As Snow Piles Up Vitamin D Levels Fall
If any U.S. city knows snow, it’s Buffalo, New York. Thanks to its proximity to Lake Erie, Buffalo gets many feet of snow every winter. It’s fitting, then, that a press release issued by the University of Buffalo would focus on one of the lesser known side effects of winter weather: dangerously low vitamin D levels.
Vitamin D is a crucial hormone produced in the body through the action of sufficiently strong sunlight—specifically, ultraviolet radiation—striking bare skin. We’ve known for decades that vitamin D is crucial for strong bones. But in recent years scientists have discovered that vitamin D plays many more important roles in the body. In fact, every single different type of cell in the body is studded with receptors for this molecule. That tells scientists that every cell in the body is capable of responding, in some fashion, to the presence—or absence—or vitamin D.
Subsequent research has since piled up like snow in a Buffalo parking lot. The gist is that vitamin D is crucial for everything from resistance to disease, to fighting off cancer, to keeping the heart and blood vessels working properly, to maintaining cognitive function in older people.
The problem is, in northern latitudes (which includes much of North America) sunlight is too weak in winter to drive the body’s remarkable vitamin D-generating process. And, of course, most of us are forced to bundle up against the cold, anyway, so there’s little chance any skin will be exposed to what little sunlight there may be.
The effects of vitamin D deficiency are stealthy, too, so people are unlikely to notice a problem—until it’s too late. “If you’re deficient, you won’t see the health effects for years and it could take months to get your levels back up,” said nutrition researcher Peter Horvath, of the University at Buffalo School of Public Health and Health Professions.
Researchers estimate that up to half of all Buffalo residents suffer from vitamin D insufficiency during the long winters. And up to a quarter are deficient. Being deficient means you don’t even have the bare minimum necessary to maintain healthy bones, let alone a robust immune system. The elderly, pregnant women, and dark-skinned people are most at risk, although anyone is susceptible to deficiency.
Nursing mothers who are insufficient may be unable to supply enough vitamin D to their infants to prevent rickets—a bone disease caused directly by inadequate levels of vitamin D. Dietary sources of vitamin D include irradiated mushrooms (they’ve been through a “tanning bed” to prompt them to make vitamin D), wild fatty fish, enriched dairy, and dietary supplements. Most people will benefit from 1,000 to 2,000 IU vitamin D3 daily.