Beating The Winter Blues
It’s that time of year when darkness descends like a heavy blanket beginning in mid-afternoon in much of the country. For some people, it also brings a desire to stay in bed and wait for spring.
Seasonal affective disorder, or SAD, affects an estimated 6% of Americans, causing depression, lethargy, irritability and a desire to avoid social situations. It can also create an urge to overeat, particularly carbohydrates. As many as 15% of people in the U.S. may have a milder version that includes only some of these symptoms.
Light therapy, using beams many times more intense than normal light, is the most common treatment. But a host of new therapies-from simulating dawn in your bedroom and changing your thoughts through cognitive-behavioral therapy to taking mega doses of vitamin D-are having success in some patients.
Some experts believe the reduced sun exacerbates vitamin D deficiencies. It may also be that SAD has several different causes.
The most extensively studied treatment is sitting before an intense light for 15 to 20 minutes daily. The theory is that when the sun rises later each day, people’s circadian clocks tend to slip later, too, since they’re regulated by light hitting the retina. But because most people have to wake up at the same time year-round, their bodies fall out of sync, which can bring sleep and mood disturbances.
Vitamin D is created by the sun’s rays on the skin, and therefore declines during the winter. Deficiencies have been linked to a wide variety of illnesses, including depression. So it stands to reason that vitamin D might play a role in SAD. Yet the few studies involving vitamin D and SAD patients have had conflicting results.
A 1993 study of 125 Boston women with seasonal mood swings found that those who received 400 international units of vitamin D-2-double the current recommended daily allowance for adults aged 19 to 50-no better than those who got a placebo.
Researchers agree that more study is needed on the effects of vitamin D, and at what doses. Vitamin D can’t be gotten from a light-therapy box, which should screen out ultraviolet-B rays. Midday sunbathers can get plenty of vitamin D in about 20 minutes in the summertime in New York City. But UVB rays are much weaker in the winter. North of a line running roughly from Boston to northern California, between October and March, the sun’s rays aren’t strong enough to provide vitamin D.
While some foods contain vitamin D-particularly fish, eggs, cod liver oil and fortified milk-the most efficient way to get it is with supplements. Some experts recommend getting at least 4,000 IUs of D-3 daily. “There’s compelling evidence that if you are deficient, taking more vitamin D can be very very helpful,” says Dr. Gloth.
Both sunlight and tanning beds do provide UVB rays, which produce vitamin D in the body. There’s also some speculation that UVB rays may stimulate endorphins, a natural hormone that acts like a pain-reducing, pleasure-enhancing opiate in the brain.