The news just keeps getting better about vitamin D. Earlier this year, studies linked proper levels of the "sunshine vitamin" to a decreased risk of diabetes, heart attacks, and cancer; that's in addition to the previously understood role that vitamin D plays in keeping bones strong. Building on all these findings, a new study suggests that maintaining proper levels of the nutrient can even stave off death from heart attacks and other causes. Researchers point out that they haven't yet demonstrated a causal relationship, just a connection.
The study's lead author, Dr. Harald Dobnig of the Medical University of Graz in Austria, said the results don't prove that low levels of vitamin D are harmful "but the evidence is just becoming overwhelming at this point" [AP].
Researchers aren't sure what the connection is but they speculate that the nutrient may play a role in regulating the immune system, and may also have an anti-inflammatory function that keeps the heart healthy.In the new study, which appears in the Archives of Internal Medicine, a team of Austrian researchers
studied more than 3,200 people with an average age of 62 who were scheduled for a heart examination between 1997 and 2000. During an eight-year follow-up programme, the researchers found that the quarter of volunteers with the lowest levels of vitamin D in their blood were more likely to have died [Reuters].
Vitamin D is produced naturally by the skin in response to the sun's ultraviolet rays, and occurs naturally in a few foods, primarily fatty fish like salmon and tuna. Milk products and breads are often fortified with the vitamin, but some researchers now say that people living in northern latitudes might consider taking vitamin D supplements in the winter, when the low-hanging sun's ultraviolet rays don't penetrate the atmosphere.
Despite all the good news, doctors still don't recommend getting a lobster-red sunburn or even a deep brown tan, citing the well-known risks of skin cancer.
If you're fair skinned, experts say going outside for 10 minutes in the midday sun—in shorts and a tank top with no sunscreen—will give you enough radiation to produce about 10,000 international units of the vitamin [U.S. News and World Report]. Dark-skinned people and the elderly produce less vitamin D, and should stay out in the sun a bit longer.
In an article accompanying the research, the researchers report that on average both older and younger people around the world may not be getting enough vitamin D. They speculate that it may be due to air pollution, a lack of outdoor activities, and increased urbanization, with more people staying and working indoors [WebMD].
Image: flickr/Phillie Casablanca
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