Sunday, July 3, 2011

6 New Reasons You Need Vitamin D

Vitamin D is frequently in the news as various studies have shown it potentially fights cancer, reduces heart disease risk, staves off diabetes, and boosts testosterone. Although most of these studies are observational and a cause-and-effect relationship hasn’t been proven, the findings are exciting and serve as a reminder to make sure you’re getting the daily amount of vitamin D recommended by the Institute of Medicine: 600 to 800 international units (IU).

1. Fight melanoma

Vitamin D serves as a signaling mechanism in the body, turning cells on and off, explains the New York Times. That may be the case with cancer cells, scientists speculate, with vitamin D stopping cells from turning malignant. A recent study in which vitamin D appeared to protect women who had had non-melanoma skin cancers from getting the deadlier version gives that theory some weight. However, researchers say their results need to be confirmed in further studies.

"We're not recommending super high doses" of vitamin D, study author Dr. Jean Tang, from Stanford University School of Medicine in Redwood City, Calif., tells Reuters Health. But she adds: "I feel good about saying if you've already had a non-melanoma skin cancer, you're already at risk for developing melanoma in the future, (and) taking a little bit of calcium and vitamin D, while other studies need to be done, seems reasonable and not harmful."

2. Cut heart risk

Vitamin D may be another weapon in the battle against heart disease, the nation’s No. 1 killer. A recently published study by Harvard School of Public Health researchers found that men who took at least the daily recommended amount of vitamin D (600 IU) were 16 percent less likely to develop heart problems or stroke than men who took less than 100 IU. The large study, which followed 119,000 adults for two decades, did not find similar results for women, possibly because women have less active vitamin D circulating in their blood, Reuters Health reports. Vitamin D also is stored in body fat, which women typically have more of.

"The evidence is not strong enough yet to make solid recommendations" regarding dosing, lead research Qi Sun wrote in the American Journal of Clinical Nutrition, according to Reuters Health.

3. Boost testosterone

Men who have adequate levels of vitamin D have higher levels of circulating testosterone, which may boost sexual desire, according to a study in the journal Clinical Endocrinology. Scientists tested the levels of vitamin D and testosterone in 2,299 men over several months. As levels of vitamin D increased, testosterone levels peaked in the summer and fell during the winter. The study also showed that men with at least 30 nanograms of vitamin D per milliliter of blood had higher levels of circulating testosterone.

4. Stave off diabetes

Vitamin D may be a formidable foe against diabetes. Previous studies have shown that vitamin D may play a role in regulating blood sugar, and now a recent study has found that people with lower levels of the vitamin circulating in their blood may have a higher risk of becoming diabetic. Australian researchers followed more than 5,000 people for five years and concluded that participants with lower-than-average vitamin D levels had a 57 percent increased risk of developing Type-2 diabetes compared with participants with blood levels in the recommended range.

"Studies like ours have suggested that blood levels of vitamin D higher than what is recommended for bone health may be necessary to reduce the risk of developing Type-2 diabetes," lead author Dr. Claudia Gagnon, a fellow at the Western Hospital at the University of Melbourne in Australia, tells Reuters Health.

5. Reduce MS risk

The less time you spend outdoors, the more likely it is that you are low in vitamin D because the body makes it in response to sunlight. Studies have found that people who live near the equator have less of a chance of developing multiple sclerosis compared with people living at higher latitudes. That said, an Australian study recently published in Neurology found that people who spent more time in the sun and had higher vitamin D levels were less likely to get multiple sclerosis.

Researcher Robyn Lucas of the Australian National University cautioned that too much sun exposure can lead to skin cancer, but that "small amounts of sun exposure ... occurring frequently, are probably optimal both for maintaining vitamin D levels and for other health effects."

6. Protect against breast cancer

Time in the sun may also cut women’s chances of getting breast cancer, according to a study by Canadian researchers. The work, published in the Journal of American Epidemiology, showed that women who reported spending the most time in the sun during their teens — at least 21 hours per week — had a 29 percent less chance of getting breast cancer than those who spent only an hour a day. The average age of the women questioned was 56; 3,101 were breast cancer survivors and 3,420 had never had breast cancer.

Researchers say vitamin D from the sun’s rays may have an anti-cancer effect, but more study is needed.

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