Are you getting enough Vitamin D?
If not, you could be putting yourself at increased risk for cardiovascular disease.
It's estimated up to half of American adults have Vitamin D deficiency.
An article this week in the Journal of the American College of Cardiology takes a look at recent research.
In one study, patients with low levels of Vitamin D were twice as likely to have a heart attack or stroke within five years.
Doctor John Schmedtje with the Roanoke Heart Institute says Vitamin D is a very important vitamin for heart health, especially for those who already have risk factors for heart disease or diabetes.
"Certainly the heart and blood vessels are regulated in part by Vitamin D," says Schmedtje.
That includes things like your blood pressure and the thickening of blood vessels.
Researchers says most of the body's requirement can come from sun exposure, but doctors say that relying only on the sun can involve the risk of Skin Cancer.
Food sources of vitamin D include Salmon, Sardines, Cod Liver oil and fortified foods such as milk and cereal.
Supplements are also an option. But how much do you need? It turns doctors don't have a clear idea of how much is enough.
Many physicians are now recommending more than one thousand international units a day. That can be more than most people than most people get in their diet or sun light exposure.
But it doesn't take years for Vitamin D deficiency to start taking its toll.
"I think it could have an effect over a few months, if you have another heart disease problem that's in play," says Schmedtje. "For instance, if you've had a recent heart attack," he says.
Researchers are recommending patients be screened and treated for Vitamin D deficiency.
A screening would involve a blood test.