Two nutrients proven to stop your brain shrinking
By Jerome Burne & Patrick Holford
New research shows that the combination of B vitamins and omega-3 are a dynamic duo against dementia, stopping the brain shrinkage that is the hallmark of Alzheimer’s.
The discovery, hailed as the “a major step towards Alzheimer’s prevention” was first made at the University of Oxford, but has now been confirmed by research groups in Holland, Sweden and China.
Headed by Professor David Smith, former Chair of Pharmacology and Deputy Head of the Division of Medical Sciences at Oxford University and director of the Oxford Project to Investigate Memory and Ageing (OPTIMA), the research has found that giving older people with the first signs of cognitive impairment supplemental B vitamins (B6, B12 and folic acid) at higher levels than can be achieved through diet to those with sufficient omega-3 fats produced 73% less brain shrinkage in a year, compared to placebo. This reduction brought brain shrinkage down to the level found in those elderly with no cognitive decline. The trial was part-funded by Alzheimer’s Research UK (ARUK). “The effect is greater than that of any drug treatment to date – with no adverse effects.” says Professor Smith. In contrast the recent trials of anti-amyloid drugs have reduced brain shrinkage by 2%.

“Brain shrinkage is the hallmark of Alzheimer’s so this was a vital discovery for its prevention” says Patrick Holford, director of the Alzheimer’s Prevention Project at foodforthebrain.org, the UK’s leading dementia prevention charity “However we needed confirmation from other research groups. Now we have it.”.
Three other research groups have confirmed the combined effect of omega-3 and B vitamins is greater than either nutrient on its own.
“You literally cannot build brain cells without both omega-3 fats and sufficient B vitamins” says Holford. “If you give a builder a hammer or a bag of nails you don’t get a house. But if you give them both they can build a house. The B vitamins drive a process called methylation which assembles the critical brain-building fats that make up the membrane of neurons, through which all brain communication happens. Both are vital for building brain cells. Neither can work without the other.”
Watch this one minute film, on how to build new brain cells at any age.
Realising that the combination of B vitamins and omega-3 fats is key, researchers in Holland, who had previously run a major trial called B-proof that had tested the effects of B vitamins on memory but had only found very modest benefits decided to take reanalyse the results of their B vitamin trial according to the participants blood levels of omega-3 at the start of the trial. Sure enough, they found no benefit at all from the B vitamins in those with low omega-3 status, but a massive improvement in cognition in those in the top third of omega-3 levels.[i]
Could this need for both explain why some trials testing omega-3 were also not successful?
The Oxford University researchers, led by Dr Frederik Jerneren, were given access to the blood samples from another trial in Sweden called OmegAD. This trial had given older people a hefty dose of 2.3grams (two large capsules) of omega-3 fish oils. The trial had apparently failed, showing no significant cognitive benefit. Could faulty methylation, a result of lack of B vitamins, be the reason for the omega-3 fish oils not working?
The Oxford researchers therefore measured homocysteine, a consequence of a lack of B vitamins, in the samples from the OmegAD trial. Dr Jerneren split the participants into thirds – from the lowest to highest level of homocysteine. Those given omega-3 who had the lowest homocysteine, in other words sufficient in B vitamins, had a highly significant improvement in their clinical dementia rating while those with high homocysteine (poor B vitamin status) had no benefit at all.[ii] The group with sufficient vitamin B showed a reduction in their clinical dementia score that was more than three times that reported from the recent Lecanemab drug trial.[iii]
Meanwhile another trial, this time in China, gave those with pre-dementia either the B vitamin folic acid, or omega-3, or both, compared to placebo. Although B vitamin treatment and omega-3 treatment did slightly improve cognitive cores, the improvement was much greater in those given both thee nutrients.[iv]
With 170 million people over 65, Chinese authorities are taking prevention of dementia extremely seriously to avoid a cerebral tsunami. So, one of their top researchers, Professor Jin-Tai Yu at Shanghai’s Institute of Neurology at Fudan University did one of the most thorough reviews of all risk factors for Alzheimer’s to date.[v]
“Lowering blood homocysteine levels, an established indicator of Alzheimer’s risk, with B vitamins is a most promising treatment.” he concluded. He was also given access to the UK’s Bio Bank data of almost half a million people “Our current research, using data from the UK Bio Bank, shows that having higher blood levels of polyunsaturated fats, including omega-3, and supplementing fish oils, is associated with less risk of dementia. [vi] Moreover, recent studies suggest these two factors – homocysteine lowering B vitamins, and omega-3 – may, in combination, be potentially more beneficial. They are easy to implement. This is worthy of further research”
The UK’s Bio Bank data showed that something as simple as taking fish oils had reduced dementia risk by 9%. This is equivalent to the risk reduction found from quitting smoking.[vii]
US researchers at the National Institutes of Health research have confirmed this, attributing almost a quarter (22%) of Alzheimer’s cases to lack of B vitamins and raised homocysteine levels and the same (22%) to a lack of omega-3 and seafood intake.[viii] This means that about one in three cases of Alzheimer’s could be avoided simply by taking a daily high dose B vitamin supplement and an omega-3 fish oil capsule. This could save 95,000 people a year in the UK from developing dementia. Currently, 790 people – seven double decker buses worth – are diagnosed every single day. However, the benefit is not just in preventing people from dementia in the future. A study of healthy 65-year-olds given omega-3 fish oils showed both improvement in memory and healthier brain tissue within six months.[ix]
The Alzheimer’s prevention charity, foodforthebrain.org, targets eight prevention steps in their on-line Cognitive Function test and Dementia Risk Index questionnaire, including B vitamins and omega-3. “These are the two easiest to change and most evidence based prevention steps anyone can take.” Say Patrick Holford who directs their ‘Alzheimer’s is Preventable’campaign.
[i] van Soest, A.P.M., van de Rest, O., Witkamp, R.F. et al. DHA status influences effects of B-vitamin supplementation on cognitive ageing: a post-hoc analysis of the B-proof trial. Eur J Nutr (2022). https://doi.org/10.1007/s00394-022-02924-w
[ii] Jernerén F, Cederholm T, Refsum H, Smith AD, Turner C, Palmblad J, Eriksdotter M, Hjorth E, Faxen-Irving G, Wahlund LO, Schultzberg M, Basun H, Freund-Levi Y. Homocysteine Status Modifies the Treatment Effect of Omega-3 Fatty Acids on Cognition in a Randomized Clinical Trial in Mild to Moderate Alzheimer’s Disease: The OmegAD Study. J Alzheimers Dis. 2019;69(1):189-197. doi: 10.3233/JAD-181148. PMID: 30958356.
[iii] Walsh S, Merrick R, Richard E, Nurock S, Brayne C. Lecanemab for Alzheimer’s disease. BMJ. 2022 Dec 19;379:o3010. doi: 10.1136/bmj.o3010. PMID: 36535691.
[iv] Li M, Li W, Gao Y, Chen Y, Bai D, Weng J, Du Y, Ma F, Wang X, Liu H, Huang G. Effect of folic acid combined with docosahexaenoic acid intervention on mild cognitive impairment in elderly: a randomized double-blind, placebo-controlled trial. Eur J Nutr. 2021 Jun;60(4):1795-1808. doi: 10.1007/s00394-020-02373-3. Epub 2020 Aug 28. PMID: 32856190.
[v] 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.
[vi] Huang Y, Deng Y, Zhang P, Lin J, Guo D, Yang L, Liu D, Xu B, Huang C, Zhang H. Associations of fish oil supplementation with incident dementia: Evidence from the UK Biobank cohort study. Front Neurosci. 2022 Sep 7;16:910977. doi: 10.3389/fnins.2022.910977. PMID: 36161159; PMCID: PMC9489907.
[vii] Jeong SM, Park J, Han K, Yoo J, Yoo JE, Lee CM, Jung W, Lee J, Kim SY, Shin DW. Association of Changes in Smoking Intensity With Risk of Dementia in Korea. JAMA Netw Open. 2023 Jan 3;6(1):e2251506. doi: 10.1001/jamanetworkopen.2022.51506. PMID: 36656579; PMCID: PMC9857334.
[viii] 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.
[ix] Witte AV, Kerti L, Hermannstädter HM, Fiebach JB, Schreiber SJ, Schuchardt JP, Hahn A, Flöel A. Long-chain omega-3 fatty acids improve brain function and structure in older adults. Cereb Cortex. 2014 Nov;24(11):3059-68. doi: 10.1093/cercor/bht163. Epub 2013 Jun 24. PMID: 23796946.