Dreary winters are infamous for inducing depression, but research suggests that not getting enough sunlight can do more make you feel down in the dumps.

According to The Seattle Times, evidence suggests that lack of sunlight can raise your risk of cancer and increase susceptibility to heart attack, diabetes and multiple sclerosis.

The reason?  You’re missing out on vitamin D, an essential nutrient produced in abundance by skin exposed to the sun’s rays. The so-called “sunshine vitamin” is now recognized as a key player throughout the body, including the immune system, the Times said.

Increased use of sunscreen has turned a seasonal shortfall into a year-round condition for many people. A recent survey in Britain found 87 percent of adults tested during winter, and more than 60 percent in summer, had sub par vitamin D levels.

Doctors in many parts of the world report a resurgence of childhood rickets, soft bones caused by lack of vitamin D, says the Times.

Supplements offer a cheap and easy solution. But Bruce Hollis, a leading vitamin D researcher at the Medical University of South Carolina, and other researchers argue the recommended intake is too low to provide many health benefits.

A Canadian medical organization advises that pregnant and nursing women take 10 times the amount suggested in the U.S., the Times reported.

“You’re more likely to live longer, and you’re less likely to die of serious chronic disease if you have adequate vitamin D on board,” said Michael Holick of Boston University School of Medicine. “It may well be the most important nutrient of the decade.”

Vitamin D in your diet
- The U.S. Institute of Medicine recommends 200 IU a day up to age 50 and 400 to 600 IU for older people.
- The Canadian Pediatric Society recently urged pregnant and nursing women to take 2,000 IU a day.
- Exposing just your arms and legs to the summer sun for less than 15 minutes can generate 5,000 IU.
- It is possible to go overboard with supplements and trigger dangerous calcium deposits in kidneys and blood vessels, but Michael Holick of Boston University School of Medicine says it takes a lot: more than 10,000 IU a day for a year.
- Milk and some cereals are fortified with small amounts of vitamin D to prevent rickets, but few foods are significant natural sources.