Seasonal Affective Disorder Vitamin D: Can It Really Help?

Seasonal Affective Disorder Vitamin D: Can It Really Help?
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Seasonal Affective Disorder

Fighting the Winter Blues

Seasonal affective disorder, also known as SAD, is a mood disorder characterized by noticeable mood shifts during the winter. The disorder typically persists from the autumn equinox until sunlight hours increase again in the spring. People who are affected may experience low energy, poor concentration, depression, anxiety and weight gain. In some regions, such as the Northeast United States, as much as 50 percent of the population may be affected.

The most noticeable aspect of seasonal mood disorder is the decrease in sun exposure. There are fewer hours of sunlight and with the cold temperatures, plenty of reason to choose indoor activities rather then a brisk walk outside. As sunlight is needed for healthy vitamin D levels, this can lead to huge portions of the population in certain areas having a vitamin D deficiency. When it comes to seasonal affective disorder, vitamin D is what you need.

Vitamin D and Sun Exposure

One of the body’s main sources of vitamin D is the sun’s ultraviolet rays. When they hit the skin, a cholesterol compound found in the skin becomes a precursor to vitamin D. Fifteen minutes of sun exposure on the face and arms three days a week is enough for most people to get adequate levels of this nutrient. People with darker skin and more pigment protection from the sun may require more.

Vitamin D is important for the absorption of calcium and phosphorus, for the regulation of the heartbeat, for immune health and normal thyroid function and for the prevention of diseases such as colon cancer, osteoarthritis and osteoporosis. While a vitamin D deficiency is not necessarily a cause of depression, low levels are linked with a higher chance of having depression and with the development of SAD. There are receptors for vitamin D found in the brain. Also, increasing vitamin D levels in the body appears to reduce symptoms.

A study published in the Journal of Nutrition, Health & Aging in 1999 involving 15 participants with seasonal affective disorder found that supplementing with 100,000 IU of vitamin D (do not take this amount on your own) reduces symptoms. All subjects who were given vitamin D experienced noticeable improvements while those who received phototherapy instead did not have significant mood improvements. Other more recent studies, such as one conducted by the researchers at the University of Toronto, have also found that the symptoms of depression and SAD generally improve as vitamin D levels increase.

How Much Is Enough?

Sunlight is not the only source of vitamin D. Excellent food sources include eggs, dairy products and fatty fish, such as mackerel and salmon. Dandelion greens, oatmeal, sweet potatoes, halibut, oysters and shiitake mushrooms also contain some of this nutrient. Including these foods in your diet is a great way to supply the body with natural vitamin D.

Is supplemental vitamin D good for seasonal affective disorder? You can talk to your doctor about taking supplements during the winter. Always take along with calcium. Do not take in excess as too much can have a detrimental affect, including a decrease in bone mass. To be safe, never take more then 1,000 IU per day. Taking a natural, high-quality vitamin D supplement of 400 IU during the darker, winter months should be enough. Always talk to your doctor before taking any nutritional supplements, especially if you are taking any form of medication or if you have a medical condition.

Other Tips for Treating the Winter Blues

Vitamin D can definitely play an invaluable role in the treatment of seasonal affective disorder. There are other steps you can take as well to

Salmon for Vitamin D and Omega 3

help improve your mood and reduce symptoms until spring arrives. Focus on your diet. Eat plenty of whole grains, nuts and seeds for nourishing complex carbohydrates and to control sugar cravings. Legumes, fruits and vegetables are also important. Omega-3 fatty acids, found in fish, walnuts and supplements, such as flax seed oil and fish oil, are also important.

Herbs can also help relieve the symptoms of SAD. A cup of lemon balm tea, drunk regularly, is excellent for easing depression during the winter. Taking St. John’s wort extract or capsules can also help. This herb should not be taken if you are taking antidepressants or are pregnant. To help with energy levels, ginseng and gotu kola can help. Always discuss the use of herbal medicine with your doctor before use.

Another tip for seasonal affective disorder — get outdoors. Outside exercise such as walking or running on days that are not too cold can really help. If possible take advantage of the waning sunlight hours. Consider winter sports such as skiing. If possible, go south for a little vacation during the winter. Spending even a short amount of time in a warmer, sunny environment can reduce symptoms upon return for up to one month.


US National Library of Medicine. “Vitamin D vs broad spectrum phototherapy in the treatment of seasonal affective disorder.”


Balch, Phyllis A. “Prescription for Nutritional Healing.” Fourth Edition (Penguin Books, 2006).

Page, Linda. “Healthy Healing: A Guide to Self-Healing for Everyone, 11th Edition” (Traditional Wisdom, 2003).

photo by D Sharon Pruitt/flickr

photo by Khairil Zhaifri/flickr


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