Vitamin D is a fat-soluble vitamin (meaning it is dissolved in fat) that is produced internally by the body when ultraviolet rays from the sun hit the skin. There are two forms of vitamin D produced by living creatures: D-2 and D-3. Vitamin D-2 is produced by invertebrates, fungus and plants. Vitamin D-3 is produced by human bodies. Therefore vitamin D-3 is generally the most commonly recommended since it is the one our bodies produce.
Vitamin D is essential in calcium absorption in the digestive tract and maintaining proper calcium and phosphate levels which enable mineralization of the bone and bone development. If the body doesn’t have enough vitamin D, bones can become brittle, thin or deformed. It is a component in the prevention of osteoporosis.
Vitamin D has other roles in human health, including proper function of the neuromuscular and immune system and reduction of inflammation, as well as the prevention of breast cancer, colon cancer, prostate cancer, heart disease, weight gain and depression. Deficiencies in vitamin D may also be linked with dementia, including Alzheimer’s. According to the May 2009 issue of the Journal of Alzheimer’s Disease, there is enough evidence to indicate that further research should be done to explore links between vitamin D deficiency and dementia.
Vitamin D is naturally present in very few foods and the only other way to get this vitamin besides supplements, is the sun. But most people don’t want to expose themselves to the sun without protection because of the risk of skin cancer.
So how do you know you’re getting enough? According to the National Institute of Health, levels of D in the bloodstream do not typically decrease until the vitamin D deficiency is severe, so blood tests can be inaccurate. The current recommended daily dose of vitamin D is 200 IU for people up to age 50, 400 UI for people ages 51 to 70 and 600 IU for people over the age of 70. But most scientists and experts agree that just isn’t enough. Boston University Vitamin D expert, Dr. Michael Holick, MD recommends a dose of 1,000 IU a day. The American Academy of Pediatrics recommends at least 400 IU for children from infants to teens. And the Vitamin D Council, a group of respected medical doctors and scientists who are trying to educate people on this nutrient, recommends that healthy adults take 2,000 IU of vitamin D daily.
But can you get too much and how would you know? Too much can cause nausea, constipation, confusion and abnormal heart rhythm. As with any supplement, it is best to consult a competent professional to determine how much you should be taking.
Shelley Jaffe is a Certified Nutritional Consultant and the Executive Director of Peter Gillham’s Nutrition Center in Downtown Clearwater.
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