/j.plipres.2016.05.001 Alzheimers Dement. 2017 Nov;13(11):1207-1216. doi: 10.1016/j.jalz.2017.03.003. Epub 2017 May 16

5. Theodore LE, Kellow NJ, McNeil EA, Close EO, Coad EG, Cardoso BR. Nut Consumption for Cognitive Performance: A Systematic Review. Adv Nutr. 2021 Jun 1;12(3):777-792. doi: 10.1093/advances/nmaa153. PMID: 33330927; PMCID: PMC8166568.

6. Ismail

7. A. Veronica Witte, Lucia Kerti, Henrike M. Hermannstädter, Jochen B. Fiebach, Stephan J. Schreiber, Jan Philipp Schuchardt, Andreas Hahn, Agnes Flöel, Long-Chain Omega-3 Fatty Acids Improve Brain Function and Structure in Older Adults, Cerebral Cortex, Volume 24, Issue 11, November 2014, Pages 3059–3068, https://doi.org/10.1093/cercor/bht163

8. Yurko-Mauro K, McCarthy D, Rom D, et al; Beneficial effects of docosahexaenoic acid on cognition in age-related cognitive decline. Alzheimers Dement. 2010; 6, 456-64

9. Quinn JF, Raman R, Thomas RG, et al; Docosahexaenoic acid supplementation and cognitive decline in Alzheimer disease: a randomized trial. JAMA, 2010; Nov 3;304(17):1903-11.

10. A David Smith, Fredrik Jernerén, Helga Refsum, ω-3 fatty acids and their interactions, The American Journal of Clinical Nutrition, Volume 113, Issue 4, April 2021, Pages 775–778, https://doi.org/10.1093/ajcn/nqab013

11. Cunnane, Stephen & Schneider, Julie & Tangney, Christine & Tremblay-Mercier, Jennifer & Fortier, Mélanie & Bennett, David & Morris, Martha. (2012). Plasma and Brain Fatty Acid Profiles in Mild Cognitive Impairment and Alzheimer’s Disease. Journal of Alzheimer’s disease : JAD. 29. 691-7. 10.3233/JAD-2012-110629.

12. Richter Y, Herzog Y, Lifshitz Y, Hayun R, Zchut S. The effect of soybean-derived phosphatidylserine on cognitive performance in elderly with subjective memory complaints: a pilot study. Clin Interv Aging. 2013;8:557-63. doi: 10.2147/CIA.S40348. Epub 2013 May 21. PMID: 23723695; PMCID: PMC3665496.

13. Schaefer EJ, Bongard V, Beiser AS, Lamon-Fava S, Robins SJ, Au R, Tucker KL, Kyle DJ, Wilson PW, Wolf PA. Plasma phosphatidylcholine docosahexaenoic acid content and risk of dementia and Alzheimer disease: the Framingham Heart Study. Arch Neurol. 2006 Nov;63(11):1545-50. doi: 10.1001/archneur.63.11.1545. PMID: 17101822.

14. Yuki D, Sugiura Y, Zaima N, Akatsu H, Takei S, Yao I, Maesako M, Kinoshita A, Yamamoto T, Kon R, Sugiyama K, Setou M. DHA-PC and PSD-95 decrease after loss of synaptophysin and before neuronal loss in patients with Alzheimer’s disease. Sci Rep. 2014 Nov 20;4:7130. doi: 10.1038/srep07130. PMID: 25410733; PMCID: PMC5382699.

15. Fairbairn, P., Dyall, S. C., & Tsofliou, F. (2022, Apr 27). The Effects of Multi-Nutrient Formulas containing a Combination of Omega-3 Polyunsaturated Fatty Acids and B vitamins on Cognition in the older adult: A Systematic Review and Meta-analysis. Br J Nutr, 1-42. https://doi.org/10.1017/S0007114522001283

16. Nakazaki E, Mah E, Sanoshy K, Citrolo D, Watanabe F. Citicoline and Memory Function in Healthy Older Adults: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial. J Nutr. 2021 Aug 7;151(8):2153-2160. doi: 10.1093/jn/nxab119. PMID: 33978188; PMCID: PMC8349115.

17. Sommer I, Griebler U, Kien C, Auer S, Klerings I, Hammer R, Holzer P, Gartlehner G. Vitamin D deficiency as a risk factor for dementia: a systematic review and meta-analysis. BMC Geriatr. 2017 Jan 13;17(1):16. doi: 10.1186/s12877-016-0405-0. PMID: 28086755; PMCID: PMC5237198;

18. Jayedi A, Rashidy-Pour A, Shab-Bidar S. Vitamin D status and risk of dementia and Alzheimer’s disease: A meta-analysis of dose-response †. Nutr Neurosci. 2019 Nov;22(11):750-759. doi: 10.1080/1028415X.2018.1436639. Epub 2018 Feb 15. PMID: 29447107;

19. Chai B, Gao F, Wu R, Dong T, Gu C, Lin Q, Zhang Y. Vitamin D deficiency as a risk factor for dementia and Alzheimer’s disease: an updated meta-analysis. BMC Neurol. 2019 Nov 13;19(1):284. doi: 10.1186/s12883-019-1500-6. PMID: 31722673; PMCID: PMC6854782.

20. Jia J, Hu J, Huo X, Miao R, Zhang Y, Ma F. Effects of vitamin D supplementation on cognitive function and blood Aβ-related biomarkers in older adults with Alzheimer’s disease: a randomised, double-blind, placebo-controlled trial. J Neurol Neurosurg Psychiatry. 2019 Dec;90(12):1347-1352. doi: 10.1136/jnnp-2018-320199. Epub 2019 Jul 11. PMID: 31296588.

21. Feart C, Helmer C, Merle B, Herrmann FR, Annweiler C, Dartigues JF, Delcourt C, Samieri C. Associations of lower vitamin D concentrations with cognitive decline and long-term risk of dementia and Alzheimer’s disease in older adults. Alzheimers Dement. 2017 Nov;13(11):1207-1216. doi: 10.1016/j.jalz.2017.03.003. Epub 2017 May 16. PMID: 28522216.

By Robert H. Lustig, MD, MSL

Most people know that refined sugar is not good for you, but what is it about sugar that’s particularly bad for your brain? Why is it essential, not only for brain health and dementia prevention, to reduce your intake of not only sugar but refined carbohydrates in general? (By refined, I mean those whose fiber has been processed away – not ‘whole’ as in vegetables, whole fruit (not juice), beans, and whole grains.

Let’s start at the extreme. What happens if you lived at the North Pole, and ate virtually no carbohydrates, or at least so little as to force your body and brain to switch to a kind of fuel, ketones, produced from fat? This is often called a “very low carb high fat” (LCHF) or “ketogenic” diet. Would you get sick? This is what Vilhjamur Steffanson did, when his Arctic exploration shipwrecked in 1913, and he was forced to live amongst the Inuit for two years. He noted that there was no diabetes, no cancer — and no Alzheimer’s. In 1928, he and his colleague checked themselves into Bellvue hospital, and ate only meat for one year.[1]They were healthier than the researchers who studied them! 

Your brain likes ketones

Ketones are made in the liver from fat – either breaking down your own fat (for example, if you were fasting, eating very little or exercising a lot), or from ingestion of a type of fat containing ‘medium chain triglycerides’ (MCTs). Coconut oil is approximately 54% MCTs and contains all 4 MCTs (C6, C8, C10, C12), but it turns out that one particular kind of MCT, called C8 because it is 8 carbons long, is the best fat for the liver to convert into ketones.

You may be surprised to know that your brain can run well on glucose (the kind of sugar that is fuel for our cells), but even better on ketones. The reason is that ketones cross into the brain easily, rapidly, and without a biochemical transporter. This is why children with severe epilepsy improve on a ketogenic diet. Watch this short film ‘Fuel your Brain’.

Brain benefits of a low-carb ketogenic diet

In fact, brain cells prefer ketones. In two studies, one on people with Alzheimer’s and the other on those with pre-dementia or mild cognitive impairment, giving 2 tablespoons of C8 oil (called capricin or caprylic acid triglyceride), brain energy derived from ketones went up by 230% and memory and mental acuity improved in those with Minimal Cognitive Impairment (MCI).[2,3]

A ketogenic diet has been shown to reduce schizophrenia symptoms, help reduce shaking in Parkinson’s, and slow down cognitive decline in those with dementia or pre-dementia. In fact, the ketogenic diet has been used to effectively treat childhood epilepsy for over 100 years! There’s a good review on the current status of the ketogenic diet in psychiatry here^.[4]

Ketogenic diets may help in many ways. Firstly, when a person eats too much carbohydrate, sugar, but especially fructose, damages the energy burning factories in cells, called mitochondria, so their ability to produce chemical energy for the neuron is greatly reduced. Switching to burning ketones instead can increase mitochondria number and function. A recent study also shows that a ketogenic diet has a positive effect on the gut microbiome,[5] and this might be one way the diet helps reduce fits in people with epilepsy.[6] Fructose, on the other hand, disrupts the gut microbiome in a negative way.

How sugar damages your brain

But what is it about a ketogenic diet that is good for your brain? Is it the ketones, the lowering of insulin, the type of fat, the elimination of carbohydrate, or specifically the elimination of sugar? We don’t yet know – I ask this question of every Alzheimer’s and metabolic researcher I know, and no one can tell me – just that it works.

There are a few possible mechanisms. First, the more carbs and sugar you eat, the more resistant you become to the hormone insulin. Insulin not only drives glucose into cells (including brain cells), but also sends excess sugar to the liver to turn into fat. When a person becomes insulin resistant, ironically, glucose transport is negatively impacted, reducing brain energy availability. Insulin resistance is a major driver of depression.[7] A ketogenic diet can reverse that. 

Fructose, which comprises half of sucrose (‘white’ or ‘table’ sugar), and half of ‘high-fructose corn syrup’ (added to numerous processed foods), damages our mitochondria, which leads to less brain energy availability. One study showed that fructose reduces liver mitochondrial function, while glucose stimulates it^.[8]  “The most important takeaway of this study is that high fructose in the diet is bad,” said Dr. C. Ronald Kahn from the Joslin Diabetes Center.  “It’s not bad because it’s more calories, but because it has effects on liver metabolism to make it worse at burning fat. As a result, adding fructose to the diet makes the liver store more fat, and this is bad for the liver and bad for whole body metabolism.”

Fructose is the main sugar in most fruits. People then extrapolate, “oh fruit must be bad for you.” Not true. Whole fruit has fibre (both soluble and insoluble); together they slow down glucose and fructose absorption in the GI tract limiting both liver and brain exposure, and they also help feed the gut bacteria (microbiome), so actually you get less fructose entering the bloodstream. Juicing the fruit removes the protective fiber, and juice has been shown to be just as dangerous to metabolism as is soda. So, eat your fruit — don’t drink it!

Carbohydrates and fructose age your brain

There’s another reason why sugar, and especially fructose, is bad for your brain and body. They produce Advanced Glycation Endpoints or AGEs, which damage the brain. These ‘oxidise’ proteins (so does cigarette smoke), rendering them useless , allowing them to aggregate into clumps, and use up valuable antioxidants in your diet such as vitamin C and E.

Fructose acts on your liver to switch your metabolism away from fat burning to fat making and storing, and inhibits an anti-ageing process called ‘autophagy’ which helps clean up and remove damaged mitochondria in order to regenerate new, healthier cells.

Why sweet foods are so addictive

So far we’ve only explored why sugar is bad for your “physical” brain. Knowing this is a good start. But why does your “emotional” brain keep telling you that you want it? Why do people find it so hard to resist, and so many become sugar addicts? The answer is that fructose activates the “reward system” in the brain. It causes dopamine release, the motivational neurotransmitter associated with ‘reward’. Any chemical that does so can be addictive – cocaine, heroin, alcohol, nicotine, or example. The trouble is the more you have, the more your brain ‘down-regulates’, i.e. becomes less responsive to your own natural feel-good dopamine, so you end up needing more sugar to get the hit and, in the end, you get no hit at all but feel thoroughly awful without it. That’s the Law of Diminishing Returns. That’s addiction.

Blood sugar control reduces dementia risk

Keeping blood glucose levels in the low-normal range is reflected by a low blood glycosylated haemoglobin (HbA1C) level, which means ‘sugar-coated red blood cells’. A low HbA1c is good and is a proxy for improved insulin sensitivity, associated with reduced risk for dementia in several studies.[9,10,11,12,13,14] 

A new study also shows that, in 40 year old adults with so-called normal glucose levels but at the higher end of the normal range, have increased their risk of Alzheimer’s by 15% [37]

Type 2 diabetes, the net result of losing blood sugar control, almost doubles the risk for dementia.[15,16] Diabetes is also associated with more rapid brain shrinkage.[17,18] Even people in the upper normal range of blood glucose have increased brain atrophy, impaired cognition, and increased risk of dementia.[19,20]

For instance, one trial measured HbA1c and glucose levels in several thousand elderly people over the course of almost seven years. In that time, slightly more than a quarter of the participants developed dementia, and the bottom line was that rising glucose levels were associated with increased risk of developing the condition, irrespective of whether the participants also had diabetes. Non-diabetics who experienced a modest increase in blood sugar levels had an 18% increased risk of dementia, as compared to those who already had diabetes at the start of the study or developed it within the trial period, who had a 40% increased risk.[21]

Prevention action – how to cut down your sugar load

In practical terms, preventing dementia today means avoiding sugar as much as possible.  If you’re going to eat carbohydrate, eat ‘whole’ carbohydrate foods such as whole vegetables, fruits (not juice), beans, only wholegrain bread (labelled as ‘100% wholegrain’, or pasta in small quantities. 

Starchy carbohydrates such as pasta, rice and potatoes benefit from being cooked and cooled, then eaten cold or re-heated, as some of the carbohydrate is converted into resistant starch – a type of fibre we can’t digest but which has the added benefit of fermenting and feeding our gut bacteria.

Make sure the carbohydrate comes with its inherent fibre. Oat cakes would be better than bread since the fibre in these foods helps ‘slow release’ the sugars. Eating white bread is associated with a poorer cognitive test performance, whereas high fibre bread is associated with better performance.[34] Eating carbohydrate foods with protein, for example brown rice with fish, or porridge oats with seeds, or fruit with nuts, further reduces the glycemic load (GL) of a meal. The best fruits in this respect are low-sugar high-fiber fruits like berries, cherries, and plums.

These kinds of foods are consistent with a Mediterranean diet which has also been shown to reduce risk.[35] Conversely, grapes, raisins, and bananas are high GL. A study in Finland and Sweden compared those with a healthy versus unhealthy diet, including the above criteria, in mid-life for future risk of developing Alzheimer’s disease and dementia 14 years later. Those who ate the healthiest diet had an 88% decreased risk of developing dementia and a 92% decreased risk of developing Alzheimer’s disease.[36] 

The take-home message is, if you are going to eat complex carbohydrates, eat them with fibre, fat and protein.

However, if you want to go one step further, you can switch to eating a ketogenic low-carb, high fat diet. The problem with the ketogenic diet is staying on it – there’s so much carbohydrate out there it’s hard to avoid it. But there are now breath monitors (e.g. Ketoscan, BioSense from ReadOut Health) that can help you stay in ketosis. A good book to help you explore and put into practice either a low carb ketogenic diet or a low GL diet is ‘The Hybrid Diet’ by Patrick Holford & Jerome Burne. And to understand how processed food is your enemy, take a look at my book ‘Metabolical’.

And if you want to know how sugar is impacting your body and brain then you can take one of our at-home, pin-prick, DRIfT blood test so you can know exactly how sugar is impacting your body and also become a part of our vital research into this area.

Become a Citizen Scientist & Join our Research today!

Food for the Brain is a non-for-profit educational and research charity that offers a free Cognitive Function Test and assesses your Dementia Risk Index to be able to advise you on how to dementia-proof your diet and lifestyle.

By completing the Cognitive Function Test you are joining our grassroots research initiative to find out what really works for preventing cognitive decline. We share our ongoing research results with you to help you make brain-friendly choices

Please support our research by becoming a Friend of Food for the Brain.

References:

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23. Abbatecola AM, Paolisso G, Lamponi M, Bandinelli S, Lauretani F, Launer L, Ferrucci L. Insulin resistance and executive dysfunction in older persons. J Am Geriatr Soc. 2004 Oct;52(10):1713-8. doi: 10.1111/j.1532-5415.2004.52466.x. PMID: 15450050.

24. Ye X, Gao X, Scott T, Tucker KL. Habitual sugar intake and cognitive function among middle-aged and older Puerto Ricans without diabetes. Br J Nutr. 2011 Nov;106(9):1423-32. doi: 10.1017/S0007114511001760. Epub 2011 Jun 1. PMID: 21736803; PMCID: PMC4876724.

25. Seetharaman S, Andel R, McEvoy C, Dahl Aslan AK, Finkel D, Pedersen NL. Blood glucose, diet-based glycemic load and cognitive aging among dementia-free older adults. J Gerontol A Biol Sci Med Sci. 2015 Apr;70(4):471-9. doi: 10.1093/gerona/glu135. Epub 2014 Aug 22. PMID: 25149688; PMCID: PMC4447796.

26. Power SE, O’Connor EM, Ross RP, Stanton C, O’Toole PW, Fitzgerald GF, Jeffery IB. Dietary glycaemic load associated with cognitive performance in elderly subjects. Eur J Nutr. 2015 Jun;54(4):557-68. doi: 10.1007/s00394-014-0737-5. Epub 2014 Jul 18. PMID: 25034880.

27. Taylor MK, Sullivan DK, Swerdlow RH, Vidoni ED, Morris JK, Mahnken JD, Burns JM. A high-glycemic diet is associated with cerebral amyloid burden in cognitively normal older adults. Am J Clin Nutr. 2017 Dec;106(6):1463-1470. doi: 10.3945/ajcn.117.162263. Epub 2017 Oct 25. PMID: 29070566; PMCID: PMC5698843.

28. Taylor MK, Sullivan DK, Swerdlow RH, Vidoni ED, Morris JK, Mahnken JD, Burns JM. A high-glycemic diet is associated with cerebral amyloid burden in cognitively normal older adults. Am J Clin Nutr. 2017 Dec;106(6):1463-1470. doi: 10.3945/ajcn.117.162263. Epub 2017 Oct 25. PMID: 29070566; PMCID: PMC5698843.

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The mouth is a hub of activity, housing around 50–100 billion bacteria from 200 different bacterial species. The role of these resident bacteria in the mouth, also known as the oral microbiome, is an emerging area of research. Alterations in the oral microbiome may occur as a result of factors including consuming high amounts of sugar, smoking tobacco and experiencing chronic stress. Drinking large amounts of alcohol can also negatively impact the oral microbiome. Disruptions to the oral microbiome can lead to gut dysbiosis, which has been associated with increased permeability of the Blood Brain Barrier (BBB). 

Findings to date suggest that the oral microbiome, via interactions with the gut and brain (a network called the oral-gut-brain axis), may be a key consideration for brain health, and multiple associated conditions. This post will focus on three key areas where there is present research: autism, Down’s syndrome, and Alzheimer’s disease. 

Autism

Individuals with autism have been indicated to have alterations in their oral microbiome, as well as gut dysbiosis and related disruptions to the gut-brain axis. A study investigating the oral microbiome indicated that children with autism have a higher incidence of gastrointestinal disturbance and food allergies. Moreover, children with autism were observed to have a disruption to the ratio of Firmicutes: Bacteroidetes bacteria, in favour of Firmicutes. Balance of the Firmicutes: Bacteroidetes ratio is key for integrity of the gut, and disruptions to this ratio are indicative of gut dysbiosis.  

Moreover, two specific groups of bacteria, Brucella and Enterococcus faecalis were observed to be elevated in autistic children, whilst Flavobacterium sp. levels were demonstrated to be decreased. Research has suggested that individuals with autism have a higher risk of developing Alzheimer’s disease earlier in life. One potential mechanism for this could be due to alterations to the Firmicutes: Bacterodetes ratio.

Firmicutes and Bacteroidetes both utilise amyloids in the gut as structural material. Recognition of amyloids may become impaired by increased synthesis of inflammatory T cells by the innate immune system, as the result of intestinal permeability. Translocation of amyloids across the BBB has been hypothesised to be associated with enhanced Aβ deposit in the brain, although this requires further research.

Down’s Syndrome

Individuals with Down’s syndrome have been demonstrated to be more susceptible to periodontitis, or gum disease. One potential explanation for these findings could be due to alterations in oral microbiome composition. One study observed that individuals with Down’s syndrome have higher levels of Streptococcus mutans in their saliva. A further study observed increased levels of the pathogenic bacterial strains Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis.  Individuals with Down’s syndrome have an increased risk of developing Alzheimer’s disease later in life, with 50% of individuals >60 years of age meeting diagnostic criteria for dementia. One hypothesised mechanism for this is because of altered expression of inflammation and immune system modulating genes in periodontitis.

Alzheimer’s Disease

Individuals with Alzheimer’s disease have been observed to have higher levels of the oral bacteria, Treponema, in the brain. Moreover, disruptions to the oral-gut-brain axis has been associated with increased accumulation of beta amyloid and Tau, two key markers of Alzheimer’s disease.

Supporting the Oral-Gut-Brain Axis 

Supporting the oral-gut-brain axis is an area of research that is undeveloped, however, it seems logical that many of the measures employed for supporting gut and brain health would also be salient. 

Increase Fibre & Polyphenols

Consuming a wide array of colourful vegetables, fruits, herbs and spices is a great way of increasing prebiotic fibres, which help to support gut health via increasing production of SCFAs (short chain fatty acids), and polyphenols, plant compounds that have antioxidant properties and have been demonstrated to support the oral-gut-brain axis. 

Increase Omega-3 Fats

Omega-3 fats exert anti-inflammatory effects in the body, whilst increasing microbiome diversity via balancing the Firmicutes: Bacteroidetes ratio, which is essential for gut health and gut barrier integrity. Additionally, increased levels of omega-3 have been associated with reduced incidence of periodontitis. Ways to increase omega-3 include increasing consumption of oily fish such as salmon, mackerel and sardines, and also flaxseeds, walnuts and algae. 

Increase Fermented, Probiotic Foods

Probiotics have been associated with improved oral health due to decreased presence of pathogenic bacteria in the mouth. Examples of probiotic foods include fermented foods such as kimchi, kombucha, kefir, sauerkraut and sourdough bread.

Exercise plays an important role in cognition. In this TED talk listen to expert Dr Wendy Suzuki explaining in more detail.

Dr Wendy Suzuki – The Brain Changing Benefits of Exercise (TED).

Mental health conditions are on the rise and the statistics speak for themselves: a record 70 million antidepressant prescriptions were handed out in 2018, and an estimated 10 million people will be in need of mental health support in the next five years. Mood can of course be dependent on external factors, but internal factors such as fluctuations in hormones, neurotransmitters and nutrient availability can also exert considerable influence. In light of this, treating the mind and body separately does not make sense. 

Our Second Brain

Far from being distant organs, the gut and brain communicate through a complex network of neural, hormonal and immune pathways and messengers, called the “gut-brain axis”. The integrity of our digestive system directly impacts the information our brain receives, and the quality of the building blocks of the brain tissue itself.  

Poor mental health may be a symptom of imbalances in the gut-brain axis. More  than 100 million nerve cells line our gastrointestinal tract, working independently of our brains. We know that the gut-brain axis is a strong communication mechanism because anxiety and mood changes are correlated with irritable bowel syndrome and functional bowel problems such as constipation, diarrhea, bloating, pain and stomach upset.

Our mood can also be impacted by poor vagal tone. The vagus nerve connects our digestive system to our brain and is the major nerve in our ‘rest and digest’ nervous system. With busy and stressful lifestyles regularly triggering our ‘fight or flight’ response, this vagus nerve may not be functioning well, which can contribute to depression and indigestion. 

Mood and Immunity

The nervous and immune systems work together, with the brain housing specialised immune cells called microglia to help fight infections and clear away damaged cells. When stress is excessive, or when the immune system sends persistent distress signals, the inflammatory response triggered by the immune system has been linked with depression.  

Much of the immune system is housed in our gut, making sense when much of our environmental risk exposure enters the body through our food. Our gut, therefore, needs to be in good shape for our immune system to be working well.  

Maintaining Balance

Our blood sugar levels also impact our mood. Our brain is an energy hungry organ, using 25% of our total energy stores and preferring glucose to carbohydrates to keep it going. If our blood glucose levels are unstable, say from a high carbohydrate diet, this can be stressful for the brain to cope with and can cause mood swings or feeling ‘hangry’.   

Blood sugar swings can also make us feel fatigued and have a detrimental impact on an important protein, BDNF (brain-derived neurotrophic factor) essential for the survival and growth of brain cells. BDNF helps our brain cells communicate and promotes the calming neurotransmitter GABA, levels of which may be low in anxiety sufferers. It also supports how our body makes energy,  and therefore if levels of BDNF are low, we are more likely to feel fatigued, listless and at risk of experiencing mental ill health. 

Top Tip

Keeping our gut healthy with a Mediterranean style diet, abundant in fibre-rich fruit and vegetables, oily Omega-3 rich fish, and wholegrains enriched with B-vitamins, translates into increased brain health, in turn improving our mood and mental health. 

With thanks to Julie Pichler at Vagus Wellbeing for this article. Julie is a registered Nutritional Therapist and delivers our Workplace Wellbeing programme, offering educational and empowering webinars. Julie’s specialism is the gut-brain connection and how food impacts our mood and brain health.

Find out more about our webinars here and how they can support your employees’ mental wellbeing.