Have you been finding it difficult to stay positive in the cold, winter months? You’re not alone—the winter blues are quite common for people living in temperate climates—regions of the world that typically experience warm summers and cool winters. For example, roughly 15% of people have been reported to experience the winter blues, which is considered a seasonal subtype of major depression1.
Generally, the winter blues begin to develop as we begin to transition into the fall months and are characterized by feelings of lethargy and overall lowered mood2. In some individuals, these “winter blues” may develop into the medical condition known as seasonal affective disorder (SAD), which occurs in roughly 1-3% of people, and is more prevalent in women compared to men.
What is SAD or seasonal depression?
Seasonal depression is characterized by general feelings of sadness that tend to begin in the fall months and worsen during the depths of winter when daylight hours become significantly shortened2.
Core symptoms include feelings of hopelessness or worthlessness, having low energy, difficulty concentrating, and/or suicidal thoughts19. Additionally, individuals who experience seasonal depression tend to eat more and sleep longer during the winter months2.
As the spring and summer months approach, the feelings of lethargy and sluggishness tend to decrease, which is attributed to the apparent increase in total daylight hours that we experience during these months.
How can I overcome my winter blues?
Although how the winter blues or SAD develops in individuals is not fully understood, there are ways that have been shown to boost mood that you can use to stay positive during the cold, winter season.
Vitamin D and serotonin
Serotonin is considered the key neurotransmitter in regulating mood and wakefulness3. Thus, it makes sense that serotonin would play an important role in the lowered mood that occurs when one experiences the winter blues. Importantly, this may be due to vitamin D deficiency as this vitamin plays a critical role in the production of serotonin4,5. In fact, researchers have associated depressive symptomology with vitamin D deficiency6,7.
Interestingly, our skin generates vitamin D when it absorbs ultraviolet radiation produced by the sun8, implicating a relationship between sunlight, vitamin D, and lowered mood during the winter months.
For this reason, supplementing with vitamin D during the winter months is a direct intervention to combat the lack of sunlight-induced vitamin D we tend to experience6,9.
If you are looking for ways to improve your vitamin D intake through diet, various species of fish (salmon, herring, sardines), egg yolks, and milk are significant sources of food-derived vitamin D. For those looking for vegan options: mushrooms, soy milk, and oatmeal are also great sources of this vitamin.
Bright light therapy
In line with the link between sunlight and mood, it has been suggested that we are currently living in a bright light-deprived society10. And, as mentioned, because this deprivation tends to increase during the winter months, the winter blues have been attributed to a decrease in exposure to natural, bright sunlight.
Accordingly, research has shown that bright light therapy can significantly alleviate symptoms of seasonal depression 11–13. In fact, one study found that depletion of the serotonin precursor, tryptophan, resulted in a significantly lowered mood. However, depleting tryptophan in the presence of bright light (3000 lux) blocked this mood-lowering effect14, indicating the powerful impact that natural, bright light can have on our mood.
Of course, this finding also implicates the role of tryptophan in regulating mood as well.
In fact, it was found that tryptophan supplementation improved mood in individuals that did not respond to bright light therapy, and prolonged the effect of bright light therapy in those who responded to this treatment15. This speaks volumes about the impact of tryptophan on mood and highlights an important synergistic effect in those who respond to light therapy.
One way to boost tryptophan naturally is by adding foods to your diet that are rich in the serotonin precursor. Some of these include: nuts (walnuts, almonds, cashews), seeds (flax, chia, hemp), turkey, and cheese.
It is also possible to boost central tryptophan levels in the brain simply by exercising10, which may contribute to elevated mood, though more studies are required to confirm this link. Nevertheless, a brief walk around the block followed by a bowl of almonds never hurts!
Omega-3 fatty acids
Another way you can improve mood is by boosting the levels of omega-3 fatty acids in your diet. Specifically, omega-3s that are high in eicosapentaenoic acid (EPA), may provide the most benefit in alleviating symptoms of lowered mood associated with depression16,17. Omega-3s can be found in a variety of foods mentioned earlier that also increase vitamin D and tryptophan, but are also found in various plant oils such as flaxseed, soybean, and canola oil.
There is evidence in support of the relationship between food and mood18. Specifically, alterations in your gut microbiota can significantly influence mood state. One way to promote a healthy gut microbiome is by consuming a high-fiber diet. It may also be worth consuming daily probiotics as a direct method to promote healthy, mood-boosting bacteria in the gut.
Of course, each strategy here provides an individual impact on mood, but a combination of each approach may provide optimal benefit to boosting your mood during the winter months! Importantly, it is imperative that you consult a mental health professional if you are experiencing symptoms associated with seasonal depression, especially suicidal thoughts.
Written by Brett Melanson, PhD Candidate in Behavioural Neuroscience (University of Guelph, Canada)
Levitt, A. J., Boyle, M. H., Joffe, R. T. & Baumal, Z. Estimated prevalence of the seasonal subtype of major depression in a Canadian community sample. Can. J. Psychiatry (2000) doi:10.1177/070674370004500708.
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