9 things that can undermine your vitamin D level According to 2011 National Center for Health Data statistics, almost one in three Americans has vitamin D blood levels below 20 nanograms per milliliter (ng/ml), the threshold that the Institute of Medicine (IOM) says is needed for good bone health. Some experts say even higher levels are needed. Figuring out all the factors that can affect a person’s vitamin D levels is complicated. You can get the vitamin from food (mainly because it’s been added; few foods are natural sources of vitamin D) and by taking supplements (many doctors recommend taking 800 IU of vitamin D3 a day). But vitamin D is also produced by the body in a complex process that starts when rays in the invisible ultraviolet B (UVB) part of the light spectrum are absorbed by the skin. The liver, and then the kidneys, are involved in the steps that eventually result in a bioavailable form of the vitamin that the body can use. A review paper about the many factors influencing a person’s vitamin D levels appeared in 2011 in Acta Dermato-Venerologica, a Swedish medical journal. Here are nine interesting factors identified in the paper: 1. The latitude where you live. At higher latitudes, the amount of vitamin D–producing UVB light reaching the earth’s surface goes down in the winter because of the low angle of the sun. 2. The air pollution where you live. Carbon particulates in the air from the burning of fossil fuels, wood, and other materials scatter and absorb UVB rays. Ozone absorbs UVB radiation, so holes in the ozone layer could be a pollution problem that winds up enhancing vitamin D levels. 3. Your use of sunscreen — in theory. Sunscreen prevents sunburn by blocking UVB light, so theoretically, sunscreen use lowers vitamin D levels. 4. The color of your skin. Melanin is the substance in skin that makes it dark. Dark-skinned people tend to require more UVB exposure than light-skinned people to generate the same amount of vitamin D. 5. The temperature of your skin. Warm skin is a more efficient producer of vitamin D than cool skin. 6. Your weight. Fat tissue sops up vitamin D, so it’s been proposed that it might be a vitamin D rainy-day fund: a source of the vitamin when intake is low or production is reduced. 7. Your age. Compared with younger people, older people have lower levels of the substance in the skin that UVB light converts into the vitamin D precursor, and there’s experimental evidence that older people are less efficient vitamin D producers than younger people. 8. The health of your gut. The vitamin D that is consumed in food or as a supplement is absorbed in the part of the small intestine immediately downstream from the stomach. Stomach juices, pancreatic secretions, bile from the liver, the integrity of the wall of the intestine — they all have some influence on how much of the vitamin is absorbed. 9. The health of your liver and kidneys. Some types of liver disease can reduce absorption of vitamin D because the ailing liver isn’t producing normal amounts of bile. Levels of the bioactive form of vitamin D tend to track with the health of the kidneys, so in someone with kidney disease, bioactive vitamin D levels decrease as the disease gets worse. Questions? We are here to help. We carry vitamin D and a host of other supplements to help keep you healthy and assist you in reaching your health goals. Call us today.
Posted on: Tue, 22 Oct 2013 13:23:49 +0000
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