It seems like everyone is talking about vitamin D these days. As a result of people getting less sun exposure due to climate, lifestyle, and skin cancer concerns, there is a growing epidemic of vitamin D deficiency. According to Dr. Andrew Weil, it is estimated that up to 1 billion people are deficient in vitamin D, commonly referred to as the “sunshine vitamin”.  Vitamin D is a fat-soluble vitamin that many experts classify as a hormone. It mainly functions to keep normal blood levels of calcium and phosphorus and support bone health.

Current research is also pointing to a role in protecting from psoriasis, hypertension, cancer, diabetes, rheumatoid arthritis, and multiple sclerosis. Based on these findings, many healthcare providers have increased their recommendations for vitamin D supplementation to 1,000 IU. Not surprisingly, supplement companies are now formulating products in higher strengths to meet this demand.

There are two forms of vitamin D important to the human body. D3 or cholecalciferol is the form created through skin exposure to the sun’s UVB rays and the preferred form for the body to use. The most common source is cod liver oil and small amounts are also found in sardines, tuna, herring, and mackerel. D2 or ergocalciferol is the form created by plants during photosynthesis. It is usually found in such fortified foods as dairy products, eggs, and cereals. This form breaks down quickly and there is currently a debate over how well it is utilized by the body.

For now, most experts still favor supplementing with D3. Both D3 and D2 are converted in the kidneys to calcitriol, which is the active form of the vitamin. People at risk for vitamin D deficiency include those that are living in industrialized northern latitudes, home-bound or bed-ridden, and darker-skinned. Severe vitamin D deficiency, known as rickets, presents as softening of the bones, leading to easy fractures and deformities. Less severe deficiencies put people at risk for osteoporosis. New research is showing an increased risk of heart attack, depression, and certain cancers associated with low vitamin D levels.

The many roles of vitamin D are slowly being uncovered. Most importantly, it aids in calcium and phosphorus absorption by the body. It is an integral nutrient in bone mineralization and necessary for building bone. This is why you should take vitamin D with calcium to support bone health. There have been many studies validating the importance of maintaining adequate vitamin D levels. According to Dr. Walter Willet, Chair at the Department of Nutrition at Harvard, studies have shown that 700-800 IU of vitamin D daily does seem to reduce fracture incidence. He says there is also evidence suggesting that a higher intake of vitamin D may reduce the risk of prostate cancer, colon cancer, and multiple sclerosis. According to the National Institutes of Health, most adults should get between 200-400 IU of vitamin D per day. To determine if you have a deficiency, you can have your levels tested with a 25-hydroxy vitamin D test.

As the importance of vitamin D comes to the forefront, the dangers of this growing epidemic are obvious. With people getting less sunshine and the difficulty in obtaining enough vitamin D from food sources, supplementation will become more commonplace. There is a prescription strength (50,000 IU) once weekly form of vitamin D available for more severe deficiency. And there are many over-the-counter supplements available in varying forms and strengths. As mentioned, those made with the D3 form are preferable. It is best to take a vitamin D supplement with a fatty meal for maximal absorption.

There is little concern for toxicity with supplemental doses, since the body can make 10,000 to 20,000 IU per day with moderate sun exposure. Getting about 10 minutes a day of direct sunlight on your hands and face can help boost levels. And keep in mind that your body can produce enough vitamin D during the summer months to carry you through the winter. The chatter about vitamin D only seems to be getting louder. As always, be sure to discuss your concerns with your healthcare provider.

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