The Mediterranean diet has an impressive global reputation. Not only is it good for our overall physical health but studies have also shown that it is a powerhouse eating-pattern that can help you manage clinical depression.
As good as the Mediterranean diet is, it’s not the only diet that can improve your mental health.
Professor Felice Jacka, director of the Food and Mood Centre led by Deakin University, explains that other international diets boasting similar principles to the Mediterranean-style diet can be just as effective in treating or preventing depression.
"What we put in our mouth is of relevance, not just to our physical health but to our mental health and brain health," says Prof Jacka, who is also the president of the International Society for Nutritional Psychiatry Research.
“But I don’t think there is anything so special about the Mediterranean diet because we know that traditional diets all across the world are associated with a reduced risk of depression.
“If you think about traditional diets in Norway for example, it is also rich in sulphurous vegetables, whole grains and fish.
“I don’t think there is anything so special about the Mediterranean diet because we know that traditional diets all across the world are associated with a reduced risk of depression.”
“If you think about traditional diets in Japan, they are high in vegetables, fermented foods, soy protein and fish.”
The Japanese dietary guidelines, also known as the 'Japanese food guide spinning top', have been identified as a possible reason why Japanese women have the longest life expectancies in the world.
The principles of this famed diet include the consumption of whole grains, fish, fruit, milk and beans; the avoidance of too much salt and fat; enjoying your meal; tracking what you eat and eating well-balanced meals regularly.
“Now think about traditional diets in the Mediterranean or even the UK, Australia and America. They are traditionally high in whole foods and low in processed or junk foods that are devoid of nutrients and high in added fats, salts, artificial sugars and emulsifiers.
“Foods that are grown and produced on a farm, which are not interfered with, are what we should be aiming to eat. Foods that are [highly] processed are not the foods to consume to maximise our physical mental health – generally, the processing process takes the out the good things and adds in bad things.”
Although Prof Jacka references ‘traditional’ foods, Australia’s current dietary guidelines also recommend that we consume a diet that is “high in whole foods is a diet that is high in vegetables, fruits, nuts, seeds, legumes, fish, whole grains, non-processed meats and olive oil”.
However, she stresses, Australians must understand that “whole grains means ‘whole grains’ – like barley, brown rice and quinoa – and not just brown bread”.
“Foods that are grown and produced on a farm, which are not interfered with, are what we should be aiming to eat."
But ‘why’ are these foods and diets linked to improvements in depression?
Prof Jacka explains that whole foods are preferable over highly processed foods because of highly processed foods may cause inflammation in our whole body and influence our gut. She says both of these dietary outcomes are linked to depression.
“Our gut’s resident microbiota drives inflammation in our body, which can influence metabolism, glucose regulation, body weight and the health of our brain.
“And the most important factor affecting our gut is our diet. You can change your gut microbiome within hours of changing your diet.”
A review on the gut microbiome from 2015 found that our gut microbiota plays a role in maintaining an intestinal barrier function. It shows that the disruption of this function can affect our central nervous system and lead to stress-related psychiatric disorders.
Another smaller review on the gut-brain axis, published in 2017, highlights the importance of a healthy microbiome, especially the gut microbiota, for people living with anxiety and depression. It also links an imbalance in the gut microbiota and inflammation in the central nervous system to potential causes of mental illness.
“So if you adopt a diet that is gut-friendly – one that is high in plant fibre, fruits, vegetables, polyphenols and healthy fats, then you avoid the things that we know that damage the gut – artificial sugars and emulsifiers,” says Prof Jacka.
“And if we adopt a diet that is gut-friendly this will positively benefit almost every aspect of our body and brain.”
However, stresses Prof Jacka, a healthy diet should never replace other forms of medical treatment and must always go hand-in-hand with therapy and medication, as recommended by a mental health or medical expert.
"Diet is not the only thing that will cause or treat depression. We are not in any way suggesting that people adopt a healthy diet instead of following other forms of treatment.
"Having a healthy diet is something you do, with exercise, [to create a good] foundation for your mental health."