What can the Arctic teach us about diet and mental health?

We often think of mental health as being influenced primarily by genetics, life experiences and our environment. But what if we have overlooked one of the most fundamental influences on the brain: what we eat?

While researching the links between diet and mental health, I came across a fascinating paper published in the International Journal of Circumpolar Health in 2003, with the title Diet and mental health in the Arctic: is diet an important risk factor for mental health in circumpolar peoples? The researchers explored an intriguing question: could changes in the traditional diet of Arctic populations be contributing to the deterioration in both physical and mental health seen with increasing Westernisation?

Traditional diets in circumpolar communities were shaped by an environment where growing food was difficult and the growing season was extremely short. Instead, people relied heavily on foods that could be hunted, fished or gathered. These included marine mammals, fish, wild ungulates such as caribou, fur-bearing animals such as bears and other wild animals, birds and eggs, alongside locally available plants and berries.

In other words, these were diets based predominantly on whole, nutrient-dense foods, with substantial amounts of protein and fat and relatively little carbohydrate. Many of these foods would also have provided important nutrients for brain health, including omega-3 fatty acids, minerals such as selenium, and a range of other micronutrients.

The authors point out that despite a diet relatively high in animal foods and fat, obesity, diabetes and cardiovascular disease were historically uncommon in many circumpolar populations. However, as traditional diets and lifestyles changed and Western processed foods became increasingly available, rates of metabolic disease began to rise. At the same time, mental health also deteriorated, with increasing rates of depression, anxiety, seasonal affective disorder and suicide being reported.

This is particularly interesting because the Arctic environment itself has often been proposed as a possible explanation for poor mental health. The extreme cold, long periods of darkness and limited sunlight certainly present significant challenges. Seasonal affective disorder, for example, is more common at higher latitudes.

But the researchers noticed something that didn't fit with this hypothesis. Some of the more isolated circumpolar populations, who had retained more of their traditional lifestyles and diets, did not appear to experience the same increase in mental health problems. This led the authors to suggest that diet may be an important, but under-recognised, risk factor for mental health. It is also important to note that as I have discussed in previous blogs there is a strong link between serious mental illness and metabolic disease such as cardiovascular disease.

Of course, this doesn't prove that a traditional Arctic diet prevents depression or other mental illnesses. The paper is a review of the available evidence and the authors were proposing that this link needs further investigation. There are many differences between traditional and modern lifestyles that could potentially explain the changes in health, including physical activity, sleep, social connection, exposure to nature, alcohol use and socioeconomic factors.

Nevertheless, perhaps the dietary element deserves much more attention.

What might the brain and mental health be affected by diet?

The brain is an extraordinarily metabolically active organ. It requires a constant supply of energy and a wide range of nutrients to maintain neurotransmitter production, cell membranes, mitochondrial function and the complex signalling systems that allow our neurons to communicate. It therefore makes sense that the quality of the raw materials we provide through our diet could influence how well the brain functions.

A diet based around fish, meat, eggs and other animal foods, together with seasonal plants and berries, provides a very different nutritional environment from a modern diet dominated by ultra-processed foods, refined carbohydrates and industrially formulated fats.

This doesn't mean that everyone needs to eat an Arctic diet and traditional circumpolar diets varied considerably depending on location, season and food availability. The important point is the quality and nutrient density of the food.

Traditional diets were not simply about avoiding certain foods. They provided the body with abundant protein, essential fatty acids, vitamins and minerals while generally containing far fewer refined carbohydrates and ultra-processed foods.

Today, we are facing an epidemic of metabolic disease alongside an epidemic of mental ill health. These are often treated as completely separate problems, yet they share many biological pathways. Insulin resistance, inflammation, oxidative stress, mitochondrial dysfunction and disturbances in energy metabolism have all been implicated in both metabolic and mental health disorders.

Perhaps, therefore, we should be looking more closely at the possibility that diet could be one of the bridges connecting the two.

The Arctic provides an interesting natural experiment. Populations adapted to an extreme environment over generations, with food systems that were very different from the modern Western diet. As those food systems changed, so did patterns of physical and mental health. Traditional diets were not necessarily perfect and at times food was likely scarce and difficult to come by. But perhaps those studying why we have such a huge mental illness epidemic have overlooked one of the most basic things that influences the brain every day—food?

Reference

1. McGrath-Hanna NK, Greene DM, Tavernier RJ, Bult-Ito A. (2003). Diet and mental health in the Arctic: is diet an important risk factor for mental health in circumpolar peoples? – a review. International Journal of Circumpolar Health, 62(3), 228–241.