Conventional wisdom tells us we are what we eat, and a lack of nutrients has been shown to contribute to poor mental health in those with anxiety and depression, but food as a powerful antidepressant is yet to be widely accepted by mainstream medicine.

At present, cognitive behavioural therapies and pharmacology are the traditional treatments of choice. However, while health professionals are far from referring patients with mental health complaints to dieticians for treatment, it is an exciting time to be involved in nutritional psychiatry.

What is nutritional psychiatry?

Nutritional psychiatry is a relatively new field of study that focuses on food and supplements as an alternative treatment for mental health conditions. Research is still in its infancy, but developments are emerging that show a link between nutrition and remission in depression and anxiety.

What we eat plays an enormous role in supporting or negatively impacting our mental wellbeing according to Dietitian Kara Landau of Uplift Food.

“Diet is essential to preventing inflammation, which has been shown to be connected with anxiety and depression and to ensure adequate vitamins and minerals are present for hormone regulation.

“Our diet, and in particular, a gut-healthy diet, plays an integral role in managing our mood. Our gut and our brain are directly connected, and with 90 per cent of our mood-calming serotonin found within our gut, it is clear that how we nourish our gut can play a profound role in preventing anxiety and depression,” said Ms Landau.

In treating a patient with depressive symptoms, Ms Landau recommends an anti-inflammatory and gut-friendly diet, including prebiotics and probiotics, dietary fibre, omega 3’s, and Vitamin D. The inclusion of Vitamin B and magnesium are also important as they are known to play a part in the serotonin pathway.

“I would strongly recommend a gut-healthy diet made up of prebiotic rich ingredients, and this would include foods that contain prebiotic fibres and resistant starches, as well as polyphenolic compounds.

“Prebiotic rich ingredients include Jerusalem artichokes, asparagus, onions, green bananas (can be found in a flour form), roasted and then cooled potatoes, raw oats (i.e. overnight oats).

“I also recommend probiotic-rich foods and beverages such as kefir and skyr.

“Foods rich in healthy fats such as omega-3 rich salmon and algae-based products, monounsaturated foods such as avocados and extra virgin olive oil, Vitamin B6-rich foods such as pistachios, and Vitamin D, ideally attained from sunshine, but otherwise foods such as salmon, eggs (in the yolk) and even high vitamin D mushrooms.”

It is just as important to remove certain foods, said Ms Landau, as high glycaemic index and refined carbohydrate-rich foods are known to cause inflammation in the body. 

Lifestyle factors, such as being active, minimising stress and having a supportive social network, are also crucial in the treatment of depression and anxiety, according to Ms Landau. 

“I would advise social and lifestyle orientated supportive environments, including finding people and activities that create calming environments. Being active and outdoors can often assist people, alongside the other dietary and lifestyle recommendations,” said Ms Landau.

Nutritional psychiatry and research

A 2017 SMILES (Supporting the Modification of lifestyle in Lowered Emotional States) trial by the Food and Mood Centre showed that in a group of people who had dietary support, one third met criteria for remission of major depression, compared to only eight per cent of those in a social support group.

Sports Dietitian Aidan Muir of Fuel Your Life says the study, which was based on a modified Mediterranean diet, is a considerable achievement toward progressing awareness of nutritional psychiatry.

“The theory as to why it was so effective is because the diet has an anti-inflammatory effect that may reduce inflammation in the brain which could be an influencing factor in depression and anxiety.

Dietitian Emily Hardman says research also suggests eating a diet high in processed foods with added fat, sugar and salt, can increase and exacerbate symptoms of anxiety and depression.

“When you are feeling tired, anxious or stressed, your emotional hunger signals can push you to choose these ‘comfort' foods. However, rather than making you feel better, these foods often leave you feeling physically and mentally worse.”

Dietary advice for optimal mental health.

The quality of one’s diet is directly related to their risk of depressive symptoms according to Ms Hardman, who said many dietary strategies could assist in managing mood, feelings and energy levels.

Eat regularly
Eat regularly and choose foods that are slowly digested by the body to help stabilise blood sugar and energy levels. Eating infrequently will lead to tiredness, irritability, and choosing foods that will spike your energy levels (which are not the best choice).

Aim to eat every three to four hours and include a sustaining carbohydrate, such as whole grain bread and cereal, rolled oats, fruit and vegetables, with your meal or snack.

Love your fruit and veg
Fruit and vegetables contain a variety of vitamins, minerals, antioxidants and fibre. Aim to have two serves of fruit and five serves of vegetables every day. The more colour and variety, the better it will be for your health.

Healthy fats
The brain relies on healthy omega-3 and omega-6 fats to function optimally. Include a variety of healthy fats such as extra virgin olive oil, nuts and seeds, and oily fish in your diet every day.

Look after your gut
The gut microbiota is a community of bacteria that live in your gut. A healthy gut is linked to a healthy mind. The bacteria in your gut feed on the food you eat, therefore the food you eat influences the health of your gut microbiota. A balanced diet that promotes good gut health has been associated with lower rates of mental illness including depression and anxiety.

• Choose fibre-rich foods such as fruit and vegetables, nuts and seeds, beans and legumes, and whole grains.
• Include fermented foods such as yoghurt, kefir and sauerkraut.
• Drink enough water.
• Limit intake of refined and processed foods as these can have a negative impact on gut health.

Stay hydrated
Adequate water is essential for the mind to help you to think, concentrate and focus. It also helps to keep your digestive system healthy and functioning optimally. Aim for six to eight glasses of water every day.

Moderate coffee
Caffeine is a stimulant which means it will give you a quick burst of energy. However, energy levels often drop off soon after. Overconsumption of caffeine can leave you feeling anxious, depressed, irritable and unable to sleep. Aim for no more than two coffees per day (ideally in the morning).

Nutritional psychiatry as an adjunct treatment for mental health.

Nutrition's role in the prevention and treatment of depressive illness is not as strong as it needs to be, according to Ms Landau. "I hope that in the coming years, as the discussion gains more attention, practitioners will begin to look at nutrition psychiatry as an adjunctive treatment to the range of other solutions currently being utilised with patients.”

Mr Muir agrees: “I think most health professionals considerably underrate the link between diet and mood. Most people understand that it is a factor, but very few understand how significant a role it plays.

“Making information available and encouraging GP's to refer to a dietitian as part of the treatment plan for depression and anxiety is a step in the right direction.”