Treating Seasonal Depression: A New Option

Do you suffer from the blues once the weather turns glum and chilly? You may have seasonal affective disorder (SAD), a form of depression that typically hits in the winter months and causes irritability, restlessness, feelings of hopelessness, and difficulty concentrating and sleeping.

Itís not clear what causes SAD, but researchers at the University of Georgia are suggesting that low levels of vitamin D, the so-called sunshine vitamin (it is manufactured by the body in response to exposure to the sunís radiation), may be linked to an increased risk of SAD. Not getting enough sunlight may actually wreak havoc with the bodyís ability to regulate mood and sleep, say the authors of a Medical Hypotheses article.

Itís an intriguing idea. "Low vitamin D intake can be related to seasonal affective disorder," says Alan Manevitz, MD, clinical psychiatrist at Lenox Hill Hospital in New York City. "Itís a critical vitamin that is involved in regulating many functions the body, and it plays a role in synthesizing dopamine and serotonin in the body." These mood-regulating neurotransmitters (chemical messengers that modulate and carry signals between nerve cells and other cells in the body) could actually become unbalanced in the body when a person doesnít get enough sunlight according to the researchers.

All About Vitamin D

Vitamin D is vital for many functions in the body: "If you donít have enough vitamin D, you may not absorb calcium correctly," says New York City-based registered dietician/nutritionist Keri Gans, MS, RDN, CDN. This could ultimately lead to osteoporosis [thinning and weakening of the bones], she explains. Additionally, "Itís not conclusive, but vitamin D may help in the prevention of type 2 diabetes."

Getting Enough Vitamin D

If you suffer from SAD, a dose of vitamin D may be just what you need. But this doesnít mean you should start popping vitamin D before checking your levels with a doctor, Manevitz says.

A blood test can tell you if youíre lacking in vitamin D; levels should be between 50 and 125 nanomoles per liter (nmol/L) of blood, according to the National Institutes of Health Office of Dietary Supplements. If your levels are normal, there is no reason to take more, since "Taking a megadose of vitamin D could lead to toxicity," Gans points out. According to the Office of Dietary Supplements, the upper safe limit for daily vitamin D intake is 4,000 IU, or international units. (This applies to people ages 9 and up; infants and children should take less.)

But if you are low in vitamin D, youíll most likely require a supplement, as it can be difficult to get enough of the vitamin from food, Gans says. Vitamin D is most abundant in fatty fish like salmon, canned tuna, and sardines (and cod liver oil), though certain foodsólike milk, and some cereals, yogurts, and orange juicesóare fortified with it. The Institute of Medicineí Food and Nutrition Board recommends people between the ages of one and 70 get an average of 600 IU a day.

Other Suggestions for SAD Patients

If you are suffering from SAD, Manevitz suggests these remedies:

  • Make sure to stay well-hydrated.
  • Avoid alcohol, which can make you dehydrated.
  • Donít isolate yourself. Instead, participate in a variety of activities and make sure to get enough exercise. If you can get outside even for just a few minutes a day, youíll get some natural vitamin D.

Some medical experts recommend using a light box. These boxes, which typically are used for at least half an hour every morning, contains white light that mimics outdoor light and may cause a mood-lifting chemical change in the brain. Available over the counter, theyíre also called phototherapy boxes or bright light therapy boxes. The non-profit Center for Environmental Therapeutics recommends choosing a product that provides at least 10,000 lux of illumination.

So if youíre suffering from SAD, speak to your doctor about your options.

Keri Gans, MS, RDN, CDN, reviewed this article.

Sources Keri Gans, MS, RDN, CDN. Phone interview December 23, 2014.

Alan Manevitz, MD. Phone interview. December 22, 2014.

Stewart, Alan E. Kathryn A. Roecklein, Susan Tanner, Michael G. Kimlin. "Possible Contributions of Skin Pigmentation and Vitamin D in a Polyfactorial Model of Seasonal Affective Disorder." Medical Hypotheses 2014 83(5):517-525.

"Seasonal Affective Disorder." MedlinePlus/U.S. National Library of Medicine. Page last updated December 30, 2014.

"Vitamin D." National Institutes of Health Office of Dietary Supplements. Page last reviewed November 10, 2014.

"Vitamin D: Fact Sheet for Consumers." National Institutes of Health Office of Dietary Supplements. Page reviewed June 24, 2011.

"Vitamin D: Fact Sheet for Health Professionals." National Institutes of Health Office of Dietary Supplements. Accessed May 10, 2016.

"Light Box Selection Criteria." Center for Environmental Therapeutics. Page accessed January 22, 2015.