Vitamin D May Ease Depression

Aug. 2, 2004 -- Vitamin D supplementation, shown in recent studies to help lower risk of certain cancers, multiple sclerosis, arthritis, and other conditions, may also relieve depression, according to new research.

Canadian researchers say the benefit of supplementation may come in creating stores of this vital vitamin in the bloodstream to carry people through the dreary months of winter, when a lack of sunlight may lead to or worsen mood disorders -- most notably seasonal affective disorder, the aptly acronymed SAD that affects some 11 million Americans.

Patients with this so-called "winter depression" are advised to treat the condition with a special "light box" that mimics the effects of sunlight during winter months.

Problem From Low Blood Levels?

For this study, published in the July issue of Nutrition Journal, the researchers first identified 130 patients whose blood levels of vitamin D in the summer were considered normal -- about 24 ng/mL. However, some researchers believe that many Americans are vitamin D-deficient and that their blood level may be too low.

"If a patient measures at 24 ng/mL or less in the summer, it will likely drop to 16 ng/mL in the winter because the value you have in the summer is greater than what you'll have in February," says lead researcher Reinhold Vieth, PhD, a vitamin D researcher at Mt. Sinai Hospital in Toronto.

He then gave those patients a questionnaire to gauge their likelihood of depression. Those whose answers suggested a strong possibility of depression were then given supplements containing a daily dose of either 600 or 4,000 international units (IUs) of Vitamin D. They started taking the supplements in summer and continued through the winter.

The patients were re-evaluated a year later. With both doses, patients suffering from depression improved as their vitamin D levels increased to at least 40 ng/mL, what some vitamin D researchers recommend as a normal blood level.

"If I were to provide advice, I would say that anyone in North America should be able to walk into any drug store and buy 1,000 IU vitamin D supplements. And if you consume those supplements every day, you should feel better," Vieth tells WebMD. "It appeared that instead of feeling worse in the winter, they actually felt better with the supplements."

How Much Is Enough?

The Institute of Medicine recommends 200 IU a day up to the age of 50, 400 IU from 51 to 70, and 600 IU over age 70. About 100 IU are found in an 8 ounce glass of fortified milk. Other nutritional sources of Vitamin D include:

• Canned pink salmon: 3 ounces contain about 530 IU of Vitamin D
• Canned sardines: 3 ounces contain about 231 IU of Vitamin D
• Fortified orange juice: 8 ounces contain about 100 IU of vitamin D
• Fortified cereal: 1 serving (about 1 cup) contains about 40-50 IU of vitamin D