VITAMIN D
Vitamin D, a fat-soluble vitamin, is essential to regulate the body’s balance of calcium and phosphorus.
Vitamin D promotes calcium absorption in the intestines and helps mineralize the bones properly. A severe deficiency of Vitamin D leads to rickets and osteomalacia, bone diseases causing soft and weak bones. Childhood rickets is uncommon now since milk became fortified with 400 IU (International units) per quart in the 1930’s. Exposure to ultraviolet light (UV-B) in sunshine promotes synthesis of Vitamin D in the skin. People who live in northern latitudes or who get little exposure to sunlight may become deficient in this vitamin.
Vitamin D has an important role to play in keeping bones adequately mineralized and can slow down or prevent osteoporosis (brittle bones of old age). Over 25 million Americans have or are at risk of having osteoporosis.
New research has shown that Vitamin D has other important biologic effects on cell regulation and health. Deficiency of Vitamin D is associated with insulin resistance and may contribute to development of adult diabetes. Insulin resistance and metabolic syndrome (high blood pressure, high blood fats, obesity) are associated with heart disease, the number one killer of American adults.
Vitamin D deficiency is associated with cancer of the breast, colon, prostate, and skin. Low Vitamin D levels may contribute to infertility and premenstrual syndrome.
Low Vitamin D may be part of the puzzling increase in chronic fatigue and depression. Seasonal affective disorder, a depression linked to lack of sunlight during the winter season, has been shown to improve with Vitamin D therapy.
Several autoimmune disorders such as multiple sclerosis, rheumatoid arthritis, thyroiditis and Crohn’s disease are linked with low Vitamin D levels. Intense ultraviolet-B exposure (such as severe sunburn) has been shown to lower immune function but chronic low level exposure boosts immune function. Obesity is also linked to low Vitamin D levels.
The importance of adequate Vitamin D levels to optimal health is clear both from old and newer research. Ingesting excessive Vitamin D from supplements can lead to severe health problems as well. I advise limiting intake from all sources to less than 800 IU unless you have your physician monitor your blood levels periodically. More information about Vitamin D can be found on www.vitaminDcouncil.org and http://www.mercola.com.
Daniel Blodgett MD