Nutritional psychiatry: Food and mood

Dr Linia Patel (PhD, RD) looks at how what you eat affects the brain.

Think about it. Your brain is amazing. Not only does it look like a giant walnut but it’s the only organ that managed to name itself! It also takes care of your breathing, your heartbeat, your senses, your movement, your thoughts and your mood. This means it is a pretty good idea to try and look after it. What you eat directly affects the structure of the brain as well as the hormones that send messages to your brain and, ultimately, your mental wellbeing.

Hormones, mood and food – the connection

What you eat directly affects the structure and function of your brain and, ultimately, your mood. However, in recent years, the focus on food and mood has been indirect. More specifically, through the gut-brain axis. Key players in this axis are your gut bacteria. They not only determine how well you absorb nutrients from your foods, but they limit inflammation, activate neural pathways that travel directly between the gut and the brain, and determine quantities of mood-regulating hormones such as serotonin and dopamine that are produced.

Here are the key hormones linked with mood and how food can impact on them.

Serotonin is linked to mood regulation and is known to be a key factor in overall mental health. It is your ‘feel-good’, happy hormone. Low levels of serotonin can cause depression, anxiety, insomnia and other mental health conditions. Having consistent levels of serotonin is vital for keeping a stable mood. Certain nutrients like tryptophan (an amino acid), vitamin B6 and magnesium are involved in the production of serotonin. The highest sources of tryptophan include eggs, salmon, cheese, pineapple, tofu, nuts, seeds and turkey. While tryptophan-rich foods may influence your serotonin levels, they must be paired with healthy carbohydrates to make a stronger impact. More carbs mean more insulin. More insulin results in more tryptophan staying in the blood, which gives you a real serotonin boost.

Dopamine is linked to pleasure, motivation and reward. When dopamine is released in large amounts, it motivates you to repeat a specific behaviour. On the other end, low dopamine levels are linked to reduced motivation and decreased enthusiasm for things that should be exciting. While dopamine levels are typically well regulated within the nervous system, what you eat can naturally increase your levels. Foods like almonds, avocado, chicken and eggs are all rich in amino acids called tyrosine and phenylalanine, which are the building blocks for dopamine. Lifestyle factors are also important. Getting enough sleep, movement, meditating and spending some time in the sun also all boost dopamine levels.

Cortisol is one of the body’s stress hormones. Everyone has high cortisol levels from time to time; however, chronic stress can lead to weight gain, a supressed immune system and fatigue, as well as anxiety and depression. A way to dampen cortisol levels is to maintain stable blood glucose levels by eating healthy, balanced and regular meals. Other nutrients including vitamin C, B vitamins and magnesium are all involved in regulating cortisol production and reducing its impact on mood. Foods like citrus fruits, leafy greens, wholegrains and nuts are all good sources of these nutrients.

Oestrogen and progesterone. These two hormones are the main female reproductive hormones; however, they also play a role in mood and emotions. The research suggests that oestrogen appears to be a protective agent in the brain. It also appears to have direct impacts on dopamine and serotonin levels. This may explain why some women feel worse in terms of their mood in the low-oestrogen phase of their monthly cycle and struggle with mood in the perimenopause. Supporting oestrogen levels means eating enough essential fatty acids such as omega-3 fats found in fatty fish (i.e., salmon and mackerel) or plant-based sources like seaweed, flaxseed and walnuts.

A good mood diet?

Interestingly, while research shows there is no specific diet that is best for mental health, there are some overall dietary patterns that appear to be better than others. When compared to a typical Standard American Diet (SAD diet) or a ‘Western’ diet, studies show that people eating ‘traditional diets’ such as the Mediterranean diet – or any traditional diet for that matter – have a 25-35% lower risk of experiencing depression. Researchers suggest this difference is because the Western-type diets tend to be higher in processed and added sugar, whereas traditional diets tend to be high in whole, unprocessed foods and generally in higher in fibre foods.

Five top good mood foods

Asparagus is one of the top plant-based sources of tryptophan (the amino acid that makes us chilled out). It’s also packed with high levels of folate, which is a nutrient linked to better mood.

Oily fish such as pilchards, mackerel and salmon are rich in tryptophan and omega-3 fatty acids as well as B12 and B6 which support the body to produce serotonin. Essential fats also reduce inflammation, protecting the nerves in your brain.

Beans and lentils are high in fibre and plant-based protein but contain several feel-good nutrients too. They are an excellent source of B vitamins, which may help improve mood by increasing levels of neurotransmitters like serotonin or dopamine, all of which are important for regulating mood.

Dark chocolate (70% and above) is rich in many mood-boosting compounds. The antioxidants it contains boost mood naturally and the presence of N- acylethanolamine chemicals stimulates the brain to release endorphins – the happy hormones.

Nuts and seeds (particularly almonds, cashews, walnuts, pumpkin, sunflower and sesame seeds) are high in tryptophan, zinc and selenium, which may support brain function and lower your risk of depression.

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About the author

Dr Linia Patel has a BSc degree in biochemistry and physiology and has recently achieved a PhD in public health. Linia is a leading dietitian and sports nutritionist. Her passion is translating nutritional science into easy-to-digest and practical advice.

References

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BDA Food and Mood Factsheet. Accessed on 6 June 2023. https://www.bda.uk.com/resource/food-facts-food-and-mood.html