Vitamin D & its wonder

The Wonder Vitamin: Vitamin D

Most of us know we need vitamin D for strong bones. Now it appears that this nutrient, or rather a lack of it, may play a role in asthma, cancer, depression, heart disease, diabetes, even weight gain. See why vitamin D may be one of the most important nutrients in your health toolbox, who's at risk for a deficiency, and the safest ways to get enough vitamin D.

Vitamin D allows your body to absorb calcium. Without it, your bones can become brittle and weak. In adults, too little vitamin D can lead to malformed bones and osteoporosis.  In children, vitamin D deficiency once caused many cases of rickets, a bone disease and a major public health problem in the U.S. Fortifying the milk supply with vitamin D virtually eliminated the disorder.

Shown here is a normal spongy bone matrix.

Vitamin D for Heart and Mind

Low blood levels of vitamin D may have effects beyond your bones. Studies find a greater risk of heart problems and a greater risk of depression in older adults. And though it's not clear why, people taking a vitamin D supplement were 7% less likely to die than those who didn't take a daily supplement in one study. In children, researchers have found more severe asthma when vitamin D levels are low.

Vitamin D Comes From Skin

In a perfect world, you'd never have to worry about getting enough vitamin D. Your body produces it on its own. The trick is exposing some portion of your skin to direct sunlight for 15 to 30 minutes a few days a week. But the UV rays that stimulate production of vitamin D can also cause skin cancer. So most experts don't recommend getting your vitamin D from sun exposure.

Vitamin D Where You Live

The darker a person's skin, the more difficult it is to get vitamin D from  sunlight. Fair-skinned people might be willing to risk the 10 to 15 minutes they need to get enough. But there's still a problem. Unless you live south of a line from Los Angeles to Columbia, S.C., there isn't enough sunlight year round to produce all the vitamin D you need. Most people need other sources.

Who's at Risk for "D" Deficiency?

Studies find vitamin D deficiency affects adults, infants, children, and adolescents. Your diet may increase your risk if it's low in milk or the foods that naturally contain vitamin D, such as salmon and eggs. Most people with low blood levels of vitamin D don't notice any symptoms. Others risk factors include:

Obesity

Digestive disorders like celiac disease

Blood Pressure and Vitamin D

The combination of high blood pressure and vitamin D deficiency could be deadly. In one observational study, people with hypertension and a vitamin D deficiency were twice as likely to have a cardiac event than other people in the study. The lack of vitamin D was not linked to cardiovascular problems in those without hypertension.