When Bill Withers sang "Ain't no sunshine when she’s gone," he was lamenting a broken heart.

Well it turns out when the sunshine vitamin — the big D — is gone (or at least deficient), you are risking a broken heart too.

A first-of-its-kind study published in the European Heart Journal found that people with a vitamin D deficiency were more likely to have high blood pressure and cardiovascular disease (risk factors for heart attack and stroke), and those with the lowest of vitamin D levels had double the risk of heart disease as folks with healthy levels.

This new role for vitamin D in health comes on top of everything else it does for you.

Although we don't know if, in the short term, increasing your vitamin D level into the normal range benefits you, we do know that in the long term if you sustain a level above 35 ng/ml, you're likely to have healthier heart, brain, bone, muscle, and immune-system function, as well as better glucose metabolism.

Around 24% of people in the U.S. have very low levels (below 13 ng/ml) of vitamin D, and another 50% have levels below 35 ng/ml. So you want to get a blood test to see if you're deficient.

You can also increase your intake of oily fish such as salmon and sea trout, and foods (whole grain cereals) fortified with D.

If a blood test shows that you’re still low, take a daily supplement as prescribed by your doctor.