We have all heard it. Eat better, feel better. But what’s the connection between what we eat and how we feel?
Evidence for a link between what we eat and how we feel is fairly new. The first studies to be published on this were as recent as 2009. This new area is called “nutritional psychiatry.” The relationships between foods and mental health are complex, and we’re just starting to understand them.
What foods are associated with worse moods? These not-so-healthy dietary patterns include higher intakes of:
● Saturated fat and processed meats
● Refined sugars and starches
● Fried and processed foods
People who eat this way tend to report more mental health symptoms than those who eat a more health-promoting diet. Several recent studies consider poor eating habits to be a risk factor for some mental health issues.
There is much talk today about inflammation and not surprisingly, these not-so-healthy foods are also linked with higher inflammatory markers. Several studies show that improving the diet can reduce levels inflammation and some studies show that the higher the “inflammatory factor” of the diet, the higher the risk for mental health issues.
One dietary pattern that’s been studied a lot is the Mediterranean diet. This diet includes a lot of vegetables, fruit, whole grains, legumes, fish, and olive oil. It also contains a lot of nutrients and fibre. Eating a Mediterranean-style diet is associated with lower levels of inflammatory markers and a reduced risk of mental health issues.
This complex association between food and mental health can go both ways. Mental health symptoms can also influence appetite and food choices, and it’s likely that other factors such as obesity, exercise, and use of alcohol and tobacco are probably involved as well.
We don’t know exactly how these eating patterns affect mental health - inflammation is definitely one possibility. Nutrition can impact how our immune system functions, and this can affect levels of inflammation, and mental health issues. It could also be through the effects of the nutrients themselves, and even directly through the digestive system (microbiota-gut-brain axis).
A recent clinical study, the SMILES trial, found that when people start eating a healthier diet, they can actually reduce some of their mental health symptoms. What makes the results from the SMILES trial strong is that it was an actual experiment. It didn’t just ask people what they ate, measured their inflammatory markers, and what their symptoms were. It was “interventional” - people agreed to actually change the way they ate.
The researchers say “...this is the first randomized control trial to explicitly seek to answer the question: If I improve my diet, will my mental health improve?”
The SMILES trial recruited 67 people with depression and poor dietary quality for a 12-week trial. These were people who reported a high intake of sweets, processed meats, and salty snacks; and a low intake of vegetables, fruits, lean protein, and dietary fibre.
Half of them were asked to:
1. Eat more vegetables, whole grains, fruit, legumes, low-fat unsweetened dairy, raw and unsalted nuts, fish, lean red meat, chicken, eggs and olive oil; and
2. Eat less sweets, refined grains, fried food, fast food, processed meats and sugary drinks; and,
3. Drink no more than 2 glasses of wine per day (with meals, preferably red wine).
This group was also given seven professional nutritional counselling sessions.
The other group was given social support. They were “befriended” and discussed sports or news, or played cards or board games. There was no nutritional support, nor any dietary recommendations offered.
The researchers found that in 12-weeks the people who improved their diet actually also improved some mental health symptoms! They said “We report significant reductions in depression symptoms as a result of this intervention…the results of this trial suggest that improving one’s diet according to current recommendations targeting depression may be a useful and accessible strategy for addressing depression in both the general population and in clinical settings.”
Although this was a small trial, the results are not surprising, as the body requires essential nutrients to function at its best. In time, no doubt, similar larger trials will continue to support these results. In the meantime, eating a more health-promoting diet is helpful for so many conditions, not just mental health conditions.
By now you might be asking if there is something special in these foods that may help with moods? Indeed there is. Essential nutrients. We know the brain needs enough of all essential nutrients in order to function properly, and insufficient levels are linked with stress and a compromised immune system. Eating nutrient-dense foods is the best way to get complete nutrition.
Here are a few key nutrients to support better moods.
B-vitamins such as B6, B9 (folic acid), and B12
People who tend to be low in B-vitamins are more likely to have mental health issues. Higher intakes of vitamin B6 (pyridoxine) and B12 (cobalamin) may reduce risk. With folic acid in particular, the connection may be due to its different forms. Folic acid is the inactive form of vitamin B9 and our bodies naturally converted it into the active form. Once folic acid has been activated, it goes to the brain and is used to make key neurotransmitters that keep our brain functioning efficiently. An ideal way to take in enough B9 is to consume folate-rich foods such as avocado, beetroot, spinach, asparagus, and Brussels sprouts.
One of the well-known roles of vitamin D is to help absorb calcium for strong bones, but it has a number of other roles. It plays a part in circadian rhythms and sleep, and influences the growth of nerve cells in the developing brain. There is growing evidence that people who tend to be low in vitamin D also tend to have more mental health symptoms, and some studies show that vitamin D supplementation can improve mood and reduce mental health symptoms. Vitamin D is the most commonly deficient nutrient in Western countries. It’s known as the “sunshine vitamin” because our skin makes it when exposed to sunlight. It is also found in a few foods such as salmon, sardines, mackerel, cod liver oil, mushrooms, and egg yolks.
Minerals (Calcium & Selenium)
Low intake of calcium is associated with mental health symptoms, while high intake is associated with lower rates of mental health symptoms. Food sources of calcium include broccoli, kale, okra, sardines and salmon (with bones), and raw almonds and sesame seeds.
Depression has been associated with low blood levels of the essential mineral selenium. Low intake of selenium is also associated with an increased risk for depression. Selenium is present in Brazil nuts, eggs, halibut, sardines, and spinach.
Omega-3 oils are healthy fats found in many foods such as seafood, nuts, legumes, and leafy greens. They have been shown to reduce inflammation. Some (but not all) studies suggest that the omega-3 fats, specifically those found in fish and fish oil, have mental health benefits.
In conclusion, evidence is showing that what we eat has a direct bearing on how we feel. By following a healthy diet and modifying our lifestyle choices, we can improve our overall health.
This is Janice, inspiring change.
References: https://bmcmedicine.biomedcentral.com/articles/10.1186/1741-7015-11-200; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5372937/; https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-017-0791-y; https://bmcpsychiatry.biomedcentral.com/articles/10.1186/s12888-016-0900-z