Diet and mental health

Most people are aware of the link between what they eat and their physical health – after all, having a nutritious and balanced diet is arguably among the best ways to stay well. But what about your mental health and well-being?
 
Can what you eat increase your chances of having good mental health too? Does eating certain foods help improve your sense of well-being and mood? And can eating certain foods also have a negative impact on your mental health, making you feel tired, stressed and even depressed?
 

How does nutrition affect mental health?

There is an increasing understanding that nutrition and mental health are indeed linked. For instance, researchers now believe nutrition can play a big part in the development as well as the severity and duration of depression, and that diet is linked with human cognition, behaviour and emotions (i). 

More specifically, having low levels of certain nutrients in your diet – including some vital vitamins, minerals and omega-3 fatty acids – is thought to contribute to the development of several mental disorders. Scientists also suggest that taking certain nutritional supplements may help reduce mental disorder symptoms (ii). 
 

Why are food and mood linked?

Scientific research into how food and mental health are linked is still at an early stage, which means there’s still a lot we don’t know about how what you eat affects how you feel emotionally. However, one theory that’s becoming widely accepted is that the two are linked as a result of the human gastrointestinal system being directly connected to the human brain. 
 

The gut-brain axis

Sometimes called the  gut-brain connection, the gut-brain axis is a  relationship that involves the gut microbiota – the 100 trillion or so living micro-organisms including bacteria that live in the gut. One of the gut microbiota’s roles is to make certain chemicals that interact with and carry messages to your brain, such as serotonin and dopamine (according to Harvard experts, 95 per cent of your serotonin is produced in your gastrointestinal system (iii)). These chemical messengers (or neurotransmitters) help regulate a number of different functions, including sleep, mood and emotion. 

It’s commonly accepted that what you eat can make a difference to the health of your gut microbiota – eating nutritious foods, for instance, is believed to help your beneficial micro-organisms thrive. This has widely accepted implications for your digestive health, but now it’s also thought that one of the advantages of a healthy gut microbiota is that it helps support a healthy mental and emotional state.
 
Indeed, according to the Mental Health Foundation, eating well can make you feel better and improve your sense of well-being and mood (iv). The mental health charity Mind also claims eating more healthily may not just improve your mood but also give you more energy and help you to think more clearly (v).
 

What is a healthy diet? 

Eating to boost your mental well-being  doesn’t have to be complicated. One of the most established guides to eating healthily here in the UK is the Eatwell Guide, which was developed by Public Health England to represent the government’s recommendations on eating healthily and having a balanced diet. 
Dietary suggestions within the Eatwell Guide include the following:

• At least five portions of a variety of fruit and veg every day to provide a range of vitamins, minerals, fibre and other valuable nutrients. These can include fresh, frozen, tinned, dried or juiced foods (though it’s recommended to limit yourself to no more than 150ml of fruit juice or smoothies a day). 

• Starchy foods – preferably higher-fibre wholegrain varieties (potatoes with their skins on, wholewheat pasta and brown rice, for instance). These should make up just over a third of the food you eat in general, as they are important for your energy levels and contain a range of nutrients. 

• Some dairy or dairy alternatives (ideally lower-fat varieties) to provide protein and calcium for healthy teeth and bones.

• Some non-dairy proteins  such as fish, poultry and lean meats, and plant-based sources of protein such as beans, peas and lentils. You should also aim to eat at least two portions of fish each week, one of which should be oily. If, however, you don’t like eating fish you could try high-strength fish oil or a vegan omega-3 supplement (see below for more details).

• Small amounts of unsaturated fats such as vegetable, olive, rapeseed and sunflower oils and spreads.

• Small amounts of food that are high in fat, salt and sugar such as chocolate, biscuits, cakes, sugary drinks, butter, ghee and ice cream (these should be only eaten occasionally). 

• Plenty of fluids such as water and other sugar-free drinks, lower-fat milk , tea and coffee (around six to eight cups or glasses a day).

The Mediterranean diet – which includes high amounts of fruit, vegetables, nuts and legumes; moderate amounts of poultry, eggs and dairy products; and only occasional amounts of red meat – has also been linked with better mental health, with researchers finding it may be associated with a reduced risk of depression (vi). 
 

The best foods for mental health 

There are lots of things you can do to change your diet and eating behaviours with a view to improving or maintaining your mental well-being . Making these changes, however, isn’t always easy – especially if you do have a mental health problem – so it’s a good idea to adopt a gradual approach and make small changes one by one rather than trying to improve your entire diet overnight.

Some of the ways you could eat and drink more healthily to improve your mental health include the following:

Eat for good gut health   If the gut-brain axis theory of how foods affect your mental well-being  is correct, then it may pay dividends to eat foods that support your gut microbiota. Foods that are widely thought to help keep your gastrointestinal system healthy include fruit, vegetables, beans, legumes, whole grains and fermented foods such as live natural yoghurt, sauerkraut, apple cider vinegar, kefir, kombucha and kimchi. Meanwhile, supplements that may help support gut health include inulin, fructo-oligosaccharides (FOS), beta glucans and live bacteria (probiotics) such as acidophilus capsules. 

Drink plenty of fluids   Having six to eight cups or glasses of fluids a day isn’t just good for your physical health – it can keep you mentally healthy too That’s because if you don’t drink enough, it can be hard to stay focused or to concentrate. Most drinks count towards your daily quota, but try to avoid drinks with lots of sugar or caffeine (some caffeine is usually fine, just try not to overdo it). 

Eat healthy fats   Unsaturated fats help keep your brain working well, so try to use oils and spreads that contain vegetable oil, olive oil, rapeseed oil and sunflower oil instead of butter or lard. You can also eat foods that contain healthy fats such as nuts and seeds – though be aware that these foods tend to be high in calories, which means you should eat them in smaller portions to maintain a healthy weight. 

Have some protein with every meal   Protein is one of the constituents of a healthy diet and it’s a good idea to have some with every meal because it’s made of substances called amino acids that help your body produce important brain chemicals. 

Get your 5 a day   There’s a good reason why the Eatwell Guide recommends having five portions of fruit and veg every day: these foods contain a wide variety of nutrients that help support your physical and mental health. For more information on what counts towards your daily five portions (and how much of different foods make up a portion), visit nhs.uk.

Choose whole grains   Refined carbohydrates release their energy into your body quickly, which means you get a quick energy hit followed by a slump. The problem is that if your energy level is low, your mood may plummet too. Unrefined carbohydrates – such as whole grains, for instance – release their energy more slowly, which can keep your energy level more steady. Whole grains include oats, brown rice, wild rice, barley, corn, quinoa, rye and whole wheat. 

Cut back on caffeine  Foods and drinks that contain caffeine also give you a quick burst of energy. But your energy will usually soon drop, leaving you in the longer term feeling anxious, irritated, depressed and unable to sleep if you have caffeine close to your bedtime. Caffeine is found in tea, coffee, chocolate and caffeinated soft drinks (including colas and energy drinks). You could try switching to decaffeinated versions of your favourite caffeinated drinks, or just simply drink less or no caffeine.

Processed and sugary snack foods can also make your energy levels spike and plummet, so try to only have small amounts once in a while if you have to have any at all. Healthier snacks, for example, could include fresh fruit, veggie sticks, a few nuts or seeds, a handful of edamame beans or a hard-boiled egg. Drinking too much alcohol may also have an effect on your mental well-being  by increasing anxiety – try to keep your intake at the current recommended level, which is 14 units of alcohol a week spread over at least three or four days. 
 

Practice healthy eating habits

Meanwhile, how you eat and your behaviours around food can be significant for your mental well-being  too:

Avoid skipping meals   If you don’t eat regularly it could have an effect on your blood sugar, low levels of which can make you feel down, tired and irritable. Try to stick to the same mealtimes whenever you can, having your meals at regular intervals. 

Share meals with others   Thanks to the stresses and strains of modern living fewer of us sit down to a meal with friends and family these days. But sharing your meals can have many psychological, social and biological benefits, says the Mental Health Foundation (iv). Cooking with other people can also be a lot of fun, says Mind (vii). 

Keep a food diary   Certain foods may make you feel better, while others may put you in a worse mood or keep you up at night. Finding out which foods help support your mental health – and which don’t – can be achieved by simply keeping a food diary, where you write down the contents of all your meal and make notes about how you feel during and after eating them. It could help you to identify and avoid certain foods and have more of others that you’ve found to be beneficial. 

Eat more mindfully   Many of us tend to eat without thinking about what or how we’re eating. Paying more attention to your food, including what it tastes like, how it feels in your mouth and how it makes you feel when you eat it can help you eat more healthily and enjoy your food more, both of which can help you feel better in terms of your mental health. 

Ask for support    If you find it difficult to eat well, there is help out there for you. Ask your GP if you could be referred to a dietitian or nutritionist, or find a private practitioner via an organisation such as the British Dietetic Association or the British Association for Applied Nutrition and Nutrition Therapy. 
 

What are the best vitamins for mental health? 

As well as making the above changes you may want to try adding specific nutrients and foods to your diet to help give your mental well-being  a boost. Some of the nutrients that have been strongly linked with mental health, most notably depression, and the foods that contain them include the following (viii):

Magnesium   Foods that contain this important mineral include spinach, nuts, wholemeal bread, pumpkin seeds, cocoa powder and soya milk

B vitamins   Out of all the B vitamins, vitamins B6, B12 and folic acid have been notably linked with mental health. You can find them in a variety of foods including peanuts, oats, bananas, fish, meat, poultry, soya beans, dairy foods, leafy green vegetables, broccoli, kidney beans, chickpeas, peas and fortified breakfast cereals. 

Omega-3s   These important fatty acids are also found in a variety of foods including plant-based oils, soya foods, nuts and seeds. But two omega-3 fatty acids in particular – namely EPA and DHA – are thought to be especially beneficial for human health. You can get these omega-3s from oily fish such as salmon, herring, trout, mackerel and sardines. Vegetarians and vegans can now get omega-3 supplements containing EPA and/or DHA, where the fatty acids are sourced from marine algae instead of fish. 

Zinc   Food sources of zinc include dairy foods, meat, poultry, shellfish, bread, wheatgerm and pumpkin seeds.

Iron   This is found in good amounts in foods such as oysters, red meat, liver, beans, nuts, dried fruit, cocoa powder, lentils, tofu and fortified breakfast cereals. Women of childbearing age need more iron than men and older women, and those who have heavy periods are particularly at risk of becoming deficient (for more information, read our guide to anaemia and iron deficiency).

Vitamin C   Oranges and orange juice are arguably the best-known sources of vitamin C, but you can get it in many other foods too, including berries, broccoli, red and green peppers, grapefruit and potatoes. 
 

Additional nutrients for mental health 

Two more nutrients that have been linked with mental health are iodine and vitamin D. 
 

Iodine benefits for the brain

Iodine is an important mineral that’s essential for the normal working of the thyroid gland. Some of the signs you may be deficient in iodine include low mood, poor memory and an inability to concentrate. Milk is one of the main sources of iodine for most people, but you can also get it in other dairy foods as well as fish, eggs, meat and poultry. Smaller amounts are found in nuts, bread, fruit and vegetables. Find out more in our guide to iodine.
 

Vitamin D and depression 

A lack of vitamin D has been linked with depression in a study review that included a total of more than 30,000 adult participants, with those having the lowest levels of the vitamin also having the highest risk of depression (ix).

Foods that contain vitamin D include oily fish, liver, egg yolks, red meat and fortified foods – though our main source of vitamin D is sunlight exposure. This may explain why so many people in northern hemisphere countries including the UK are at risk of vitamin D deficiency during certain times of the year. Indeed, the UK government’s Department of Health and Social Care advises everyone to consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter (x). 

Those who are also at high risk of not getting enough vitamin D during the spring and summer, however, are recommended to take vitamin D all year round (these include people who don’t go outdoors very often or whose skin is covered when they’re outside). People with dark skin may also not make enough vitamin D from sunlight and are too advised to consider taking a supplement throughout the year. 

Vitamin D supplements are widely available, with the recommended form being vitamin D3 or cholecalciferol (this is the natural form your skin makes when it’s exposed to sunlight). Vitamin D3 drops are available too, and if you’re a vegan you can also get vitamin D3 in supplements sourced from lichen (other D3 supplements are usually made from the fat of lamb’s wool, which means they’re not vegan friendly). 

Besides vitamin D you can get all of the above-mentioned nutrients in supplement form, which may be useful if you don’t always eat as healthily as you should. Many of the nutrients mentioned are also available in a good-quality multivitamin and mineral supplement. Find out more about individual vitamins and minerals, including how much you need each and every day for good health, in our guide to multivitamins and daily requirements.

 

For more information about mental health 

 
Find out more about a variety of mental health conditions in our pharmacy health library’s mental health section.
 

References

1. Sathyanarayana TS et al.. Understanding nutrition, depression and mental illness. Indian J Psychiatry 2008 Apr-Jun;50(2):77-82. Available online: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2738337/

2. Lakhan SE, Vieira KF. Nutritional therapies for mental disorders. Nutr J 2008;7:2. Available online: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2248201/

3. Available online: https://www.health.harvard.edu/blog/nutritional-psychiatry-your-brain-on-food-201511168626

4. Available online: https://www.mentalhealth.org.uk/explore-mental-health/a-z-topics/diet-and-mental-health

5. Available online: https://www.mind.org.uk/information-support/tips-for-everyday-living/food-and-mood/about-food-and-mood/

6. Lassale C et al.. Healthy dietary indices and risk of depressive outcomes: a systematic review and meta-analysis of observational studies. Mol Psychiatry 2019;24:965-86. Available online: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6755986/

7. Available online: https://www.mind.org.uk/information-support/tips-for-everyday-living/food-and-mood/about-food-and-mood/

8. LaChance LR, Ramsey D. Antidepressant foods: An evidence-based nutrient profiling system for depression. World J Psychiatry 2018 Sep 20;8(3):97-104. Available online: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6147775/

9. Anglin RES, Samaan Z, Walter SD, McDonald SD. Vitamin D deficiency and depression in adults: systematic review and meta-analysis. Br J Psychiatry 2013 Feb;202:100-7. Available online: https://www.cambridge.org/core/journals/the-british-journal-of-psychiatry/article/vitamin-d-deficiency-and-depression-in-adults-systematic-review-and-metaanalysis/F4E7DFBE5A7B99C9E6430AF472286860

10. Available online: https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-d/

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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

 
 

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