Turkey, salmon and Brazil nuts are familiar Christmas fayre that also happen to be excellent sources of proteins, B vitamins and the essential element selenium. All these nutrients have been linked to maintaining brain health, but the selenium content of our food is attracting new scientific interest because it is an essential factor in our diet that helps to remove hydrogen peroxide from in and around cells. Hydrogen peroxide is produced during normal cell function, but it has the potential to damage brain cells if it builds up.

Only a very small amount of selenium is required for good health and sufficiency is easily achieved from a healthy balanced diet that has been derived from well managed soils. However, a recent study revealed that approximately 50% of women and 25% of men living in the UK may not be reaching the lower recommended dietary intake for selenium.

Surprisingly, just one Brazil nut a day (about 5g) will give your selenium intake a good boost!

A Brazil nut provides roughly 12.7 micrograms (mcg) of selenium (according to the UK Food Standards Agency dataset). Therefore, two a day should make good progress towards reaching the UK government recommended intake (75mcg per day for adult males and 60mcg per day for adult females). Brazil nuts vary enormously in selenium content; do check the nutritional information on the packet. For comparison, a 100g serving of salmon provides approximately 21mcg selenium and a 100g serving of turkey provides approximately 14mcg selenium.

What is the relevance of selenium rich foods to brain health? 

Studies suggest that there is an intriguing connection between Alzheimer’s disease and selenium insufficiency. A small preliminary trial has revealed surprising results; consuming one Brazil nut daily for 6 months was sufficient to have a positive effect on some cognitive function in older adults with mild cognitive impairment. More research is underway.

A word of warning though: be aware that eating too many Brazil nuts and taking a supplement will move you towards the limit of safe intake for selenium. The currently accepted safe level for selenium is below 450mcg a day for a 60kg adult. Ask your healthcare provider to check your selenium status before taking a supplement.

It wouldn’t be Christmas without sprouts!

Brussels sprouts and the other cruciferous vegetables such as broccoli and cauliflower are a fantastic source of many nutrients including vitamin K, folate and carotenoids. The signature ‘bitter’ flavour of cruciferous vegetables is provided by sulphur-containing compounds that are essential for the body to maintain lots of important functions.

Interestingly, sulphur and selenium work alongside each other in every cell throughout the body to remove hydrogen peroxide, a molecule that acts as a trigger for inflammation and may be a contributing factor to neurodegeneration.

Does regular consumption of cruciferous vegetables reduce inflammation and slow-down neurodegeneration in humans? We don’t have the answer yet, but there has been a call for studies to investigate this potentially important link between diet and disease.

Christmas herbs and spices

Spices may seem expensive, but they store well and are useful for adding interesting flavours to food, helping us to use less salt. They provide a host of other health benefits too.

Ginger, allspice, cloves, cinnamon and thyme are synonymous with the warming flavours of Christmas drinks, savoury foods, desserts, sauces and chutneys. Traditional herbal medicine has long valued these spices and herbs as effective aids to digestion, and more recent studies indicate that they have antioxidant, anti-fungal and antibacterial effects too.

It is easy to overlook the significance of herbs and spices in enabling effective digestion because we only use them in very small amounts, but they are a first line of defence that is very useful to reduce some of the challenges faced by our own cells. They may also enhance breakdown and control absorption of the nutrients present in our food.

Effective digestion is necessary to feed our body and brain to keep us healthy and functioning well throughout the year.

Studies suggest that the health benefits from these herbs and spices are not limited to the digestive tract; the complex array of chemicals they contain may work in harmony or in a synergistic way within and around human cells. For example, cinnamon may help to improve blood sugar control and improve lipid profiles for people with type II diabetes and, along with allspice, cloves and thyme, may also be efficient at reducing the formation of glycated proteins. Glycated proteins are a complication of type II diabetes and implicated in ageing and neurodegenerative conditions such as Huntington’s disease and Parkinson’s disease.

Key points

Brazil nuts, turkey and salmon are excellent sources of protein and selenium (Brazil nuts are a rich source of selenium so limit intake to a few a day)

Dietary selenium is essential, and helps to protect against brain cell damage

Human studies suggest that Alzheimer’s disease patients may have a lower selenium status

Ask your doctor to check your selenium status before taking a supplement

Cruciferous vegetables such as Brussels sprouts and broccoli provide important sulphur-compounds that work with selenium to reduce the damage caused by normal inflammatory responses in the body and brain

Try new recipes that help you to incorporate seasonal cruciferous vegetables, herbs and spices in your regular diet throughout the year

Including herbs and spices into our regular diet may indirectly support long-term brain health, but there is currently a lack of evidence for this from human studies

Small amounts of ginger, allspice, cloves, cinnamon and thyme help us to keep healthy by aiding digestion, supplying antioxidants and helping our immune cells to resist bugs

Studies suggest that cinnamon may be helpful to balance blood sugar levels

Alternative uses for Christmas herbs and spices

Infuse a cinnamon stick when you make apple sauce. Serve the spiced apple with yoghurt for a quick dessert or use in a crumble

Add a sprinkle of ground cinnamon when preparing overnight oats for breakfast the next day

Use spices to pump up the flavour of homemade curry sauces, marinades and stir-fries; ginger, allspice, cloves and cinnamon all work well in sweet and savoury recipes.

Make a simple garlic and thyme infused olive oil to use in your cooking: Save an empty jam or pickle jar, wash and dry it thoroughly. Add 1-2 tablespoons dried thyme and the skinned cloves from half a large garlic bulb to the jar, then pour in 250ml extra virgin olive oil. Put on the lid, give it a good shake every day for a week. Leave to infuse at room temperature for a week and then discard the garlic cloves and store the oil in the fridge door. Infused oils go wonderfully with quick cook turkey steaks, fish, drizzled over poached eggs or oven roasted vegetables and a great start when frying onions for a savoury dish

A thyme tea made with a pinch of dried thyme in 250ml of boiling water and left to infuse for 10 minutes then strained before drinking is reviving, helpful for digestion and may also be beneficial if you have a cough or chest infection. Add a squeeze of lemon and a dash of honey for extra flavour

Treat your brain this Christmas… enjoy a dark chocolate coated Brazil nut everyday through the festive season!

With thanks to Tracey Hipkiss, Food for the Brain Volunteer, for this article.