How can food support our mental health?

Research is increasingly demonstrating that there is a relationship between our mood and the food we consume, which is the theme we are going to explore today, specifically looking at factors affecting our gut-brain axis (1).

Our gut microbiome communicates to our brain via the gut-brain axis, so it can exert an influence over immune and hormone signalling in our brain. Preliminary evidence in humans suggests that our gut microbiome is altered in depression. So, what can we do to support our gut microbiome? (2,3)

Mediterranean Dietary Pattern

Following a Mediterranean dietary pattern has been associated with better mental health (4). The Mediterranean diet is based on (5,6):

  • A high daily intake of plant foods, including fruits and vegetables, wholegrain, legumes and nuts.
  • Abundant use of extra virgin olive oil.
  • A moderate intake of fish, white meats, yoghurt, cheese, and eggs.
  • Low consumption of red and processed meat and sweets.

One study investigated the effect of the Mediterranean diet in 67 individuals diagnosed with Major Depressive Disorder and found remission in 32.2% in the Mediterranean diet group compared to 8% in the control group. It must be noted that this was a small sample, of whom 72% were female, so it cannot be generalised to the wider population; however, it does indicate that a Mediterranean dietary pattern may be beneficial for our mental health (7), and the results have been supported in other studies. So, let’s unpack some of the elements of the Mediterranean diet.

Oily fish

Oily fish is a good source of our essential fatty acids, like omega-3 and omega-6. Our central nervous system, which consists of our brain and spinal cord, has the second-highest concentration of lipids in our body, behind adipose tissue. Of these lipids, the brain has particularly high concentrations of omega-3 and omega-6. Research has associated low dietary omega-3 and a high omega-6 to omega-3 ratio with anxiety and depression (9). It is recommended to include one to two portions of oily fish a week, such as anchovies and salmon. If not eating fish for any reason, it may be worth talking with a registered nutritionist or dietitian and considering an algae supplement (10).


Fibre is also an important feature of the Mediterranean diet and may influence our mood by promoting beneficial bacteria in our gut microbiome, producing anti-inflammatory metabolites. These metabolites enter our bloodstream and have widespread positive effects on our health, including our mental health (11,12). Consuming a diet diverse in plant foods can help to increase our fibre intake.


Probiotics are live bacteria that, when consumed in adequate amounts, may have beneficial effects on our health (13). Preliminary research giving healthy women a fermented milk product with probiotics for four weeks found that it affected the activity of brain regions important in the processing of emotion and sensation (14). Further research found that long term administration of Lactobacilli and Bifidobacteria, strains of bacteria often found in probiotics, can have similar effects to anti-depressants on areas in our brains related to emotion and mood (15). Probiotics are not regulated, so the concentration and specific strains found in probiotics products may vary. This means labelling cannot claim that probiotics have health benefits, and further research is needed to look at this relationship (16). If thinking about taking a probiotic, talk with a registered nutritionist or dietitian.


Research finds that stress can change the composition of our gut microbiome, increasing pro-inflammatory substances (17). Therefore, trying to reduce stress may help our gut microbiome and mood. Research indicates that intuitive eating, eating based on recognising our physiological hunger and satiety cues, predicts better long-term psychology and behavioural health (18). More information about where to start with intuitive eating can be found in this article by Sophie here.


The Glycaemic Index (GI) is a rating system used for carbohydrates to show how quickly the food affects our blood sugar level when eaten on its own. High GI foods include sugar-sweetened beverages, white bread, and potatoes. Low and medium GI foods include pulses, wholegrain and some fruits and vegetables (19). It must be highlighted that the clinical significance of the GI remains the subject of debate (20).

Research has proposed that there is a relationship between the glycaemic index of food and mood. Much of the research in this area is in diabetic patients, which finds a positive association between high GI diets and depression. This research is only a correlation, so we cannot say high GI diets are causing depression, only that there is an association (21,22). However, research in different populations has found similar suggesting that high GI diets may be a risk factor for depression in postmenopausal women (23).

Importantly, this does not mean the advice is never to eat high GI foods. All foods we enjoy can have a place in our diets, and it is important to find a sustainable balance for us.


Despite research remaining in its infancy, a positive relationship between water and our mood has been suggested. This is particularly apparent in those most vulnerable to poor fluid regulation, the elderly and children (24). In contrast, when dehydration occurs, so that body mass is reduced by more than 2% (up to 60% of a human adult is water), it negatively affects our mood, increases fatigue, and decreases alertness (25). It is recommended that we drink 6 to 8 glasses of fluid a day, including plenty of water but low-fat milk, sugar-free drinks, tea and coffee all count (26)! Personally, I find always having a water bottle with me helps me make sure I drink throughout the day.


Caffeinated drinks do count towards our fluid intake and are part of a balanced diet; however, it is important to be aware that they are a stimulant. As such, small amounts can increase our awareness, mood, and perception of fatigue; however, they can increase the risk of anxiety and sleep disturbance in excess amounts. One review found 41 human studies, low to moderate caffeine intakes, between 37.5 to 450mg per day, the majority reported benefits (27).

It must be recognised that the response to caffeine varies greatly between people, and many factors affect the caffeine content of products. Health organisations generally suggest that it is safe to consume up to 300mg per day. The average cup of tea contains 11mg, and coffee contains 90mg, depending on how it is made. Green tea, chocolate and even decaffeinated coffee all also contain varying amounts of caffeine (27,28,29)!

The NHS recommend that pregnant women consume no more than 200mg, or 2 cups, of caffeinated coffee a day. This is a safe limit set as more than 600mg per day during pregnancy has been linked to insomnia, irritability, nervousness, upset stomachs and increase blood pressure (27,28,29).


  • British Dietetics Association. Food and mood: Food Fact Sheet (30).
  • National Health Service. What is a Mediterranean Diet? (31)
  • Mind. Food and Mood (32).

Overall, the relationship between food, mood and mental health is complex, with many factors to consider. A diet that provides us with adequate amounts of all the nutrients and which we feel good eating, satisfying our personal dietary preferences, is likely to support a good mood. More research is needed to understand the mechanisms that link food and mental well-being and determine how nutrition can support our mental health (1).

Please contact a registered nutritionist or dietitian for further support if you need it.


Contribution by Emilia Fish, ANutr



How can Nutrition Support our Brain Health?

Our brains are the most powerful, metabolically active organs in our bodies as they use an astonishing 20% of our overall daily energy produced by the body (1) . However, it isn’t always a common thought to think to ourselves about how best we can look after and provide high quality and nutritious foods to our brains in order to optimise our brain health.

Here we will uncover the research behind nutrition, diet and brain health as well as the role food can have on our mood and mental health.

Omega 3 and 6 fatty acids

Previous research has shown that a range of specific nutrients can have an influence on our brain function and health. When breaking down the brain into its nutritional parts, fats also known as lipids form a large proportion (nearly 60%) of the brain and they determine the brains function and performance (3).

Both Omega 3 and 6 fatty acids are essential in the body ie our bodies cannot make them and therefore they must be obtain from foods.

Omega 3 fatty acids are crucial to the development and maintenance of cell membranes in the brain. In particular, DHA is an omega 3 fatty acid that is essential for the growth and functional development of the brain in infants and it is also required for the maintenance of normal brain function in adults (4). The strongest evidence for the role of specific nutrients on brain health is with omega 3 fatty acids. They have been shown to be associated with the prevention of degenerative brain conditions and cognitive decline including dementia and Alzheimer’s disease due to their role in reducing low-grade inflammation in the early stages of neurodegenerative disease (5).

Sources of omega 3 fatty acidsconsisting of EPA and DHA include

  • Nuts and seeds including walnuts, chia seeds, flaxseeds,
  • Oily fish including salmon, mackerel, herring, sardines, kippers and trout
  • Plant oils including flaxseeds oil, soybean oil and canola oil

In addition to the beneficial fats for our health, long-term consumption of other types of fat including saturated and trans fats may compromise and have detrimental impacts on our brain health (6).


A variety of micronutrients have been shown to support brain function and cognition (7). Anti-oxidants found in a range of fruits, vegetables, nuts, seeds and legumes can strengthen our brains to fight off free radicals which are molecules produced when your body breaks down food or when you have been exposed to tobacco smoke or radiation. These free radicals can cause oxidative damage ie destroy brain cells. However, antioxidants have been shown to delay or reduce age-related cognitive decline caused by free radicals, prolonging our brains health and longevity (7).

Antioxidant rich sources of foods include:

  • Oranges, kiwis, strawberries, lemons, peppers which are rich in vitamin C and flavonoids and raspberries and blueberries
  • Artichokes and coloured vegetables including red peppers, red cabbage, spinach, beetroot, kale containing lutein
  • Nuts, seeds and legumes including pecans, pumpkin seeds and beans

B-vitamins consist of eight essential dietary micronutrients that work closely together and form an essential component of brain function (8).

It is interesting to note that a dietary deficiency of B-vitamins during critical periods of development can result in permanent changes to the brain (9), highlighting the importance of B-vitamins for brain function.

Without these vital micronutrients including vitamins B6, B12 and folic acid, our brains are more susceptible to brain disease and mental decline (8).

Dietary sources of folate include:

  • Leafy green vegetables, fruit, legumes, fortified cereals

Dietary sources of B-vitamins B1, B3 & B12 include:

  • Wholegrains, meat, fish, eggs and dairy.

Trace amounts of minerals and vitamins including iron, copper, zinc and selenium, iodine, vitamin A and choline are also fundamental to brain health and early cognitive development (10).

Dietary Patterns of the Mediterranean Diet and Mental Health

However, single nutrient trials and their effects can often be limited as we consume wholefoods and not single nutrients.

Recent and emerging evidence has delved into the impact of dietary patterns on our mental health and has found strong evidence for a potential benefit of a Mediterranean style diet in the aid of treatment for depression.

This ‘low MED diet’ included the consumption of wholegrain, vegetables, fruit, legumes, low fat dairy, fish, chicken and olive oil and emphasised reducing sweets, refined cereals, fast/fried food and sugary drinks. Results of this study demonstrate that the dietary intervention group consuming a Mediterranean style diet showed significantly greater improvements in symptoms of depression after 12 weeks when compared with the social support group (11).

In regards to Omega-3 fatty acids and our mental health, patients with depression and mental health disorders have been found to have low-levels of Omega-3 fatty acids in their blood and omega-3 fatty acids have been previously used as the basis for treatment in patients with mood disorders (12)(13). Therefore, another study has shown that healthy dietary changes through Mediterranean style diet supplemented with fish oil can improve mental health in people with depression (14).

It must be noted that depression is a mental health disorder that can be caused by various factors. However, this research does provide the first sign of evidence that improving our diets and nutrition can provide an effective treatment option alongside current treatments for depression including medications and psychotherapy.

Food and Mood

The common term ‘Food and Mood’ evolved from the idea that food can affect our brains emotional and mental state.

Mental health is defined by the World Health Organization (WHO,2014) as a ‘state of well-being in which every individual realizes his or her own potential, can cope with normal stresses of life, can work productively and is able to make a contribution to her or his community’ (15). Essentially, mental health disorders are experienced as problems with emotions, behaviours, thoughts or perceptions. Anything that affects how your body functions will affect how your brain functions. The foods that we eat can impact on the way we feel. Drinking a cup of coffee or glass of wine can make us feel good, sleepy or drowsy, providing a clear example as to how particular compounds and combinations of compounds in foods can impact our brain and mood.

When looking at how certain nutrients can have an impact on our mood however, the process is usually slower and occurs gradually.

In particular, protein and amino acids have been associated with our mood and behaviour. Amino acids which are the building blocks of protein can directly impact the conversion of neurotransmitters which are chemical messengers in the brain that can influence brain function and mood(16).

The complex combination of nutrients in foods that we consume can stimulate our brain cells to release mood altering norepinephrine, dopamine and serotonin hormones. Therefore having a diverse, nutrient dense diet could provide beneficial effects to our mood and emotions.

The main source of energy for the brain is glucose which is required to fuel physiological brain function, generation of neurotransmitters and the maintenance of brain cells (17). High quality carbohydrates including wholegrain sources and low glycaemic index (GI) foods can reduce a spike in blood sugar levels and thus changes in mood.

Sources include:

  • Wholegrains, beans, legumes and plant-based foods to provide enough fibre to your gut microbiome.

Lastly, it is not only nutrition which has been shown to be strongly linked with our brain health, other lifestyle factors are also highly involved too.

The role of the gut-microbiota and immune system has been linked to mental health also. IBS is a disorder of the gut-brain axis. Stress is one of the diagnostic criteria for IBS which can increase stress hormones, impact gut microbiome, increase the speed at which food moves through your gut and an individual’s perception of pain in the gut. Therefore, psychological stress can have physiological effects on the body. Addressing stressful stimuli could help improve IBS symptoms.



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Contribution from Emily Stynes Nutritionist