5 ways the food you eat affects your brain
Does food influence how you think and feel? We asked a dietitian to explain how different foods, drinks and nutrients affect the brain
Ever wondered how the food you eat affects your grey matter? Sadly, there are no miracle 'brain foods' that’ll make you the next mastermind or completely protect against age-related disorders, such as Alzheimer's or dementia, or protect you from the numerous medical conditions that affect the brain; however, what you eat (or don't eat) may make a difference. We asked dietitian Emer Delaney for her insights.
What is the brain?
The most complex part of the human body, the adult brain weighs about 3lbs and is involved in learning and memory, emotion, touch and movement. It controls our breathing, temperature, hunger and our behaviour.
Following a healthy diet and lifestyle provides the nutrients and conditions the brain needs to work to the best of its ability.
What is a brain-friendly diet?
Eating a wide variety of fruit and vegetables that contain lots of vitamins, minerals and antioxidants will help nourish the brain and protect it from oxidative stress, which can potentially damage cells.
Research suggests a healthy eating pattern – in particular, the Mediterranean diet – may provide this protection. This means eating a diet rich in fruit, vegetables, wholegrains, nuts, seeds and healthy oils and fats. Research suggests this sort of diet may help slow the rate of cognitive decline, lower the risk of cognitive impairment and potentially lower the risk of dementia.
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How does the food you eat affect your brain?
1. Energising carbs
The brain only accounts for about two per cent of our body weight, but it consumes almost 20 per cent of glucose-derived energy – meaning nutrition is key for brain fuel.
The greatest source of energy for our brain comes from carbohydrates like wholegrains, vegetables, fruit, rice, potatoes and lactose (the sugar found in milk). These are considered healthy carb sources and are broken down by the body into glucose and used by our brain as energy. Without an adequate intake, the brain cannot function correctly – so you may experience brain ‘fog’, lack of focus and irritability.
Glucose forms the building blocks of these carb foods and, as well as fuelling the brain, plays a role in the production of the feel-good chemical, serotonin. Serotonin is responsible for balancing our mood and relieving anxiety.
Some scientists believe refined table sugar – the white stuff you add to tea and coffee and found in biscuits and cakes, may produce addiction-like effects in the brain, however there are mixed views on this with no conclusive evidence to date.
2. Foundational fats
Specific fats are crucial to the brain as they are a key component in the structure of cell membranes and play a role in the structure and function of nerve cells, called neurons. We know that approximately 60 per cent of the brain is made up of omega-3 fats with DHA, being the main type.
Omega-3 fats found in fatty fish like salmon, herring and sardines as well as nuts, like walnuts, and seeds like flaxseed are essential for brain development in the womb and early childhood. The majority of brain cells are developed before birth, with the remaining being laid down in the first year of life. This means it’s important to include sources of omega-3 fats during pregnancy and early childhood.
There is also evidence to suggest that a lack of these fats in the diet may have an adverse effect on cognition and that if you eat a plentiful amount they may be associated with a reduction in the development and progression of dementia. Despite these encouraging results, cause and effect has yet to be demonstrated – so again, larger studies are needed before we can determine the exact relationship between fat intake and cognitive health.
To boost the beneficial fats in your diet, try our recipes for sesame salmon, purple sprouting broccoli & sweet potato mash, grilled aubergines with spicy chickpeas & walnut sauce, and apricot & seed overnight chia.
3. Vital vitamins and minerals
B vitamins as well as vitamins C, D and E and the mineral magnesium are all essential for brain health and development. Research shows that a diet rich in these micronutrients is associated with a lower risk of developing cognitive problems during aging.
Vitamin B1 and vitamin E are important for cells that transmit messages from the nerves, whilst B6, B12 and vitamin C play an important role in how the nerves work and are formed. Magnesium, found in avocado, spinach, brown rice and nuts, improves neural plasticity, meaning the nerves are able to adapt and avoid damage. As a result, eating adequate magnesium may improve memory, help to fight stress and depression and be crucial for the production of energy and neurotransmitters.
Epidemiological studies suggest that adequate intake of vitamins and minerals is associated with a lower risk of developing cognitive deficits. The B vitamins and vitamins E, C, and D have all been identified as playing important roles in maintaining normal brain function. Members of the B group of vitamins and vitamin C are also essential for energy production in the brain.
4. Beneficial gut bacteria (probiotics)
It is widely accepted that there is a two-way communication between the gut and the central nervous system which works via biochemical signalling. We often refer to this as the 'gut-brain axis', as this describes the link between the cognitive and emotional areas of our brain and our gut.
There’s been a lot of interest in the role beneficial gut bacteria, known as probiotics, play in the health of our gut and the function of our brains. It is believed that probiotics change the processing of information in the gut that is strongly linked to anxiety and depression. A small study involving 20 healthy participants found that, compared to those taking a placebo, people who took a probiotic food supplement experienced fewer negative thoughts associated with sad moods. A further study showed that healthy women who ate probiotic-rich yogurt for four weeks had a reduced emotional response when shown photos of people who were fearful, angry or sad.
While these studies are encouraging, they are limited in size and scope and further studies are needed before we can draw any firm conclusions as to how and why probiotics might affect mood.
5. Careful with caffeine
Caffeine is widely accepted to be one of the most commonly used psychoactive substances worldwide and is found in a wide variety of food and drinks. In small doses, it is a performance-enhancing substance, acting on the central nervous system to delay tiredness and increase alertness. The caffeine found in tea may be beneficial for cognition in older adults, but may be problematic for those who have trouble sleeping.
Human epidemiological studies have reported better cognitive function amongst tea and coffee drinkers and a recent meta-analysis evaluating the existing evidence of caffeine and health outcomes concluded that caffeine was consistently associated with a lower risk of Parkinson’s disease, depression and cognitive disorders such as Alzheimer’s disease. However, exactly how and why this occurs is currently unclear.
Learn more about caffeine, including how it affects your body.
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Emer Delaney BSc (Hons), RD has an honours degree in Human Nutrition and Dietetics from the University of Ulster. She has worked as a dietitian in some of London's top teaching hospitals and is currently based in Chelsea.
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