There is a growing (excuse the pun) body of evidence that a healthy diet can prevent or ameliorate depression. My mother making me eat my vegetables, yes, even Brussels Sprouts was correct. We know they are good for us physically but also contribute to our mental and emotional wellbeing.

A diet high in fruits, vegetables, whole grains, fish and unprocessed lean red meat can prevent depression and once it has occurred can ameliorate its effects. And an unhealthy diet, high in processed and refined foods increases the risk in everyone, including children and teens.

A team of researchers, led by Deakin University epidemiologist, Felice Jacka, investigated whether changing the diets of people with serious depression would help improve their condition. Their small study of people with depression included groups already being treated with antidepressants, another treated with psychotherapy, and another treated with both.

Half of the people in the trial were given nutritional advice from a dietitian, assisting them to eat a healthier diet. Half were given one-to-one social support after being paired with someone with whom to converse and play cards. This type of social interaction is already known to assist people with depression.

The people who improved their diets showed significantly happier moods than those who received social support after three months. The people who improved their diets the most improved the most. This study was published in January 2017. A second, larger study led by researchers at the University of South Australia and published in December 2017 drew similar conclusions.

There are many causes of depression, including a genetic predisposition. It can be triggered by traumatic events or situations such as loneliness, or brought on by lifestyle choices. According to Drew Ramsey, a psychiatrist in New York, assistant clinical professor of psychiatry at Columbia University and author of<em> Eat Complete,</em> depression is about an unhealthy brain.

He explains that when we think of cardiac health, we think of strengthening the heart. We need to start thinking of strengthening another organ, the brain, when we think of mental health.

A bad diet can make depression worse, failing to provide the brain with the variety of nutrients it needs, Ramsey says. Inflammation of the brain, believed to be a cause of depression is exacerbated by trans fats which are high in processed or deep-fried foods. Ramsey has created an e-course called Eat to Beat Depression.

Lisa Mosconi, a neuroscientist, nutritionist and associate director of the Alzheimer’s Prevention Clinic at Weill Cornell Medical College in New York advises that a bad diet also affects the trillions of micro-organisms that live in our gut. They make molecules that can alter the production of serotonin, a neurotransmitter found in the brain.

So what should we eat for a healthy brain?

A Mediterranean-style diet made up primarily of fruits and vegetables, extra-virgin olive oil, cheese, legumes, nuts, seafood, whole grains and small portions of red meat will provide the nutrition our brain needs, says Mosconi, author of Brain Food: The Surprising Science of Eating for Cognitive Power.

A good diet should not replace other treatment for depression. But we should pay attention to the food we eat for physical and mental health reasons. So, Nanna and Mum are right, eat up those Brussels Sprouts!