For many – especially children, women and the elderly – ''D'' stands for deficiency.
A number of recent studies have found that many people have disturbingly low levels of vitamin D, a vitamin and hormone that helps one’s body absorb calcium and phosphorous.
''Vitamin D deficiency can cause rickets in children and osteomalacia in adults,'' said Shannon Tolbert, a community dietitian with Wellmont Wellcare Health Promotions.
Health officials had all but declared rickets, or softening of the bones, a disease of the past before researchers in North Carolina found 30 cases between 1990 and 1999. Half of those cases appeared in late 1998 and 1999, and all were black children who were breast-fed.
''A lack of vitamin D in breast milk could be the result of a lack of vitamin D in the mother’s system,'' Tolbert said. ''And Vitamin D deficiency is a big problem for darker-skinned people because their bodies synthesize ultraviolet rays from the sun differently.
''The two major ways we get vitamin D are from the sun and food. People aren’t spending as much time in the sun because of skin cancer concerns, and wearing sun block reduces the amount of vitamin D your body can produce from the sun.''
''Food is the best source for getting vitamin D absorption, but it isn’t found in a lot of foods,'' Tolbert continued. ''Since the 1930s, milk has been fortified with vitamin D, and you can find it in fatty fish like salmon and sardines, egg yolks, butter, margarine, some yogurts, cereal bars and infant formula, and now they have started fortifying orange juice.''
However, Tolbert urges anyone considering using vitamin D and calcium supplements to first speak with a doctor.
''There’s still a lot we don’t know about vitamin D, because it just isn’t as researched as some other nutrients,'' she said. ''Vitamin D deficiency and its associated problems aren’t new, but have probably been misdiagnosed because people didn’t realize there was a problem.''