As the season shifts and the days get darker, sometimes our moods follow suit. For some of us, the fall and winter bring on a more somber state, with unwelcome winter blues. This phenomenon is known as Seasonal Affective Disorder (SAD), a form of depression triggered by the lack of sunlight that begins and ends around the same time each year. Let’s explore what we can do to feel better and lighter this season with healthy solutions for holiday SADness.
Symptoms of seasonal SADness
Seasonal affective disorder (SAD) is a form of depression which affects some people from fall through the winter months. Since it’s related to shorter days with less sunlight, it’s more prevalent in areas further from the equator (1).
Common symptoms of SAD include:
- Dip in mood and energy levels: feeling low or sad most of the day, every day.
- Decreased motivation: or lack of interest in things typically enjoyed.
- Sleep difficulties: trouble getting to sleep, staying asleep, wanting to sleep much longer than normal, or taking long naps during the day.
- Lower self esteem: or feeling hopeless or not worthy.
- Appetite and weight changes: increased appetite or cravings, typically for sweet or high carb comfort foods.
If you think you may be struggling with SAD, reach out to your physician or mental health provider for more support.
What causes SAD?
While scientists don’t fully understand the cause of SAD, it’s most often linked to reduced exposure to sunlight as the days become shorter and darker. That’s why your friends who live further north may be more likely to complain of symptoms of SAD.
But how do shorter, darker days result in the symptoms we listed above? The leading theory behind SAD is that the lack of sunlight - or reduced exposure to sunlight - impacts critical brain pathways, affecting the following:
- The production of melatonin: Melatonin is known as the sleep hormone. It’s also known as the “hormone of darkness”. Why is that? The pineal gland produces melatonin in response to darkness (2). More darkness during the winter months, leads to higher production of melatonin, resulting in sleepiness and fatigue.
- The production of serotonin: Serotonin is a neurotransmitter, or brain chemical, which helps regulate our mood and other factors such as sleep (5). Studies indicate there is a relationship between sunlight exposure and production of serotonin (3). As a result, a lack of sunlight may lead to lower serotonin, linked to symptoms of depression
- Our circadian rhythm: The body uses sunlight as a cue. Changes to light exposure in the winter can delay our circadian rhythms due to changes related to our sleep wake cycles, another potential driver of depression (4)
Serotonin, melatonin, and our circadian rhythm are all deeply interconnected - and all three impacted by sunlight. As a result, it makes sense that changes to light and dark patterns in the Winter months can result in SAD symptoms. Unsurprisingly, that is likely why the Mayo Clinic reports higher instances of SAD are common the further north you go.
What makes SAD worse?
We have now established that SAD is a result of changes to sunlight exposure. That being the case, there are also a number of factors that can contribute to and worsen SAD symptoms.
Lack of vitamin D
A lack of vitamin D may make SAD symptoms worse. That’s because vitamin D is believed to encourage the release of serotonin. Since our bodies produce vitamin D when our skin is exposed to sunlight, it can make it difficult for our bodies to produce as much serotonin during the winter months. Vitamin D levels tend to be lowest in March after a winter of darker, colder days with less sun exposure (5). Measuring your vitamin D blood level and supplementing with the precision dose to optimize blood levels is a great way to support a healthy mood.
We all respond to stress differently but the holidays tend to serve an extra helping of things to worry about. For our bodies to create serotonin, we need B vitamins, magnesium and vitamin C. Too much stress can deplete these from our body and potentially impact mood. Reduced nutrients also mean we’re more likely to feel tired and get sick more often. Optimizing your micronutrients levels can support neurotransmitter production.
Unbalanced gut bacteria
Our microbiome is a community of microorganisms that live in and on our bodies. They have a major impact on our health and wellness. Consuming excess amounts of sugar and alcohol (hello holiday festivities) can lead to a negative imbalance. Since the helpful bugs produce serotonin, unbalanced gut bacteria can impact our mood (6).
Depression and fatigue is associated with chronic inflammation (10). Increased inflammation leads to more permeability of our blood brain barrier, allowing harmful inflammatory molecules to enter into and impact our central nervous system. Inflammation can also interfere with how efficiently serotonin works in our brains. Measuring inflammatory markers like c-reactive protein can help uncover the root cause of mood changes.
How to naturally treat SAD
Getting light whenever possible and focusing on intentional nutrition and supplementation can support our bodies in naturally producing serotonin and improving symptoms of SAD:
The power of light
Outdoor light is 1000 times brighter than indoor light, which powerfully stimulates the photoreceptors in your brain to make necessary neurotransmitters and hormones for wellbeing. Exposing yourself to morning light will make you feel more alert and help ease you into sleep in the evenings (11). Aim for about 5-10 minutes on a sunny day or 10-15 on cloudy days, without sunglasses. Plus getting outside and moving will stimulate healthy cortisol levels, serotonin, and dopamine; meaning you’ll feel motivated and ready to take on the day!
Since we produce vitamin D when exposed to sunlight, it can be one of the best supplements to have during the autumn and winter months, if you don’t have much access to the sun. Vitamin D comes in many forms with D2 (ergocalciferol) and D3 (cholecalciferol) getting the most attention. The Institute of Medicine claims that D2 is just as effective as D3 while other studies say Vitamin D3 is the best vitamin to look for (7). Learn more here: Vitamin D: The Sunshine Vitamin.
- Vitamin D2: cremini mushrooms, portobello mushrooms, button mushrooms.
- Vitamin D3: oily fish (salmon, sardines, tuna fish), eggs, dairy and orange juice fortified with vitamin D, beef liver.
Omega-3 fatty acids are essential to our brain function and one of the best vitamins for stress. In fact, a number of studies are showing that omega-3 is proven to be an effective treatment against depressive disorders (8). Omega-3 can increase levels of serotonin, helping to fight against those winter blues. In addition to high quality supplements, omega-3 is found in some specific foods.
- Omega-3: salmon, mackerel, cod liver oil, flaxseeds, chia seeds, walnuts.
Pro and prebiotics
Gut bacteria create about 95% of your body’s serotonin supply. To keep the community healthy, aim to limit sugar and alcohol while upping probiotics (live microorganisms we can consume) and their fuel source, prebiotics.
- Probiotics: yogurt, sauerkraut, kimchi, kombucha, pickles.
- Prebiotics: garlic, onions, asparagus, bananas, Jerusalem artichokes.
Food and supplements aren’t the only way to help symptoms of SAD. There are also healthy habits which can increase vitamin D and serotonin, naturally.
- Light therapy: use a light box every day for about 30 minutes in the morning to regulate sleep and wake cycle during the winter.
- Exercise: physical activity can trigger a release of serotonin. Aim for 150 minutes or 2.5 hours of moderate aerobic activity, or 75 minutes of vigorous activity per week (6).
- Stress management: try these 3 Meditation Practices to Reduce Stress.
To help prevent and improve the winter blues, lead with the power of light, whether that’s getting outdoors or using a light box. Then, focus on a healthy lifestyle and diet with supplements such as vitamin D, omega-3, and pro and prebiotics. Always check in with a doctor if you’re experiencing depressive symptoms for an extended period of time or if they interfere with your ability to work or do daily activities.
- Roecklein, Kathryn A, and Kelly J Rohan. 2005. “Seasonal Affective Disorder: An Overview and Update.” Psychiatry (Edgmont (Pa. : Township)) 2 (1): 20–26. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3004726/.
- Masters, A., Pandi-Perumal, S. R., Seixas, A., Girardin, J. L., & McFarlane, S. I. (2014). Melatonin, the Hormone of Darkness: From Sleep Promotion to Ebola Treatment. Brain disorders & therapy, 4(1), 1000151. https://doi.org/10.4172/2168-975X.1000151
- Sansone, R. A., & Sansone, L. A. (2013). Sunshine, serotonin, and skin: a partial explanation for seasonal patterns in psychopathology?. Innovations in clinical neuroscience, 10(7-8), 20–24.
- Lewy, A. J., Emens, J. S., Songer, J. B., Sims, N., Laurie, A. L., Fiala, S. C., & Buti, A. L. (2009). Winter Depression: Integrating mood, circadian rhythms, and the sleep/wake and light/dark cycles into a bio-psycho-social-environmental model. Sleep medicine clinics, 4(2), 285–299. https://doi.org/10.1016/j.jsmc.2009.02.003
- “NIMH» Seasonal Affective Disorder.” n.d. Www.nimh.nih.gov. https://www.nimh.nih.gov/health/publications/seasonal-affective-disorder.
- Aaldijk, Emma, and Yannick Vermeiren. 2022. “The Role of Serotonin within the Microbiota-Gut-Brain Axis in the Development of Alzheimer’s Disease: A Narrative Review.” Ageing Research Reviews 75 (March): 101556. https://doi.org/10.1016/j.arr.2021.101556.
- Romagnoli, Elisabetta, Maria Lucia Mascia, Cristiana Cipriani, Valeria Fassino, Franco Mazzei, Emilio D’Erasmo, Vincenzo Carnevale, Alfredo Scillitani, and Salvatore Minisola. 2008. “Short and Long-Term Variations in Serum Calciotropic Hormones after a Single Very Large Dose of Ergocalciferol (Vitamin D2) or Cholecalciferol (Vitamin D3) in the Elderly.” The Journal of Clinical Endocrinology and Metabolism 93 (8): 3015–20. https://doi.org/10.1210/jc.2008-0350.
- Wani, Ab Latif, Sajad Ahmad Bhat, and Anjum Ara. 2015. “Omega-3 Fatty Acids and the Treatment of Depression: A Review of Scientific Evidence.” Integrative Medicine Research 4 (3): 132–41. https://doi.org/10.1016/j.imr.2015.07.003.
- U.S. Department of Health and Human Services. 2018. “Physical Activity Guidelines for Americans 2nd Edition.” https://health.gov/sites/default/files/2019-09/Physical_Activity_Guidelines_2nd_edition.pdf.
- Berk, Michael, Lana J Williams, Felice N Jacka, Adrienne O’Neil, Julie A Pasco, Steven Moylan, Nicholas B Allen, et al. 2013. “So Depression Is an Inflammatory Disease, but Where Does the Inflammation Come From?” BMC Medicine 11 (1). https://doi.org/10.1186/1741-7015-11-200.
- “Effects of Light on Circadian Rhythms | NIOSH | CDC.” 2022. Www.cdc.gov. May 16, 2022. https://www.cdc.gov/niosh/emres/longhourstraining/light.html#:~:text=Bright%20light%20in%20the%20morning.