Seasonal blues shouldn’t keep you from making the most of winter. Join us in exploring the science beneath the symptoms to get you back in your prime.

As the holiday season comes to an end, you may notice a change in your mood. You put away the decorations, the kids go back to school, and you get settled back into your normal routine. Anticipating holiday celebrations with family and friends propelled you through the past few months.

But now, something feels different… 

You’re still tired when you wake up. Snowfall outside lacks the romantic quality it had in December; now it just seems like an imposition. Without the holidays to look forward to, the tone of winter changes. Birds migrate south to warmer weather and the mammals go into hibernation. Part of you wishes you could do the same. 

You’re not alone. If it feels like you’re dragging yourself through these winter months, you may have the “winter blues.” An estimated 10 million Americans will experience a more severe subtype known as Seasonal Affective Disorder (SAD). Anyone may develop SAD but women are 4x as likely to be diagnosed (1). Clinicians theorize the gender discrepancy may stem from men feeling apprehensive to report depressive symptoms due to internalized stigma (2). Rates of SAD are highest in the northern hemisphere as there is a significant reduction in sun exposure during the winter months. Here are four key symptoms associated with SAD: 

• Changes in mood; pervasive feelings of sadness, irritability, and hopelessness. 

• Withdrawal from activity; loss of interest in socializing, career, and family life.

• Insomnia and fatigue: you just can’t seem to get enough sleep.

• Appetite changes: more craving for carbs, binge eating, and weight gain. 

If the onset of fall and winter comes with these unwanted symptoms, you may be experiencing seasonal affective disorder (3). We want to reiterate that you are not alone. But you’re likely wondering how a change of seasons can so radically disrupt your emotional state?

Don’t worry, we’ll explain, but let's zoom out for a moment. 

The story of humanity is one project to control the natural world. We constructed houses to withstand the elements, medicine to ward off disease, and fashioned machines capable of crossing oceans in a few hours. We even built rockets strong enough to defy the will of gravity and take us beyond our own atmosphere. The impulse to master our environment makes us human. 

But our great success as a species makes it easy to forget we are still biologically bound to our environment. We haven’t transcended our primal needs. We still require deep sleep, nutritious food, clean water, and social connection. The impact of changing seasons on our mood makes sense when we keep this truth in mind. Except in this case it isn’t a lack of food or water causing SAD… but an absence of sunlight. 

Your parents likely encouraged you to “play outside and get some fresh air,” when you were a kid. Who knew this simple exhortation had such broad implications? Regular sun exposure is essential for optimal health. So much so that public health experts have declared insufficient sun exposure a significant risk factor for a multitude of diseases. Here's what those experts to say: 

“Studies in the past decade indicate that insufficient sun exposure may be responsible for 340,000 deaths in the United States and 480,000 deaths in Europe per year, and an increased incidence of breast cancer, colorectal cancer, hypertension, cardiovascular disease, metabolic syndrome, multiple sclerosis, Alzheimer’s disease, autism, asthma, type 1 diabetes and myopia.”(4)

The prevalence of SAD during winter months owes itself in part due to a significant reduction in available sunlight. Not only are the skies greyer and cloud cover thicker during this time of year, but cold weather keeps us indoors. Many classrooms and offices offer little access to natural light. 

Sunlight kickstarts the cutaneous biosynthesis of Vitamin D. Ultraviolet rays from the sun convert cholesterol (in the form of 7-dehydrocholesterol) to the precursors D₂ and D₃. These precursors, which can also be derived from foods like cod liver oil, fatty fish, eggs, and dairy, are enzymatically transformed into the active vitamin D as 1,25 Dihydroxyvitamin D. (5)

Vitamin D is most known for its important role in calcium metabolism and bone health. But did you know it's actually not quite a “vitamin”… but a steroid hormone? Vitamin D exerts a myriad of “extra-skeletal effects.” Simply put, it does a lot more than just support healthy bones. Vitamin D acts as a potent anti-inflammatory and antioxidant, mediates the parathyroid system, and may even regulate mood. Low levels have been linked to depression, strengthening the link between insufficient sun exposure and SAD. Independent of vitamin D, sunshine increases nitric oxide production which improves circulation and lowers blood pressure. (6, ) 

Another important connection between sunlight and mood involves circadian rhythm. Neurotransmitters and hormones are secreted in a rhythmic fashion. The dance of darkness and light regulates the tempo. If you’ve heard Dr. Huberman discuss the importance of early morning light exposure, he’s referencing this pathway. Sunlight mediates the synthesis of serotonin from tryptophan, and serotonin has a strong effect on mood. Serotonin is a precursor of melatonin, the sleep hormone, which explains why insomnia accompanies SAD. Studies have shown that SAD is associated with lower levels of serotonin in the brain. (7,8)

For most patients, SAD will naturally go away with the arrival of spring and the return of frequent sunshine. While we can’t control the earth's rotation there are some strategies we can implement to attenuate the winter blues. 

Light Therapy: Like sunshine in a box, light therapy can simulate early morning sun exposure. Consistent use of light that provides at least 10,000 lux every morning can significantly improve mood. (9)

Vitamin D Supplementation: Consider supplementing vitamin D to replenish low stores. Preformed supplements come as ergocalciferol(D₂)  and cholecalciferol (D₃). Cod Liver Oil is another excellent source, offering more than 1000 IU of Vit D per tablespoon. Getting levels checked via blood work can support the design of an optimal dosing protocol. (10)

Magnesium Supplementation: Mg deserves a newsletter to itself. Many Americans are chronically deficient in this mineral. Required for the synthesis of active vitamin D and its transport to target tissues, magnesium works synergistically with vitamin D to promote health. (11)

Meditation: Daily mindfulness meditation can improve cerebral blood flow and support a state of neurochemical balance in the brain. Dedicating 5-10 minutes each day in cultivation of mindfulness is a simple strategy that affords great benefits. (12)

Marek Health additionally offers clients exclusive access to a Comprehensive Vitamin and Mineral Panel. To learn more about micronutrient status testing, reach out to your health coaching team today. 

Disclaimer: This blog post/article is for informational purposes only and does not constitute medical advice. This is not a substitute for professional medical advice and should not be relied upon. If you are considering a treatment, always consult your primary care physician to discuss the risks and benefits.

 Citations: 

1. Sunshine, Serotonin, and Skin: A Partial Explanation for Seasonal Patterns in Psychopathology?

2. Men’s Experiences of Mental Illness Stigma Across the Lifespan: A Scoping Review

3. Seasonal sensitivity and psychiatric morbidity: study about seasonal affective disorder 

4. Insufficient Sun Exposure Has Become a Real Public Health Problem. 

5. Evaluation, treatment, and prevention of vitamin D deficiency: an Endocrine Society clinical practice guideline.

6. Extra-Skeletal Effects of Vitamin D

7. Serum vitamin D and sex hormones levels in men and women: The Multi-Ethnic Study of Atherosclerosis (MESA) 

8. Circadian regulation of depression: A role for serotonin. 

9. Light room therapy effective in mild forms of seasonal affective disorder--a randomised controlled study.

10. Effects of vitamin D supplementation on depression and some involved neurotransmitters.

11. Magnesium status and supplementation influence vitamin D status and metabolism

12. Review of the effects of mindfulness meditation on mental and physical health and its mechanisms of action