Rather than reaching for comfort junk foods when we’re feeling down, we should fuel our bodies with mood-protective foods.

In a world first, an Australian research team has discovered a wholesome, healthy diet can lessen depression.

In the SMILES trial, published in the journal BMC Medicine, researchers at Deakin University’s Centre for Innovation in Mental and Physical Health and Clinical Treatment randomly assigned adults with major depressive disorder into three months of either dietary or social support.

Those getting the dietary treatment experienced a much greater remission of their symptoms: a third of them met criteria for remission, compared with 8 per cent of participants in the social support group. Those sticking most closely to the diet recommendations gained the most improvements.

In a 2017 media release, Felice Jacka, director of Deakin’s Food and Mood Centre, said: “While approximately half of sufferers [of depression] are helped by currently available medical and psychological therapies, new treatment options for depression are urgently needed.”

So what did they eat?

Those in the dietary group were merely instructed to eat more vegetables, fruits, wholegrain, legumes, lean meats, fish, olive oil and nuts and less of the naughties: sweets, refined cereals, fried and fast food, processed meat and sugary drinks.

Sydney-based nutritionist, speaker, author and founder of A Healthy View, Michele Chevalley Hedge, explains that when we eat a balanced diet of wholefoods, our bodies, brains and hormones simply work better.

The mental-health hijackers

Certain foods, like sugar, excess sodium, caffeine and food allergens, can act as mental-health hijackers that destabilise our body chemistry, blood sugar and mood.

“When people are super-sugar high, they get equally as low,” Ms Chevalley Hedge says.

Too much caffeine can destabilise our body chemistry, blood sugar and mood. Photo: Getty

Heavy amounts of dietary sugar can be related to brain fog, ADHD type symptoms, anxiety and depression, and disrupt the hormone insulin, in turn wreaking havoc on concentration, memory, and sleep.

Recent research also links excessive dietary sugar to Type-3 diabetes, a condition involving the vascular network of the brain and linked to Alzheimers, Ms Chevalley Hedge says.

Not everything that looks like mental health is

Harvard psychiatrist and author of Masquerading Symptoms (2014), Barbara Schildkrout, found up to 25 per cent of mental health issues are caused by physical medical complaints, including nutritional deficiencies and thyroid and blood-sugar issues. Lack of understanding such factors in mental health can lead to potential for misdiagnosis and ineffective treatment.

Ms Chevalley Hedge says things that appear like mental health problems can be driven by dietary issues.

“When someone has a sluggish thyroid, hyper or hypo, these people feel anxiety or depression, they feel lack of energy, and are often put on an antidepressant. The thyroid needs to be nourished with foods rich in iodine and selenium.”

Deficiencies in both those minerals are common in Australia.

Low levels of B12 and iron are linked to anxiety and depression. Vegans and vegetarians are particularly susceptible.

“Iron and B12 affect neural transmitters like dopamine and serotonin,” Ms Chevalley Hedge explains. “These are the very things that make us happy.”

Unhealthy fats, alcohol and junk foods can negatively impact the liver, leading to a greater risk of hormone-related, premenstrual moods in women. The liver plays a vital role in detoxification, including ridding our body of excess hormones like oestrogen, Ms Chevalley Hedge explains.

Mood starts in the gut

Scientists have discovered about 80 to 90 per cent of the feel-good hormone, serotonin, is created in our guts, Ms Chevalley Hedge says.

Excess sugar and bad diets can create havoc in our guts contributing to IBS (irritable bowel syndrome) and candida overload, negatively impacting serotonin production. 

The fatty acids found in many fish can aid cognitive function. Photo: Getty

Essential nutrients

Ms Chevalley Hedge adds that key nutrients for mental health are fatty acids EPA and DHA (rich in fish and known to enhance cognitive function), B12, iron, iodine, selenium and vitamin D.

Deficiencies in vitamin D (the sun is our major source) have been linked to seasonal affective disorder.

A balanced approach

However, the emphasis should be on a balanced, unprocessed wholefood diet, low in sugar, high in fibre and antioxidants.

“Get rid of trans-fats, hidden sugars. We have a lot of really healthy looking things on the market full of sugar.  Even honey yoghurt contains six to seven teaspoons of sugar.”

“Mental disorders like depression and anxiety are multi-factorial. It’s about going back to the basics – like sunshine, real whole food, exercise, sleep. These should underpin everybody’s mental health.”