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Food And Mood

The link between nutrition and mental health

Most of us would agree that eating healthy food has a positive effect on our physical health, but do you know that it can also directly benefit mental health? In a five-part newsletter series we explored the link between nutrition and mental health. Here's what we wrote:

Part one: What are the Nutritional Therapists at Julia Davies Nutrition doing to look after our mental health?

Thanks to the Coronavirus, we are all in lockdown at the moment, so what are the therapists at Julia Davies Nutrition doing for ourselves to look after our mental health?



1. Diet – I make sure to keep my gut as healthy as possible. I was diagnosed with ulcerative colitis many years ago and learned quickly how certain foods lead to flare-ups, and flare-ups lead to very low moods. I focus on eating a variety of fruits and vegetables every day, protein with every meal, oily fish a few times a week, and lots of plant-based foods to keep my intake of fibre high. I also minimise sugar and alcohol, and almost never eat processed foods. If my body is healthy, my emotions feel much more balanced and my brain is clearer and more focused.

2. Relaxation – To control stress I like to do yoga or lift weights, go for long walks, take Epsom salt baths, and do deep breathing exercises while lying on my shakti mat (it’s like a bed of nails/ acupressure mat – you get used to it quickly and it feels great!).

3. Escape – If I am ever feeling wobbly, it helps to get out of my own head for a while. I will listen to music (there’s a genre for every emotion), or to a story on my favourite podcast The Moth. Sometimes I will turn to films to either make me laugh or cry, depending on what I need at that moment.



1. Sleep - I go to bed at about 10, earlier if it has been a long day and if I have had a busy period, I put aside time in my diary on a weekend to lie in.

2. Talking - I always feel so much better when I tell someone what is on my mind or what I am worrying about. It helps me to understand myself better and to frame my concerns differently.

3. Boundaries - I always want to be a supportive listener to friends, family and clients but it is really important to recognise when you are giving away too much emotional support to others, it can exhaust you and lead to a spiral into poor mental well-being. I take regular breaks, schedule in days just for me to do something nice and ensure I have time away from phone and emails and make time for people who lift me up and make me laugh.



1. Cooking and Gardening - The challenge of home-schooling was a real struggle at first trying to keep a similar structure to what the kids are used to. But now we have evolved into me teaching the kids how to cook. We are growing our own herbs in the garden and we are very excited to receive our delivery from Rocket Gardens (a place that do the seed to sprouting process and then deliver young seedlings ready to plant). It is not the traditional teaching, but this is more engaging for my two, and they are happy which is my ultimate priority! Being outdoors makes me feel more relaxed and in control.

2. Turning off the TV - Not watching the news or mainstream TV at all! This is oddly liberating. My husband keeps an eye on things so we are not completely unaware, but on the whole there is not a whole lot of chat about COVID-19 in our house.

3. Exercising - Exercising in the form of a ‘daily mile’ run around the garden or the village as the kids do this at their school every day. We are also doing Cosmic Kids Yoga and Oti Mabuse dance classes


Part two: Gut Health

There are clear links between the gut and the brain, and it is possible for poor gut health to contribute to mental health issues. There is a bi-directional relationship between the brain and the intestines, and the two are intimately connected. Distress in the gut can be either the cause OR the result of mental health issues like stress, anxiety and even depression.

The second brain

The gut is sometimes referred to as our second brain, and although it plays no part in conscious thought or decision making, it partly helps determine our mental state, and plays a key role in certain diseases in our bodies. Technically called the enteric nervous system, the second brain is comprised of over 100 million neurons – more than are found in the spinal cord or the peripheral nervous system.

Brain to gut

We produce over 90% of all serotonin - known as the happy hormone - in our guts, and 70% of our immunity resides in our gut cells. If you have ever had butterflies in your stomach when nervous or needed to run to the loo when under stress, you will know that fear, stress, and anxiety can be felt directly in our guts. How we are feeling can impact our digestion, absorption, and elimination.

Are your stomach or digestive issues - such as reflux, pain, or diarrhoea – caused by stress? Discussing your symptoms with your nutritional therapist can help find a way to cope with lifestyle induced issues.

Gut to brain

A healthy digestive system ensures effective absorption of the nutrients in our food which our brains need to be healthy. If your gut health is compromised, it can lead to mental health issues.

Gut health can be influenced by several factors including levels of hydrochloric acid in your stomach, diet, chronic stress and lifestyle factors, and the balance of your microbiome. Bacteria in our gut microbiome can have a major influence on our moods. These bacteria produce short chain fatty acids, secrete neurotransmitters (such as dopamine, norepinephrine, acetylcholine, GABA which are responsible for mood, concentration, motivation, and anxiety), and can directly affect our immune system and inflammation levels. An imbalance between the good and bad bacteria residing in our microbiome can cause an overreaction of the immune system, contributing to inflammation, which can directly impact the brain.

Healthy Gut Foods

To keep your gut healthy, you need to maintain a good balance of beneficial bacteria in your gut. This includes consuming plenty of vitamins, minerals, and fibre, drinking plenty of water, exercising regularly, managing stress and sleep, and avoiding sugar, alcohol, high amounts of saturated fats, and processed foods.

Eating probiotic foods can boost your levels of beneficial bacteria in your microbiome, so incorporate these foods on a regular basis: kimchi, sauerkraut, kefir, kombucha, organic apple cider vinegar, tempeh, miso and plain yoghurt. The probiotic benefits are destroyed by heat and processing so be sure to look for raw, unpasteurised versions.

Prebiotic foods contain indigestible fibre which feeds the beneficial bacteria in our bodies. These include artichokes, leeks, onion, garlic, cabbage, legumes, chicory, and oats.

Probiotic supplements are widely available, but their use should be discussed with us beforehand in order to determine the best combination of bacteria and dose.

Probiotic supplements are widely available, but their use should be discussed with us beforehand in order to determine the best combination of bacteria and dose. To read more about the gut/brain axis and the role of probiotics, head over to this article Gut-Brain Axis and Probiotics on the Optibac Probiotics Learning Lab.


Part three: Carbohydrates and Mental Health

What we eat matters! Eating a healthy diet full of nutrient-rich foods can improve our mood, cognition, and energy levels.

Carbohydrates and balanced blood sugars

Twenty percent of the energy we obtain from food is used by the brain. This energy comes from the carbohydrates we eat in the form of glucose. When we do not have enough glucose, we can feel unable to focus or concentrate, fatigued, and fuzzy headed.

When we think of carbohydrates, many of us think of foods like pasta, bread, potatoes, and other starchy foods. These are what we call simple carbohydrates. These foods cause our blood glucose to rise and fall rapidly and can lead to fluctuations in mood. Low glucose levels (also known as hypoglycaemia) can lead to low mood, irritability, and even anxiety.

This rollercoaster of high blood sugar followed by low levels can exacerbate symptoms of mood disorders. Excess blood glucose can increase the risk of depression, potentially due to increased inflammation which impacts the brain, or by suppression of brain-derived neurotrophic factor (BDNF) which is a protein found in the brain and spinal cord which promotes health of nerve cells. There is also a correlation between sugar and anxiety.

There is another category of carbohydrates, known as complex carbohydrates, which includes wholegrains, fruit, vegetables, legumes, and even low-fat dairy. These foods release energy slowly, and keep your glucose levels steady instead of fluctuating, leading to a steadier mood.

Research has shown that consumption of low carbohydrate diets can lead to depression in some people, as carbohydrates trigger the synthesis of serotonin and tryptophan, which are neurotransmitters that lead to a feeling of well-being. Lower glycaemic index (GI) simple carbohydrates provide a longer lasting effect on mood, energy, and brain chemistry than higher GI simple carbohydrates.

Examples of low, medium, and high GI foods

  • Low GI foods: rolled or steel-cut oats, barley, bulgur, butter beans, peas, non-starchy vegetables, milk, sweet potatoes, most fruit

  • Medium GI foods: brown or basmati rice, couscous, wholemeal bread, rye bread, quick oats, honey

  • High GI foods: white potatoes, white bread, cookies, most breakfast cereals, instant pasta, short grain white rice, pineapple, melon

What should you eat?

Some of the best carbohydrates to incorporate into your diet on a regular basis which release energy slowly include:

  • Oats – Steel-cut and rolled oats are low GI and contain beta-glucan, a fibre with many health benefits.

  • Chickpeas – Chickpeas are a great source of protein and fibre and are low on the GI scale. They also contain calcium, potassium, and folate.

  • Carrots – Low on the GI scale, carrots also contain beta-carotene and antioxidants.

  • Kidney beans – These are rich in protein and fibre, contain potassium, and are low in fat.

  • Lentils – Low on the GI scale, lentils are rich in protein and fibre, and are a good source of phosphorus and potassium.

For more information about the glycaemic index, click here.


Part four: Proteins, Fats and Mental Health


Proteins contain amino acids. There are several amino acids which are considered ‘essential’ because we cannot synthesise these ourselves, and so we must ingest them through food. Our bodies need twenty different amino acids to function properly, and nine of these are classified as essential. Amino acids are needed for synthesis of hormones and neurotransmitters, muscle growth and repair, for regulating immune function, and more.

Neurotransmitters are chemical messengers which communicate between nerve cells and other cells in the body. They can affect a wide variety of functions including mood and sleep. For example, Gamma-aminobutyric acid (GABA) is an inhibitory neurotransmitter which plays a role in regulating anxiety and can affect feelings of calmness and relaxation. Dopamine and serotonin are made from amino acids tyrosine and tryptophan respectively, and low levels of these neurotransmitters is associated with low mood and aggression. If we do not get enough quality protein through our diet our synthesis of neurotransmitters is affected.

Foods considered to be complete proteins are those which contain all nine essential amino acids. Examples of complete proteins are red meat, poultry, fish, eggs, milk, cheese, yoghurt, tofu, tempeh, and quinoa. If you do not eat these foods but eat a variety of proteins, you will likely ingest enough amino acids to add up to a complete protein and provide the body with sufficient building blocks to make proteins.


Healthy fats are essential for our brain function. In fact, about two-thirds of the human brain is fat, and twenty percent of that is made up of DHA, a polyunsaturated omega-3 fatty acid (PUFA). PUFAs (omega-3 and omega-6 fatty acids found in walnuts, sunflower seeds, flax seeds and flax oil, sesame oil, and oily fish) play an important role in brain function, including transmission of messages, metabolism, growth, moderation of inflammation, and protection. Unbalanced or reduced supply from the diet is associated with cognitive and mood disorders.

Monounsaturated fats (MUFAs) found in olive oil, avocados, hazelnuts, almonds, and pecans benefit overall brain function. Low levels have been associated with depression-like behaviour and the development of Alzheimer’s disease.

Diets rich in healthy fats have been clinically found to reduce symptoms of depression. In a study of 166 people with clinical depression being treated with medication, symptoms were significantly improved after eating a modified Mediterranean diet (with healthy fats such as raw nuts and olive oil) for 12 weeks. Another study measuring anxiety in medical students found a twenty percent reduction in symptoms after increasing omega-3 fatty acid intake.

Over the years, fats have been wrongly demonised, causing people to seek out ‘low-fat’ versions of foods. Research shows that people on low-fat diets have a significantly higher risk of depression and other mood and behaviour disorders. A long-term longitudinal study of over 12,000 people over eleven years showed depression rates were much higher in people who ate less PUFAs and MUFAs, and who consumed higher amounts of trans fats. This same result has been shown many times in various longitudinal studies as well as randomised-controlled trials and experiments.

It is essential to eat enough healthy fat every day as part of a balanced diet. Healthy fats can be found in nuts, seeds, avocado, eggs, oily fish (salmon, mackerel, anchovies, sardines, herring), olive oil, and dairy products.


Part five: Vitamins and Minerals

Eat food, not too much, mostly plants.

Food writer Michael Pollan once famously said in a lecture to scientists at the Centers for Disease Control and Prevention that everything he learned about eating could be summed up in those seven words: "Eat food, not too much, mostly plants."

In modern day diets, many people are over-fed but under-nourished – we’ve all heard the term ‘empty calories’ – filling up with calorie dense foods (added fat, sugar, and salt) rather than nutrient dense foods (full of vitamins, minerals, phytonutrients, and antioxidants). Dietary and lifestyle choices can directly contribute to the health of the brain and to psychiatric issues. Deficiencies of vitamins and minerals may contribute to mental illness and exacerbate symptoms, as well as compromise recovery. Deficiencies or insufficiencies of certain vitamins and minerals can cause poor concentration and memory (B vitamins, zinc, iodine), low mood and irritability (B vitamins, magnesium), and feelings of anxiety and depression (folate, selenium, vitamin C, magnesium, zinc, iron, vitamin D).

Vitamins and minerals contribute to several functions in the body, including helping your brain utilise fats, and building your neurotransmitters. They also help make energy from carbohydrates.

Key Vitamins Associated with Mental Health:

· B1 (thiamine): The brain uses B1 to help convert glucose into fuel, and without it the brain rapidly runs out of energy, contributing to fatigue, depression, irritability, memory problems, and anxiety.

· B2 (riboflavin): B2 is essential for mitochondrial function – creating energy in cells which is needed to perform all functions. Low levels are associated with many neurological complaints.

· B3 (niacin): Low levels can cause agitation and anxiety and lowered cognitive function.

· B5 (pantothenic acid): Low levels can cause depression, insomnia, and fatigue.

· B6 (pyridoxine): B6 is essential for conversion of amino acids into neurotransmitters like serotonin, melatonin, and dopamine.

· B9 (folate): Low levels are associated with depression.

· B12 (cobalamin): B2 deficiencies can cause pernicious anaemia, which can cause mood swings, paranoia, irritability, confusion, dementia, hallucinations, or mania, along with many physical symptoms.

You can see the whole spectrum of b vitamins are implicated in brain health. Dietary sources to provide these include meat, fish, poultry, beans and peas, lentils, nuts, dairy, eggs, mushrooms, green leafy vegetables, legumes, bananas and other fruits, potatoes, whole grains, and brassica vegetables. If you are vegan or vegetarian, special care is needed to ensure you supplement with certain B vitamins (especially B12) to ensure sufficient levels are maintained.

  • Vitamin C (ascorbic acid): Low levels of vitamin C play a role in depression.

    • Sources include citrus fruits, brassica vegetables, green leafy vegetables, squash, tomatoes and tomato juice, and potatoes.

  • Vitamin D (cholecalciferol): Low levels of vitamin D are associated with depression.

    • Sources include fatty fish and fish liver oils, sun-dried mushrooms, eggs.

Key Minerals:

  • Magnesium: Deficiencies are linked with apathy, depression, agitation, confusion, anxiety, and delirium.

    • Sources include dark green leafy vegetables, legumes, nuts and seeds, whole grains.

  • Calcium: Low levels have been associated with depression in middle-aged women.

    • Sources include dairy, fatty fish, green leafy vegetables, soya beans, tofu, nuts.

  • Selenium: Essential for a healthy thyroid, low levels are associated with depression.

    • Sources include seafood, meat, poultry, eggs, dairy, brazil nuts.

  • Iron: Iron deficiency has been linked to depression.

    • Sources include meat and poultry, seafood, tofu, green leafy vegetables, beans, broccoli, tomatoes, nuts and seeds.

Eat the rainbow

Nutrition is often overlooked as an essential component of good mental health. A study from 2014 found that vegetable consumption was correlated with high levels of mental well-being. Try and eat your 5-10 portions of fruit and vegetables every day (emphasising veggies over fruits). A portion is roughly equivalent to the size of your palm or fist. Aim to get as many colours into your diet as possible as each colour of the rainbow has a different health benefit.

Should I take a multivitamin?

A nutritional therapist can help determine whether or not you are at risk for insufficiencies or deficiencies, either by analysing your diet and the effectiveness of your digestion and absorption, or by conducting functional medicine tests, and deciding the best way to correct any dietary needs. It is not recommended to self-prescribe multivitamins as they vary significantly in quality, and you may be wasting your money and causing yourself harm.

There are two types of vitamins – water soluble and fat soluble. With water soluble vitamins your body eliminates what it does not need. However, with fat soluble vitamins (vitamins A, D, E, K), excess amounts accumulate over long periods of time as the body can’t easily get rid of them. In particular, vitamins A and D can have toxic effects in excess quantities. Although vitamin D toxicity is extremely rare, vitamin A can be particularly harmful to some people, especially pregnant women and smokers. If you take a high potency multivitamin and eat a healthy balanced diet, you can exceed the recommended intake of many nutrients. Lastly, a multivitamin is not a quick fix for a poor diet. It is important for long-term good health to eat a balanced diet of fresh, whole foods with plenty of fruits and vegetables.

Thanks to modern science we can test your individual levels of vitamins and minerals and tailor your diet based on your actual requirements. Contact us today to enquire about personalised nutrition based on these accurate scientific measurements.


How can we help?

There is growing evidence that the foods we eat and the balance of our gut microbiome can contribute to the state of our mental health. Poor diets or compromised digestion have been linked to various mental health issues including depression, schizophrenia, dementia, and ADHD. Of course, there are many other contributory factors which lead to mental health status, but eating a balanced, nutritious diet in combination with a healthy lifestyle can be an effective way to prevent or reduce mental health issues.

We will assess not only your diet but your health history, stress levels, medications, lifestyle and environmental stressors, family health, and other factors to get an understanding of your current health situations. In some situations, functional testing may be used to get a clear understanding of your micronutrient (vitamins and minerals) status, the state of your microbiome, your hormonal balance, and more. From this, together we build a fully comprehensive programme that fits in with your lifestyle and health needs.

Written by: Alissa Powell


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