Food and mood

Food, mood and mental health

Can food really affect my mental health?

Many people are seeking to take control of their mental health using self-help, and to find approaches they can use alongside, or even instead of, prescribed medication. One self-help strategy is to make changes to what we eat, and there is a growing interest in how food and nutrition can affect emotional and mental health.

Scientific evidence to back this up is developing, but there are many challenges for scientists to overcome and, in the meantime, some medical practitioners remain unconvinced of the link between food and mood. Nevertheless, positive responses from individuals who have made changes to their diet confirm the importance of food and nutrition for maintaining or improving their emotional and mental health.

In addition to self-help, experienced healthcare professionals may support individuals in making dietary changes, and recommend appropriate nutritional supplementation. The real effects of food on mood demonstrate how it can form part of a more holistic approach to the treatment of mental distress.

I forgot about my mood swings — they have almost disappeared.

How does food affect mood?

There are many explanations for the cause-and-effect relationship between food and mood. The following are some examples:

• Fluctuations in blood sugar levels are associated with changes in mood and energy, and are affected by what we eat.
• Brain chemicals (neurotransmitters, such as serotonin, dopamine and acetylcholine) influence the way we think, feel and behave. They can be affected by what we've eaten.
• There can be abnormal reactions to artificial chemicals in foods, such as artificial colourings and flavourings.
• There are reactions that can be due to the deficiency of an enzyme needed to digest a food. Lactase, for instance, is needed to digest lactose (milk sugar). Without it, a milk intolerance can build up.
• People can become hypersensitive to foods. This can cause what are known as delayed or hidden food allergies or sensitivities.
• Low levels of vitamins, minerals and essential fatty acids can affect mental health, with some symptoms associated with particular nutritional deficiencies. For example, links have been demonstrated between low levels of certain B-vitamins and symptoms of schizophrenia, low levels of the mineral zinc and eating disorders, and low levels of omega-3 oils and depression.

What's the psychological relationship?

It's generally accepted that how we feel can influence what we choose to eat or drink (mood to food). What is less well known is how what we eat can affect our mental functioning (food to mood). The use of caffeine is one example of a complex relationship. Caffeine, found in tea, coffee, cola drinks and chocolate, is probably the most widely used behaviour-modifying drug in the world. We often choose to drink it if we are feeling tired and irritable, because it can give us a boost and help us to concentrate. Having a cup of coffee or tea also has a lot of positive psychological associations. We meet a friend for 'coffee and a chat' or give ourselves a break by sitting down with a cup of tea, and these things are very important. But too much caffeine (which is a different amount for each of us) can cause symptoms, such as anxiety, nervousness and depression. Any exploration into food and mood needs to take into account this two-way relationship and include the psychological aspect behind what we are choosing to eat.

Relating diet to mental health

How do I find out if food is affecting my mental health?

Before investigating the specific foods that could be affecting your mental and emotional health, it's well worth having a look at what you are already eating and drinking. Usually, the most reliable way of doing this is to keep a food and drink diary every day, for about one week. It seems to work best if you can write down what you eat and drink, at the time you have it. The more information you include in your diary, the more useful it is likely to be; for example, you could also note down the time and the approximate amounts you consume. People are often surprised when they look back over what they have eaten. Greater awareness is an important first step forward.

What should I look for in my diet?

A fundamental thing for you to consider will be: is there any one food or type of food that I eat nearly every day or in particularly large amounts? The basis of a healthy diet is about achieving a balance between a wide variety of foods, where the variety is spread out over a number of days. Certain foods are eaten on most days, by most people, perhaps because they are generally considered healthy to eat. Unfortunately, these can be the very foods that are having a disguised, yet disabling, influence upon your health.

It's often a combination of eating too much of some foods and not enough of others that is contributing to symptoms such as depression or anxiety. An essential part of making changes to your diet involves making sure you are not going without the nutrients your body requires on a daily basis. So, if you cut down on one food, you will usually need to substitute something similar to eat, instead. This may mean, for example, replacing wheat-based bread with bread made from rye flour.

Choosing foods

Which foods affect which moods?

Although the precise cause-and-effect relationship between different foods and moods has yet to be fully understood, many people have found they can link eating (or not eating) certain foods with how they feel. The foods and drinks that most often cause problems are those containing alcohol, sugar, caffeine, chocolate, wheat (such as bread, biscuits, and cakes), dairy products (such as cheese), certain artificial additives (or E numbers) and hydrogenated fats. Other commonly eaten foods, such as yeast, corn, eggs, oranges, soya and tomatoes, may also cause symptoms for some people, sometimes.

Significant improvement to a wide range of mental health problems can result from making changes to what we eat. There have been reports of improvements in the following: mood swings, anxiety, panic attacks, cravings or food 'addictions', depression (including postnatal depression), irritable or aggressive feelings, concentration, memory difficulties, premenstrual syndrome (PMS), obsessive-compulsive feelings, eating disorders, psychotic episodes, insomnia, fatigue, behavioural and learning disorders, and seasonal affective disorder (SAD).

Which foods do I need to eat in order to feel well?

The most vital substance for a healthy mind and body is water. It's easy to overlook drinking the recommended six to eight glasses, per day, which is a low-cost, convenient, self-help measure that can quickly change how we feel, mentally as well as physically. Having a minimum of five portions, daily, of fresh fruit and vegetables (organically grown, if possible) provides the nutrients needed to nourish mind and body (one portion equals about a handful).

It's best not to skip breakfast, to keep regular meal times, and to choose foods that release energy slowly, such as oats and unrefined wholegrains. It's also important to eat some protein foods, such as meat, fish, beans, eggs, cheese, nuts or seeds, every day. As well as providing nutrients, these eating strategies help smooth the negative effects of fluctuating blood sugar levels, which include irritability, poor concentration, fatigue, depression and food cravings. Essential fatty acids, particularly the omega-3 type found in oil-rich fish, such as mackerel and sardines, linseeds (flax), hemp seeds and their oils, are vital for the formation and healthy functioning of the brain. Other seeds and nuts, such as sunflower seeds, pumpkin seeds, brazil nuts and walnuts, also contain important 'good mood' nutrients.

Changing diet and getting help

How can I go about changing my diet?

It's probably a lot easier if you start by making changes slowly, one at a time, and just for a trial period. Changing what you eat takes a bit of effort and time; trying out new and different foods may mean you need to shop in new places. Hopefully, you will enjoy making these changes and find them to be a positive experience. Smaller changes, introduced one at a time, are easier to manage and keep up, should you find them beneficial. If you make more than one change at a time, then you won't be able to tell what is having an effect. Some changes may even be unnecessary, although you won't know until you try. This step-by-step approach can be broadened out later, and keeping a food and mood diary may be helpful.

Sometimes, a change to the diet produces some unpleasant side effects, for the first few days only. If people suddenly stop drinking coffee, for instance, they may get withdrawal symptoms, such as headaches, which then begin to clear up after a few days, when they start to feel much better. Symptoms such as these can be reduced if you cut down gradually, rather as if you were weaning yourself from a drug. There are, necessarily, some costs associated with making changes to what you eat, but these can be rewarded by significant benefits to mental and physical health.

Can I get help?

The best way to improve your health through diet is with the help of a healthcare professional experienced in treating mental health problems this way - this will usually be a dietician or a nutritional therapist.

Dieticians are qualified to manage medical conditions and health through diet, and are fully regulated by the Health Professions Council (HPC). They work in the NHS or freelance: you may be able to get a referral from your GP or other medical professional involved in your care if they think it necessary and it is available in your area; if not, you can find a local freelance dietician. 

Nutritional therapists tend to have a more holistic approach to treatment and may focus on your overall health and not just one individual problem you may be experiencing. Although nutritional therapists usually work privately, some patients with chronic conditions may receive a referral from their GP. To find local nutritional therapists visit the British Association for Applied Nutrition and Nutritional Therapists (BANT) website. Note: nutritional therapists do not need to be registered with the HPC to practice, though there is some regulation via the Nutritional Therapy Council (NTC). However, although only practitioners with qualifications from accredited courses can become members of the NTC, registration is voluntary.

General diet and healthy eating advice may also be available from your local Food for Health Advisor or Community Nutritionist. These services may not be available in your area but you can find out more about these and any healthy eating projects at your local GP surgery.

Are nutritional supplements a good idea?

The best source of vitamins and minerals is from a balanced and varied diet of health-supporting foods; however, you may need to supplement your diet with extra nutrients. It's important to get the correct balance between different vitamins and minerals, and to avoid taking any one nutrient in excess. Nutritional therapists are trained to advise on the use of supplements, and can recommend safe levels of supplementation for individual needs.

If it's not possible to get this help, many people benefit from taking a good-quality multivitamin and mineral supplement. Regularly taking a fish oil supplement or a vegetarian oil blend containing 'omega-3' oils is also beneficial. Health food shops, pharmacists and supermarkets sell nutritional supplements. You might get some on prescription.

Interactions with medication and allergies

Can foods interact with medication?

Some people like to try herbal alternatives, such as St John’s wort (Hypericum perforatum), which can help with the symptoms of depression. However, if you are already taking any medication, it’s essential that you consult your doctor for guidance prior to trying herbal remedies: some can interact with other drugs, stopping them working or causing additional adverse effects. Note: it is very unwise suddenly to stop taking any medication you are already prescribed. It’s also worth consulting a medical herbalist about using these herbs, as they don’t suit everyone.

The MAOI (monoamine oxidase inhibitor) type of antidepressant can interact with a naturally occurring substance in some foods called tyramine. This can cause a dangerous rise in blood pressure, which may be signalled by a throbbing headache. Foods containing particularly high levels of tyramine include: beans, yeast extract, meat extract, most cheeses, fermented soya bean extract and salted, smoked or pickled fish (especially pickled herring).

As the action of bacteria on protein produces tyramine, if you take MAOIs, you should avoid stale food or food that may be 'going off'. This is particularly relevant for protein-rich food, such as meat, fish or chicken. Avoid game meats completely. You can obtain a full list of tyramine-containing foods from your doctor, dietitian or nutritional therapist.

What about allergies and allergy tests?

You will probably already know if you have any classic allergies to foods, because the effects will be very quick and probably quite dramatic. However, it's possible to have some delayed or hidden food allergies or sensitivities that are less obvious, but which, nonetheless, can be detrimental to your health. The good news is that unlike classic food allergies, which tend to stay, this type of sensitivity can be improved and need not be a severe or life-long condition.

Tests for classic food allergies are unlikely to identify the foods associated with delayed or hidden allergies or sensitivities. Private allergy testing may do so, but this is often expensive. Another option is a special diet called the elimination and challenge diet. This is when you cut out a food, completely, for about two weeks (elimination stage), and then reintroduce it (challenge stage). A strong reaction to a food that you have been avoiding confirms the body's dislike of that food, and can therefore be used to diagnose food sensitivities. This method is almost certainly best tackled with the support of a healthcare professional experienced in elimination diets, who will be able to advise you on the complete range of foods you will need to avoid and substitute. A rotation diet, where you eat different foods on different days, may be recommended.

During the elimination stage, because you are giving your body a prolonged rest from a food, you may go through a withdrawal phase and experience some unpleasant, but bearable, discomfort. You will then be in a state of heightened sensitivity to that food. If you eat it (either on purpose or accidentally), you may have an exaggerated response to it, which some people find difficult to deal with. An experienced healthcare professional will be able to provide essential guidance on these aspects.

It's also possible to have a delayed reaction to a food challenge. This is when the food provokes symptoms that only manifest themselves several hours later. If you aren't aware of this possibility, then it's easy to miss them or not to associate them with the food you have been eating. Again, this is where professional help can be invaluable. Indeed, it is recommended that you consult a healthcare professional before making any major changes to your diet.

Useful contacts

Action Against Allergy (AAA)
PO Box 278, Twickenham, Middlesex TW1 4QQ
helpline: 020 8892 2711
w: www.actionagainstallergy.co.uk

Allergy UK/British Allergy Foundation
helpline: 01322 619 898
w: www.allergyuk.org
Online chat facility also available

beat
adult helpline: 0845 634 1414
youthline: 0845 634 7650
w: www.b-eat.co.uk
Charity for people with eating disorders and their families

British Association for Applied Nutrition and Nutritional Therapy (BANT)
T: 0870 606 1284
w: www.bant.org.uk
To find a nutritional therapist

Food for the brain
T: 020 8788 3801
w: www.foodforthebrain.org
Educational campaign promoting the link between food and mental health

The Hyperactive Children's Support Group (HACSG)
71 Whyke Lane, Chichester, West Sussex PO19 7PD
T: 01243 539 966
w: www.hacsg.org.uk

Freelance dietician
www.freelancedietician.org
Part of the British Dietetic Association

HPC-UK
www.hpc-uk.org
Check if your health professional is registered

Mental health foundation
www.mhf.org.uk/campaigns/food-and-mental-health

Nutritional therapy council
www.nutritionaltherapycouncil.org.uk

Sustain
www.sustainweb.org
The alliance for better food and farming

Published 2010
To be revised 2013
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