by Laurel LeConte, Registered Dietitian
Most people are aware of the association between a nutritious diet and their physical health. However, there appears to be less emphasis on the clearly established relationship between diet and mental health, or “food and mood.” Although mental health is highly complex and influenced by many factors, in light of Bell Let’s Talk Day, I would like touch on how food affects mood and review a few recommendations to promote mental health through diet during a time of year when a disproportionate number of people report feeling blue.
There is a direct association between what we eat and how we feel. Consider for a moment how you felt the last time you drank alcohol, coffee or ate a piece of chocolate. Most people can relate to the short-term impact of food and mood. However, did you know that some foods can have a long-lasting impact on general mood and well-being due to the impact they hold on the structure and function of the brain?
How the brain works
The brain is partly composed of billions of nerve cells called neurons. Neuron allows the brain to communicate with itself. The neurons and associated structures are made primarily of fats or “lipids” derived from our diet. Specifically, the types of fat we eat can influence the brain’s flexibility to communicate as intended. Neurotransmitters are messages that pass back and forth between components of our brains. These neurotransmitters are made from amino acids which are often obtained directly through our diets. These neurotransmitters directly influence our moods and feelings. For example; the neurotransmitter serotonin is involved in releasing feelings of contentment whereas the neurotransmitters adrenaline and dopamine help us feel motivated.
Depression is a common mood disorder with many Canadians experiencing seasonal affective disorder. Seasonal affective disorder is defined as the onset of depression that occurs during the winter months when there is less natural sunlight. Several studies have examined relationships among different nutrients and depression. Low intakes of Omega 3 fatty acids, fruit and vegetables and high consumption of refined sugars and processed foods have been shown to increase the risk of depression.
In recent decades, an increased incidence in mental health conditions such as depression may be linked to changes in our diet observed over the same time frame. Changing nutrient profiles of our food supply also support this hypothesis. The “dry weights” of our brains are made up of about 60 percent fat, and the fats we eat directly affect the structure and function of brain cell membranes. Saturated fats, like those found in fatty cuts of meat, are expected to make the cell membranes in our brain and body tissues less flexible, whereas the Omega 3 and Omega 6 fats found in fatty fish and certain plant foods contribute to healthier brain tissue. Twenty percent of our brain fat is made from the Omega 3 and Omega 6 fats we get in our diet. Both are found in equal amounts in the brain and it is believed they should be consumed in equal amounts for maximum health benefit. However, changing dietary patterns and food production processes suggest that we are eating excessive Omega 6 fat relative to Omega 3 fat intake, leading to deleterious health effects. Healthy brain function involves balanced neurotransmitters. Our dietary patterns can make the brain less sensitive to its own regulation leading to negative feelings and mood. For example, correlations between decreasing intakes of fish by country and increasing levels of depression among its citizens and the reverse have been shown for many types of depression.
Foods that nourish the brain help the brain release and efficiently balance neurotransmitters and won’t lead to down regulation of neurotransmitter function. In general, added sugars, deep fried foods, excessive caffeine, alcohol and cigarettes can contribute to deficiency of neurotransmitters and are associated with mood dysregulation. Whereas antioxidants from nuts, seeds, fish, pulses, vegetables and fruits help the brain protect itself by allowing regulation of neurotransmitters associated with stable mood. Nutrients from food almost always demonstrate superior impact than those from dietary supplements.
Increased rates of mental health conditions such as depression are complex and are associated with biological, social and economic factors. Although changes in food consumption may be only a contributing factor, it may be one we can most easily influence.
Key points for improving mood with food
Carbohydrates are the brain’s primary and preferred fuel source. Choosing complex carbohydrates such as whole grains including rolled oats, wild rice, whole wheat and brown rice release glucose slowly during digestion. Slow digestion means your brain receives a more stable flow of fuel on which to function. Many of these whole grains also contain higher levels of nutrients than their more processed counterparts.
Emphasize essential fatty acids that your brain must obtain from your diet to function. These include Omega 3-rich oily fish like salmon, trout and sardines. Try to avoid deep frying your fish, which will change the beneficial nutrient profile it naturally contains.
Aside from nutrients and how they directly affect the brain, there are psychosocial effects of food. Consider how we feel eating alone versus sharing a meal among those that we love. Eat with others whenever possible.
Nutrition is an evolving science. We don’t know everything yet. Protect your health and maximize your nutrient intake by consuming the widest variety of plant food possible.
Omega 6 fats are still important for health, however we should minimize our intake of processed foods such as vegetable oils and deep fried foods which may contribute to the undesirable high intake of Omega 6 fat versus Omega 3. Consuming plant fats in their natural forms such as avocados, nuts, seeds and whole grains is anticipated to offer greater benefit than vegetable oils.
Water makes up about 80 percent of the brain and is an essential element in its functioning. Stay hydrated with water being the brain’s beverage of choice.
Studies have shown a link between vitamin D deficiency and depression. Anyone living in Canada cannot produce Vitamin D through sun exposure in winter months. Although vitamin D is stored in our body fat, it is recommended to take a supplement of 400 international units per day in winter months to ensure adequate vitamin D levels.
As previously stated, mental health conditions are complex with a myriad of factors at interplay. Food and overall lifestyle remain a pillar in factors that contribute to protecting mental health. Consider investing time and resources into planning the healthiest diet you can enjoy and maintain for year-round benefit.