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Seasonal Affective Disorder: Your Mood Doesn't Have to Fall with the Seasons!

As the leaves start to fall, so does our mood!

Seasonal Affective Disorder, or SAD for short, is a type of lowered mood disorder with depressive symptoms, directly related to the change in seasons. SAD begins around the same time each year, starting in the fall as we start to notice the days getting shorter, and is alleviated in the spring when the sun shines longer during the day.


  • Feeling low mood/depressive symptoms most of the day

  • Losing interest in your favorite activities

  • Daily low energy and fatigue

  • Feeling sluggish, moody, or agitated

  • Slow, foggy brain or difficulty concentrating

  • Oversleeping

  • Increased appetite, sugar and carbohydrate cravings

  • Weight gain

SAD is such a common clinical issue, yet under-supported conventionally. You shouldn’t have to experience these symptoms year in and year out! There are things we can do to ease the discomfort that comes with certain times of the year.


I want to focus on Vitamin D’s role in SAD. Because we live in North America, the northern hemisphere gets significantly less sunshine than the lower hemisphere. Many Canadians are often deficient in Vitamin D, and can experience SAD when the daylight hours become shorter and shorter. Because one way we get Vitamin D is by synthesis in the skin, we need adequate sunlight rays to do so.

Vitamin D is an essential vitamin for overall health, specifically our mood. Although named a vitamin, it truly acts as a neurohormone with multiple functions in the body including immune modulation, insulin sensitivity, neurotransmitter synthesis, calcium uptake and bone health, and autoimmune support in conditions such as MS. Because it has many receptor sites in the brain, it influences mood quite heavily, and low amounts can contribute to depression.


  • Low production due to fewer hours of sunlight (fall and winter time!) because it is synthesized and converted in the skin!

  • Lower intake of foods (fish, eggs, mushrooms, liver) leading to lack of dietary intake

  • Stress! (High cortisol reduces VDR expression and therefore decreases vitamin D uptake and activity in the body)


The Vitamin D receptor (VDR) is present in almost every tissue in the body. VDR sites in the brain up regulate the synthesis of 5-HTP (which converts to melatonin), when vitamin D is bound. Therefore if you don’t have enough vitamin D to bind to these receptors, serotonin synthesis is greatly decreased!

Because vitamin D is a fat-soluble vitamin, it has to be processed by the liver and stays in tissues longer, which means it carries a toxicity risk. Always ensure you are speaking to your health care provider before self-supplementing with Vitamin D in higher doses above the recommended daily intake before having your vitamin D levels checked via bloodwork.


Another influence of mood is due to the melatonin rhythm. As we enter the darker seasons, more melatonin is produced by the body when there is lack of sunlight. To produce more melatonin, we need the precursor tryptophan. But guess what also needs tryptophan to be produced? Serotonin, the happy hormone! So by increasing production in melatonin, it is theorized that there is less tryptophan to produce serotonin and therefore a low serotonin picture is created.


  1. Support vitamin D levels - first testing your blood levels to determine proper dosing and support

  2. Environmental support - creating a bright environment in and around your home to provide the most sunlight exposure during the hours that the sun does shine

  3. Nature time - get outside and expose yourself to sunlight (even on the cloudy days) - to support proper vitamin D production, cortisol and melatonin balance, and overall mood support

  4. Exercise regularly - the biggest benefit for mood with exercise is endorphin release, which are our feel good hormones, that help relieve anxiety, stress, and elevate mood on the slow days

  5. Phototherapy - there are LED light therapy lights that are very beneficial to add into your daily regime to exposure yourself to light. 10,000 lux is the desired level to obtain light therapy. 20-30 minutes, within half an hour of waking, is best!

  6. Increasing Omega 3’s - either in a fish oil supplement (ensuring adequate DHA content, as this is the form that is most beneficial for brain and neurotransmitter health) or in food by increasing omega 3’s in your diet - foods higher in omega’s are things such as cold-water fish, nuts, and seeds

  7. Serotonin supporting herbs & supplements - Magnolia, Phellodendron, 5-HTP, tryptophan, B-vitamins, Magnesium

  8. Medications - sometimes diet, lifestyle, and supplements do not improve how we feel - and that is okay! Medications like SSRI’s or Wellbutrin may be indicated

** always ensure you are speaking with a health care provider before initiating treatment yourself as not all suggestions are deemed safe in every person

Our mood doesn’t always have to fall with the seasons - book in with a Naturopathic Doctor to learn more about supporting healthy hormone levels as we enter the darker months!

Book Online at: or call 250.868.0221

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