NUTRITION
Learn about the link between food and mental health
With so much emphasis put on how the food we eat affects a person’s physique and energy level, it’s important not to lose sight of how it can also affect one’s state of mind. Here, we explore the link between food and mental health, and how the digestive process directly influences your mood.
The foods we eat actually become our brain cells. The brain is mostly made up of essential fatty acids, which we must get from our diet in the form of omega-3 and omega-6 fatty acids. Omega-3 is found primarily in fatty fish, while omega-6 is found primarily in vegetable oils.
Having lived through a global pandemic, it’s safe to say it’s been a tough year and a half for most Canadians. Anxiety, loneliness and social isolation, uncertainty, fear of the virus, online learning, job loss and financial stress as a result of lockdowns have all wreaked havoc on our mental health. A poll conducted by Mental Health Research Canada in June 2021 indicated that 24 percent of Canadians reported self-rated high levels of anxiety, and 16 percent reported self-rated high levels of depression, compared with 8 percent and 7 percent, respectively, before the COVID-19 outbreak.
While psychotherapy and medication are the primary interventions for mental health conditions like anxiety and depression, what we eat can also have a major impact. In fact, diet is the number one modifiable lifestyle factor to help decrease the risk of depression. A meta-analysis of 11 studies containing a total of 101,950 participants showed that an unhealthy diet can actually increase the likelihood of developing depression by 40 percent. Unfortunately, diet is not often discussed as a tool in the treatment and prevention of mental illness, mood disorders or cognitive decline. Increasingly, though, science is uncovering the link between diet and mental health, and providing evidence to support the use of dietary interventions. As a result, nutritional psychiatry is an emerging area of research that looks specifically at the role of nutrition in the development and treatment of mental illness.
The landmark 2017 SMILES Trial was a randomized controlled trial (the gold standard of scientific research) that looked at people with major depression. During the 12-week study, participants were randomly placed into two groups, and received either social support or nutrition counselling to follow a Mediterranean-style diet. The Mediterranean diet is high in vegetables, fruits, whole grains, legumes (lentils, beans, peas), nuts, sources of healthy fats including olive oil, fish and seafood, includes small amounts of poultry, meat and cheese, and is low in sugar and processed foods like pop, baked goods, fast food, deli meats, processed snacks and the like.
Depression scores were taken down at both the beginning and the end of the 12-week intervention. Both groups saw improvement in their symptoms, but the group that received nutrition counselling had significant improvement in their symptoms and, in fact, in 25 percent of the participants, symptoms were lessened to the point that they were no longer classified as severely depressed. This was the first study to show evidence that diet has a significant impact on symptoms of depression.
The 2019 HELFIMED Study found similar results. In this study, half the participants followed the Mediterranean diet and took a daily omega-3 supplement, while the rest participated in a social support group. At the end of three months, both groups saw improvement in their depression scores, but the diet group had substantially greater improvements in symptoms, so much so that the average depression score in this group no longer met the criteria for extremely severe. Plus, these improvements to the participants’ symptoms were sustained three months after the intervention period ended.
How does what we eat affect our brain?
The composition, structure and optimal functioning of the brain are all dependent on the proper nutrients being available in the body. To start, the foods we eat actually become our brain cells. The brain is mostly made up of essential fatty acids, which we must get from our diet in the form of omega-3 and omega-6 fatty acids. Omega-3 is found primarily in fatty fish, while omega-6 is found primarily in vegetable oils. The typical North American diet—which includes plenty of processed foods containing high levels of vegetable oils—has more than enough omega-6, but is often deficient in omega-3, resulting in an unbalanced ratio of these two essential fatty acids. The problem is that omega-6 has proinflammatory properties, while omega-3 has antiinflammatory properties. For this reason, getting enough omega-3 and limiting highly processed foods is essential for the health of the brain.