Food for Thought: How the food we eat affects the brain
- Ashlee Anthony
- Jan 12
- 4 min read
By Ashlee Anthony
Mens sana in corpore sano-
‘A healthy mind in a healthy body’
The brain may appear wrinkly and unattractive to the eye, yet it is one of the most complex and fundamental systems in the scope of human life. Whilst acting as a conductor for thought, emotions, memories and cognition, it also controls every process that regulates our bodies- a feat unmatched by any other biological system! Therefore it is necessary to adapt a healthy lifestyle that will ensure optimal brain function for as long as possible. Amongst the vast number of environmental factors influencing the brain, diet plays a significant role in supporting the brain’s physical and psychological health.
How does the food we eat contribute to the brain? The NHS recommends a balanced diet following the Eatwell Guide, which states that we should aim to eat 5 portions of fruit and vegetables daily - commonly known as ‘5-a-day’. Promoted on various grocery items and encouraged by multiple organisations, the Eatwell Guide provides a simple guideline to meet the daily nutritional targets.
Additionally, according to the guidance, the vitamins, minerals and antioxidants are vital to building and maintaining brain structures and intercellular connections, and preventing oxidative stress, which can damage cells and tissues. One example includes zinc, which is essential for the formation and migration of neurons as well as the development of neuronal synapses. A deficiency could cause neurodegenerative and cognitive decline disorders, including impaired learning and memory. Surprisingly - the total amount of zinc in the body is only 1.5g for women but 2.5g for men.
Similarly, folate (vitamin B9) is important in maintaining the lipids composition in neuronal and glial membranes, which are on the border of the central nervous system. A deficiency could cause a loss of these cells which may also lead to neurodegenerative diseases, or impact more general brain functions causing changes in mood, sleep, and irritability.
Another lesser-known fact about the brain is that it requires exceptionally high energy demand. Although the brain only accounts for about 2% of our body weight, it uses almost 20% of the energy released from glucose to function. This is primarily due to the constant neuronal communication, which continues even during sleep. When a particular task requires a specific area of the brain, the energy consumption in that area will increase, by up to 8%. For example, when engaging in a conversation, the Broca area - located in the frontal lobe of the dominant hemisphere - becomes more active. However this increase is relatively minor, compared to the substantial amount of energy needed to maintain the brain's baseline activity.
The brain’s preferred source of energy comes from carbohydrates such as potatoes, wholegrains, fruit, rice, vegetables and lactose (sugar found in milk). Unlike muscle cells, the brain lacks energy storage to rely on during shortages, meaning that oxygen and glucose must be constantly supplied. If glucose fails to reach the brain due to a disruption in blood supply, neurons will quickly shut down, leading to brain death.
Another interesting relationship between food and the brain is induced eating patterns. For example, why do you feel yourself reaching for that sixth slice of cake? The neural systems responsible for food consumption and foraging also account for drug-seeking and self-administration. It raises the possibility that some foods, like certain drugs, can be addictive. This is commonly seen with sugar consumption, which is known to trigger dopamine, a neurotransmitter associated with pleasure, reward and motivation. It also activates the opiate receptors, which regulate pain, reward and addictive behaviours. Consistently high sugar consumption strengthens the neural pathways that stimulate both of these, causing the brain to crave even more sugar.
Another way the foods consumed affect mental health is through its effect on neurotransmitter serotonin, which helps to regulate sleep, appetite, moods and pain. Fun Fact: 95% of the serotonin in your body is produced in the lining of your gastrointestinal tract, which contains several million nerve cells. Only around 10% is produced in the brain. These neurons in the gut and the process of serotonin production are heavily influenced by the intestinal microbiome, made of billions of ‘good’ bacteria that enhance nutrient absorption and activate neural pathways that directly link the brain to the gut. This means nurturing your intestinal biome with whole, unprocessed foods and probiotic foods can be reflected in your mood and energy levels.
The above examples are just a few ways of how our diet influences the brain. The key is to find a healthy balance that doesn’t over restrict but allows you to gain the benefits from a variety of food options, keeping you as happy and healthy as possible. The balance between mental and physical health is also paramount: the occasional treat is not only desirable but necessary to ensure consistency in the long term. If you wish to receive more guidance on building a balanced diet, the following link to the NHS website provides the relevant information:
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