Nutrition and mental health

Written by Katherine Nicholls
Katherine Nicholls
Nutritionist Resource Content Team

Last updated 11th April 2024 | Next update due 11th April 2027

Many of us are well aware of the benefits that eating a balanced diet has on our physical health, but do you know how it benefits our mental health? More and more research is coming to light on the impact food has on both our overall mental wellness, as well as specific mental illnesses like depression and anxiety.

Here we’ll take a closer look at how food and mood are related, what role our gut health has and how a nutrition professional can support you.

Food and mood: What’s the link?

Eating a well-rounded and nutrient-rich diet can help to improve mood, increase energy levels and help you think more clearly. Several elements are at play here, from the number of carbohydrates you eat to the way deficiencies in vitamins and minerals affect mental health. Let’s start by looking at the importance of carbohydrates.

Carbohydrates and eating regularly

For your brain to be able to concentrate and focus, it needs energy. 20% of all energy needed by the body is used by the brain. This energy comes from blood glucose, and the glucose in our blood comes from the carbohydrates we eat.

When we don’t have enough energy for the brain, we can feel weak, tired and unable to think clearly. Ensuring you eat regular meals containing some carbohydrates will help with this. Alongside starchy foods like pasta and rice, sources of carbohydrates include:

  • wholegrains
  • fruits
  • vegetables
  • legumes
  • lower-fat dairy

When your blood glucose rises and falls rapidly, it can have an impact on your mood, making you feel irritable, low, and even triggering symptoms of anxiety. Keeping your blood glucose levels steady throughout the day is key. Try foods that release energy slowly like oats, cereals, nuts and seeds, and aim to eat smaller portions spaced out throughout the day. 

Proteins and fats

Alongside the energy it gets from carbohydrates, your brain needs amino acids to help regulate thoughts and feelings. As protein contains amino acids, it’s important to get enough of this in your diet. Protein is found in lean meat, fish, eggs, nuts and seeds, cheese, soya products and legumes. 

Some people may be under the impression that all fat is bad for us, but this isn’t the case. Fatty acids, like omega-3 and omega-6, are essential for our brains to function well. Healthy fats can be found in nuts, seeds, oily fish, poultry, avocados, dairy products and eggs.

Our focus on low-fat diets may have also inadvertently affected our mental well-being. The brain is around 60% fat and omega 3 fatty acids are important for neurons to communicate effectively.

- Read more on how diet affects mental wellness.

Vitamins and minerals

When we don’t get enough of certain vitamins and minerals, both our physical and mental health can suffer. The best way to ensure you’re getting enough of the vitamins and minerals you need is to eat a varied and balanced diet, rich in fruit and vegetables. For some, a supplement may be needed, but be sure to check this with your doctor or a nutrition professional.

Here are some examples from the British Dietetic Association of how different vitamin/mineral deficiencies can affect your mood:

  • Iron: A lack of iron can lead you to feel weak, tired and lethargic. Foods rich in iron include red meat, poultry, fish, beans, pulses and fortified cereals. 
  • B vitamins: Not getting enough B1, B3 and B12 can make you feel low, tired and irritable. Animal protein foods such as meat, fish, eggs and dairy, and fortified cereals are rich in B vitamins.
  • Folate: When you don’t get enough folate you can be at a higher risk of feeling depressed. Folate can be found in green vegetables, citrus fruits, liver, beans and fortified foods like marmite.
  • Selenium: A selenium deficiency may increase the chance of feeling depressed and other negative mood states. Good sources of selenium include Brazil nuts, seeds, wholemeal bread, meat and fish. 

A helpful way to make sure your diet is nutrient-rich is to ensure you’re getting at least five portions of fruit and vegetables every day.

Nutritionists who can help with mental health and well-being

Alcohol consumption

Drinking too much alcohol can affect us both physically and mentally. Some people may drink more when they are feeling depressed, stressed, or anxious. Over time, too much alcohol can weaken your immune system and bones, as well as make you more at risk of high blood pressure, stroke, cancer, sleep and sexual problems. Alcohol can also put you at increased risk of depression.

Dehydration anxiety 

Hydration and nutrition go hand in hand, but the vast amount of information available can often overwhelm us and cause feelings of anxiety. For some, these feelings can be severe.

Dehydration anxiety is a fear that you aren’t drinking adequate amounts of water. You may fear going anywhere without your water bottle. This fear can lead to high consumption of water - more than your body requires - which can lead to illness. The fear stems from not giving your body sufficient hydration to perform at its best. This chronic form of anxiety is closely linked to obsessive-compulsive disorder and orthorexia (an obsessive fixation with eating healthy and focusing on the quality/purity of food).

Signs of dehydration anxiety include: 

  • monitoring your daily intake to the litre
  • feeling a sense of dread when you don’t have your water bottle
  • worrying about where to get water from, e.g. when shopping or travelling
  • experiencing panic attacks when water isn’t immediately available

“When I went to buy a new water bottle, I had to check every one to find the largest available. I’m aware that I can feel thirst, but now I’m not sure if it’s psychological or real. If I go to London, I’m constantly thinking, ‘Can I get water?’, and ‘Is there a toilet?’. It’s a vicious circle.” 

- Alice shares her experience with dehydration anxiety and how it led to her drinking in excess of five litres a day.

Nutritional therapy and hydration

The recommended six to eight-glasses-a-day advice (approximately two litres) can be used as a general guideline for your water intake, alongside consideration of your individual dietary needs. The specific amount of hydration needed varies from person to person, so it’s important to tune into your whole lifestyle when considering how much water is sufficient hydration for you.

Nutritional therapist Karen Alexander says that it's not only the water you drink, but your diet, gender, age, exercise and lifestyle are also contributing factors to your water needs:

"Other than listening to your thirst, another way to judge your water needs is via urine colour. Ideally, you want pale yellow urine – be aware that if you are taking Riboflavin (vitamin B2) this can make urine bright yellow.

"Many vegetables contain high water content and can be counted towards your daily intake including most fruit, cucumber, celery, lettuce, courgette, tomato, potato, cabbage and even foods like salmon and eggs if not over-cooked. If your intake of vegetables and fruit is low you will need to drink more to ensure you are getting enough."

If you are concerned you’re drinking too much water, or too little, it can be helpful to speak to a nutritional therapist who can work through your hydration needs.

Where to get help for dehydration anxiety

If hydration anxiety is becoming a constant state in your life, counsellor Sophie Robinson-Matthews details some helpful tips to overcome these anxious feelings in Happiful’s ‘What is dehydration anxiety?’.

Keeping track of how much you drink can help you to reassure yourself that, even when you do not drink as much as you usually would, you are still OK. Practising breathing exercises can also help tackle dehydration anxiety when it strikes.

Gut health and mental health

The link between our gut health and our mental health is becoming clearer. Often dubbed the ‘second brain’, our digestive system produces over 90% of all serotonin (the ‘happy’ hormone) in our body. Our gut can also affect immunity and resilience to stress, which can both affect our mood. Having a healthy digestive system, in general, ensures we’re able to absorb vitamins, minerals and nutrients our brains need to thrive.

Often, when we’re feeling stressed or anxious, we’ll feel it in our gut. Digestion may speed up or slow down, depending on how we’re feeling. To keep your gut happy, ensure you eat plenty of fibre and get lots of fluid and regular exercise.

Fermented foods can give the good bacteria in our gut a boost, so try to incorporate these into your diet where possible. Other gut-friendly foods include fruits, vegetables, whole grains, beans and pulses.

A note on caffeine

Caffeine is often a go-to when you need a burst of energy, but its stimulating properties can disturb your sleep, cause headaches, and irritability, and may even trigger anxiety and depression symptoms. If you drink a lot of coffee, tea, cola or other energy drinks, you may want to try swapping them out for non-caffeinated drinks like herbal teas or enjoy decaf versions.

Medication and your diet

It’s worth noting that if you’re taking a certain medication for your mental health, there may be some foods you need to avoid. Be sure to speak to your doctor about any medications you’re taking and ask about any dietary changes you may need to make.

How can a nutritionist help?

Mental health and wellness can benefit from a holistic approach. Eating a balanced diet that contains the nutrients your brain and gut need can complement other therapies and approaches you’re using to manage mental health.

If you find yourself relying on 'comfort foods' (foods that may give you a temporary mood boost but are often unhealthy for you), working with a nutritionist may be able to help you identify alternative mood-boosting options that can help provide energy, vitamins and nutrients that your body needs.

To ensure you’re getting the right foods for your particular circumstances, it can help to seek professional support from a nutritionist. They will be able to talk to you about your needs, take into account your individual requirements and tailor a diet plan to suit you.

On the face of it, our diets may seem to be sufficient but our digestion, absorption, health history and inherited health traits can affect the amount of nutrients our body needs. One or more of these factors can tip the balance towards poor mental health. A personalised approach to diet and lifestyle can also help you regain physical and mental well-being.

- Nutritionist Sarah Hanratty.

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