Mediterranean Diet and Mental Health
Brain food carries a different meaning these days with an increasing evidence base showing that our diet can affect more than just our stamina and energy levels. It can also affect our cognitive function, memory and mental wellbeing. ‘Eating yourself happy’ is a buzz phrase of the times, nevertheless, it’s a motto worth living by.
The World Health Organisation defines mental health as “a state of well-being in which every individual realises his or her own potential, can cope with the normal stresses of life, can work productively and fruitfully, and is able to make a contribution to her or his community”1. The statistics on mental health issues among Australians are astounding. According to Beyond Blue, up to 45 per cent of people will experience a mental health condition in their lifetime2.
It’s timely that we explore this topic as the Australian government has established a Royal Commission into mental health. The task of the Royal Commission is to better understand the role of treatments, and to ensure that the health system is more adept at managing those suffering from poor mental health. One of the commission’s preliminary findings is that the system has “catastrophically failed to live up to expectations”. The report so far has also acknowledged that the mental health system in Australia is over-reliant on medication as a form of treatment3.
It is clear that in addition to drug therapy, treatment for mental health illnesses has included social support services, psychology/psychiatry, behavioural cognitive therapy, music and art therapy as well as meditation and mindfulness. However, new and exciting research is showing that our mental health can be strongly influenced by what we eat.
It’s important to recognise that it’s the overall quality of our diets that matters most, not single nutrients or foods. We need to see nutrition and our diets through a wider lens, and consider how a more diverse range of foods and nutrients can be included in our diet. Therefore, targeting dietary therapies that focus on the whole dietary pattern may assist in a person’s recovery from mental illness. This has been the focus of investigation in recent years.
But which diet is best?
Current research in nutrition science is showing that the adoption of the Mediterranean Diet can reduce depressive symptoms and enhance overall wellbeing in the long-term.
This diet has emerged from countries around the Mediterranean Sea – namely Greece, Italy and Spain. Research shows that the Mediterranean Diet may help to slash our risk of developing heart disease, lower blood cholesterol levels4 and blood pressure5, and improve glycaemic control for those with Type 2 Diabetes6.
The Mediterranean Diet largely consists of plenty of fresh fruit and vegetables, oily fish, legumes, nuts and seeds, whole grains and herbs and spices. Meanwhile, the predominant fat source in the diet is extra virgin olive oil (EVOO). Alcohol does feature in the diet, however, it is enjoyed in small amounts and usually with meals.
Extra Virgin Olive Oil
While we need to be careful not to isolate single foods in the diet, it is important to acknowledge the health benefits of EVOO. After all, it’s a key pillar of the Mediterranean Diet. Studies show that the consumption of 60ml a day (3 tablespoons) can have profound health implications – this dietary change alone can greatly reduce one’s risk of cardiovascular disease, metabolic syndrome and type 2 diabetes<sup7,8.
EVOO is a nutritional dynamo. It’s rich in a range of active compounds that have been demonstrated to provide numerous health benefits. In fact, these features, specific to olive oil, appear to contain free-radical scavenging properties to moderate oxidative damage. EVOO boasts a remarkable nutritional profile. In addition, it’s full of heart-healthy monounsaturated fats and antioxidants such as polyphenols and phytosterols, as well as vitamin E.
Further, the anti-inflammatory effects synonymous with EVOO may help to reduce the low-level grades of inflammation commonly associated with poor health9.
Food, mood and mental health
New research being conducted in Australia has clearly identified a ‘cause and effect’ relationship between our diet quality and our mental health10. This relationship was once seen to be an association rather than something that was more definitive. However, the SMILES trial (Supporting the Modification of Lifestyle in Lowered Emotional States) revealed that there is, in fact, a clear cause and effect relationship between our food intake and mental health11.
The SMILES trial is the first intervention study of its kind, and it has led to an understanding of the role of diet as a treatment strategy for depression. Participants in the intervention group were instructed to follow a modified Mediterranean Diet – a hybrid based on Australian and Greek dietary guidelines, with control group participants taking part in social support groups.
Research participants who ate a modified Mediterranean Diet reduced their depressive symptoms than those who were part of a social support group. These results were seen after only three months11.
Data from the PREDIMED study showed that eating a Mediterranean diet not only protected participants’ hearts, but also reduced the prevalence of depressive symptoms7. Research from this pioneering study also highlighted an unintended benefit for participants’ sleep. Nutrients commonly found in nuts and seeds, oily fish, lean meat (especially turkey) contribute good amounts of tryptophan, selenium, omega 3 fatty acids and vitamin D, which have all been shown to improve sleep 12. Inadequate sleep and/or poor sleeping patterns and mental health disturbances are common bedfellows13.
Further, emerging research is showing that a specific subclass of polyphenols, known as flavonoids have been associated with a decreased risk of depression14. Flavonoids are commonly found in EVOO, dark chocolate, berries, tea, herbs and red wine. These foods commonly feature in the Mediterranean Diet. A high intake of flavonoids is also showing promise in slowing cognitive decline in older adults15. Flavonoids direct mode of action in reducing depressive symptoms is unclear, however, they are a powerful class of antioxidants and therefore help to combat free radicals that cause oxidative stress.
The Mediterranean Diet and gut health
The link between our gut microbiome and overall health is an area of great interest in the scientific community. That’s because a poorly balanced microbiota has been linked to obesity, autoimmune disorders, asthma, allergies and diabetes16. Emerging evidence has shown how our gut microbes can affect our brain function. Links have been found between depression, anxiety and mood disorders with an out-of-kilter gut microbiota.
One recent study has shown that the adoption of a Mediterranean Diet leads to changes in the gut microbiome that can be linked to improvements in cognitive function and memory17. It is well established that the fibre-rich containing foods that commonly feature in the Mediterranean Diet such as fruit, vegetables, legumes, nuts and seeds and whole grains lead to gut microbe diversity in the colon. And it is this diversity of microbes that is believed to result in favourable outcomes in overall health, cognitive function and mental health18.
Moreover, new research in animal models has demonstrated how EVOO can help to positively influence the microbiota19. Undertaking research in humans to explore whether these same effects can be replicated should be a consideration for researchers.
Dietary improvement has been shown to be an effective strategy for the management and prevention of mental health disorders. Dietitians and nutrition professionals should be part of the multidisciplinary team to help treat patients with depressive symptoms and generalised anxiety disorders.
The role of diet is a significant piece of the complex mental health puzzle. And it is likely that dietary intervention will prove to play an important role in the future to ensure that successful outcomes are achieved.
Click here to view Joel’s brain healthy recipe for Yemista (stuffed vegetables).