Wednesday 10 October marked World Mental Health Day. This year’s theme ‘Do You See What I See?’ challenges perceptions about mental illness in Australia and encourages everyone to look at mental health in a more positive light, in an effort to reduce stigma and make way for more people to seek help.

The relationship between food and mood is an important and increasingly informative aspect of current mental health studies. In his recent presentation as part of the St Catherine’s Girls Talk Seminar Series, clinical psychologist Andrew Fuller remarked that ‘What we eat changes our moods’.

Felice Jacka, Professor of Nutritional Psychiatry at Deakin University, Director of the Food and Mood Centre and Founder and President of the International Society for Nutritional Psychiatry Research, has collected fascinating data that shows the significant correlation between poor diet and poor mental health, including the incidence of depression.

‘Professor Jacka has pioneered a research program that examines how individuals’ diets, and other lifestyle behaviours, interact with the risk for mental health problems. This research is being carried out with the ultimate goal of developing an evidence-based public health message for the primary prevention of the common mental disorders.’[1]

Since 2009, the Food and Mood Centre team have led many observational studies showing that ‘diet matters to depression’. These studies concluded that ‘those with better quality diets were less likely to be depressed, whereas a higher intake of processed and unhealthy foods was associated with increased anxiety’. Links to Jacka’s journal papers can be found on the Centre’s website.

Jacka acknowledges that mental illness can promote a change in diet rather than the other way around. However, the research, including the benefits of adopting a Mediterranean-style diet, showed that, even with their small sample size, they were able to show a strong trend for the prevention of new cases of depression for those adopting a Mediterranean-style diet.

The Food and Mood Centre notes that, ‘It is important to understand that researchers now believe that depression, in particular, is not just a brain disorder, but rather a whole-body disorder, with dysfunction of the immune system as an important risk factor. Chronic, low-grade systemic inflammation can be a result of environmental stressors such as poor diet, lack of exercise, smoking, overweight and obesity, lack of sleep, lack of vitamin D, as well as stress.’ The Centre explains that ‘gut microbiota seem to be critical to almost every aspect of health including metabolism, body weight, brain function and health. Each of these factors is highly relevant to depression, reinforcing the idea of depression as a whole body disorder.’

Jacka explains, ‘A diet high in saturated fats and refined sugars has a very potent negative impact on brain proteins that we know are important in depression: proteins called neurotrophins, which protect the brain against oxidative stress and promote the growth of new brain cells.’ Jacka references an important study which showed ‘a clear relationship between the quality of older adults’ diets and the size of their hippocampus, a section of the brain that is central to learning, memory and mental health and that relies on neurotrophins to grow new cells.’

With the increasing incidence of anxiety and depression in contemporary society, the need for establishing protective factors has never been so important. The onset of mental illness is typically around mid-to-late adolescence so it is particularly important that parents are aware of the new research drawing a link between diet and mental health.

The Food and Mood Centre team note that ‘the 20th century has seen major shifts in dietary intakes globally, with a marked increase in the consumption of sugars, snack foods, take-away foods and high-energy foods. At the same time, the consumption of nutrient and fibre-dense foods is diminishing. These changes are particularly obvious in younger cohorts.’

Of concern is the fact that studies have shown that young people are not meeting many health-promoting recommendations, particularly when it comes to eating a healthy diet. In Australia, ‘fewer than five per cent of adolescents eat the recommended amount of fruits and vegetables and they are much more likely to be regularly eating nutrient poor, high sugar foods’. The scientific research shows that what children and adolescents are eating is critically important to their brains and mental health as well.

The good news, however, is that these studies suggest that a good quality, healthy diet – high in fruits and vegetables – can be protective of mental health. The Food and Mood Centre recommends a diet mainly constituted of plant foods such as vegetables, salads, fruits, legumes, wholegrains, raw nuts, fish, lean red meats and healthy fats such as olive oil.

In his ‘Depression Proofing Your Kids’ online resource, Andrew Fuller states that countries that eat low levels of fish have higher levels of depression. Fish contains a fatty acid known as EPA, which is lacking in those with depression. Leafy greens have magnesium in them which helps with depression and with sleep patterns.[2]

The term ‘food for thought’ is certainly taking on a new meaning as research and data present the correlation between diet and mental health.