By Maureen Williams, ND
Healthnotes Newswire (January 17, 2008)—The vitamin best known for strengthening the bones is now being recognized for its effect on a softer organ: the heart. A new study links low vitamin D levels to cardiovascular events including heart attack and stroke.
Vitamin D’s important role in getting dietary calcium absorbed and kept in the bone matrix has been recognized for decades. Vitamin D deficiency in childhood, known as rickets, is characterized by severe bone malformations and muscle weakness. As a result of public policy aimed at preventing rickets, most commercial dairy foods are fortified with vitamin D.
In adults, however, the symptoms of vitamin D deficiency are not as obvious. There is evidence that as many as one-quarter to one-third of adults do not have optimal levels of vitamin D, yet the vast majority have no clear symptoms. The predominant source of vitamin D is our own sun-exposed skin cells, but more and more people are covering up and wearing sunscreen, diminishing their ability to make the vitamin.
The consequences of low vitamin D levels in individuals and society could be far-reaching. Research suggests that adequate vitamin D is needed to prevent osteoporosis, and low levels might increase the risk of seasonal depression and some cancers, as well as high blood pressure, heart attack, stroke, and heart failure.
The latest study, published in Circulation, looked at the vitamin D status of 1,739 white adults who were free of heart disease at the beginning of the study. They were monitored for cardiovascular events—heart attack, coronary insufficiency (chest pain caused by low blood flow to the heart muscle), angina, stroke, transient ischemic attack (TIA, sometimes called “mini-stroke”), leg pain when walking, due to poor circulation (peripheral claudication), and heart failure—over an average of about seven and a half years.
People with low vitamin D levels were twice as likely to have a cardiovascular event as people with normal levels, and the risk was highest in people with high blood pressure plus low vitamin D levels.
“It makes sense that vitamin D would be important to cardiovascular health, as we know that vitamin D receptors exist in blood vessel walls and in the heart muscle itself,” commented Lorilee Schoenbeck, a naturopathic doctor who practices in Burlington, Vermont. “Americans living in latitudes north of Boston rarely receive adequate sunlight to produce enough of their own vitamin D. In fact, the Canadian Cancer Society recommends 1,000 IU of vitamin D daily for cancer prevention among Canadians, owing to their lack of sunlight. The more we learn about vitamin D, the more we realize its importance in just about every bodily tissue.”
(Circulation 2008;117:online publication)
Maureen Williams, ND, received her bachelor’s degree from the University of Pennsylvania and her Doctorate of Naturopathic Medicine from Bastyr University in Seattle, WA. She has a private practice in Quechee, VT, and does extensive work with traditional herbal medicine in Guatemala and Honduras. Dr. Williams is a regular contributor to Healthnotes Newswire.
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