Written by Sarah Criscuolo MS, RD, LDN, CSN, CPT

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Seasonal Affective Disorder (SAD) is a type of depression that occurs yearly with the changing of the seasons, typically beginning in the fall and/or winter months and subsiding in the spring and/or summer months. Spring/summer SAD is much less common but does occur. SAD is categorized by the DSM-5 as a variant of major depressive disorder or bipolar disorder with a seasonal onset and remission. Symptoms of typical depression include decreased energy, depressed or impaired mood, and guilt or hopelessness, while those of bipolar disorder include mania or hypomania, hyperactivity, anxiety and depression. Winter SAD includes these and some atypical features, such as increased need for sleep, extreme fatigue, increased appetite and carbohydrate cravings.

It is estimated that 1-2% of the US population suffers from SAD each year, with symptoms present for about 40% of the year. Possible risk factors for the development of SAD are family history of SAD, female sex, young adulthood (ages 18-30), and living in a northern latitude region.

Although light therapy, cognitive behavioral therapy and pharmacotherapy are all common interventions, there is no gold standard for treatment. Here are some potential treatment options that you can implement on your own this season.

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Nutritional Interventions

Vitamin D

Low levels of vitamin D have been linked to depression in many studies over the years. Vitamin D is necessary for the activation and synthesis of serotonin, the “feel good” hormone, through its precursor, tryptophan. Serotonin is one of the most important neurotransmitters in the body in association with mood and wellbeing. Therefore, if vitamin D levels are inadequate, serotonin levels will be decreased as well, which can lead to depressive symptoms.

Sunlight is the main way that our body synthesizes vitamin D. However, during the winter months, we often are exposed to much less sunlight than usual, which can lead to deficiency. One simple way to increase your vitamin D levels is through supplementation. According to the National Institutes of Health, the recommended daily allowance of vitamin D is 600 IU, or 15 mcg, for adults over the age of 19. Vitamin D supplements can be purchased over the counter at most pharmacies and grocery stores, and vitamin D is also often included in this amount or more in multivitamins.

You can obtain the most easily absorbable form of vitamin D through various animal food sources, such as fatty fish (salmon, mackerel, tuna, etc.), egg yolks and beef liver. Some foods, such as cow’s milk and plant milks, are typically fortified with vitamin D, as well.

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Omega-3s

Omega-3s are a form of polyunsaturated fats that have been linked to decreases in LDL (the “bad” cholesterol) levels and increases in HDL (the “good” cholesterol) levels. They can also help to decrease inflammation, and are important for neural function. Low levels of omega-3s in the diet can lead to cognitive impairment, altered memory, and the development of major depressive disorder.

Omega-3s can be introduced via supplementation, or through various food sources, such as plant oils (like olive or canola oil), fatty fish, nuts (especially walnuts), and chia or flaxseeds.

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B Vitamins

The B vitamins, which include folate, riboflavin and biotin, are known to be essential for energy production in the body. As fatigue is a common symptom of depression, low energy availability can exacerbate this issue. B vitamins can be supplemented via multivitamins or a B-complex supplement. They are also found in animal products such as meat, liver, kidney and eggs, as well as many grains and legumes.

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Other Interventions

Light Therapy

As mentioned previously, vitamin D is important for the activation and synthesis of serotonin in our bodies. In areas of the world that experience winter, people are exposed to much less sunlight than in the warmer months, decreasing the levels of vitamin D made by the body. One research-backed way to counteract this is using broad spectrum light therapy. Light that falls between the wavelengths of 280-320 nm allows the body to produce vitamin D. SAD lamps can be purchased online, and the following are the general recommendations for appropriate usage:

• Choose lamps that provide 10,000 lux of light
• Use within the first hour of waking in the morning
• Use for 20-30 minutes per day
• Keep the lamp about 16-24 inches from your face
• Have your eyes open while using the lamp, but don’t look directly at it

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Human Connection

Humans are innately social beings, meaning that it is in our nature to crave interaction with others. Studies have found that prosocial interactions lead to the release of serotonin and dopamine, two important “happy” hormones. It can also stimulate the release of another hormone, oxytocin, which enhances empathy and promotes trust. Given this information, experiencing positive human connections can create a cocktail of feel good hormones, boosting mood and potentially alleviating some of the symptoms of SAD. At difficult times, it’s important to keep those who you care about close and utilize your support system.

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Self-Care

Whether you’re someone who enjoys going out or staying in, doing things that bring you joy is extremely important during the months that you deal with SAD. Journaling, listening to music, creating art and reading are all examples of self-care hobbies that can help to release dopamine and serotonin, improving mood and keeping you present. Some options that can get you out of the house are going for a massage, a relaxing drive, or doing some shopping.

Movement is also a form of self-care, and many people find exercise to be very therapeutic. Find activities that bring you joy rather than compulsive exercise, and try to take part in them for 75 minutes per week if they’re vigorous, or 150 minutes per week if they’re moderately difficult.

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If you’re struggling with SAD, know that you’re not alone. In conjunction with a licensed therapist, a registered dietitian can be a great asset to your care team, providing options for ways to change your diet and supplement regimen in order to improve your emotional wellbeing. Use this link to schedule a free intake call today!

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Sources:

1. Yang Y, Zhang S, Zhang X, Xu Y, Cheng J, Yang X. The Role of Diet, Eating Behavior, and Nutrition Intervention in Seasonal Affective Disorder: A Systematic Review.

2. Frontiers in Psychology. 2020;11. Accessed December 8, 2023. https://www.frontiersin.org/articles/10.3389/fpsyg.2020.01451

3. Galima SV, Vogel SR, Kowalski AW. Seasonal Affective Disorder: Common Questions and Answers. afp. 2020;102(11):668-672.

4. Petric D. The Importance of Vitamin D in Seasonal Affective Disorder and Other Depressive Disorders. International Journal of Medical Reviews and Case Reports. 2021;5(13):48-50.

5. Office of Dietary Supplements – Vitamin D. Accessed December 8, 2023. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
Seasonal affective disorder treatment: Choosing a light box. Mayo Clinic. Accessed December 8, 2023. https://www.mayoclinic.org/diseases-conditions/seasonal-affective-disorder/in-depth/seasonal-affective-disorder-treatment/art-20048298

6. Duerler P, Vollenweider FX, Preller KH. A neurobiological perspective on social influence: Serotonin and social adaptation. Journal of Neurochemistry. 2022;162(1):60-79. doi:10.1111/jnc.15607