Vitamin D in
Health & Disease By Paul D. Tortland, D.O.
cally, vitamin D is a secosteroid. Derived from cholesterol, vitamin D is formed naturally in the body by the conversion of 17-dehydro- cholesterol in the cell membrane upon exposure of the skin to solar UVB radiation to produce pre-vitamin D3, which then rapidly gets converted to vitamin D3.
V
Steroids are proteins that trigger or signal the cell to perform certain tasks, such as synthesizing other molecules. As a hormone, D is directly or indirectly involved in the expression of over 1000 genes in the body. Many tissues in the body possess signaling molecules only in virtual form; they are encoded in the DNA. These molecules are then synthesized only on demand when signaled. Vitamin D is one of the keys that opens the DNA “library” so the cell can manufacture the necessary proteins and molecules. Without adequate D, the ability of the cell to respond adequately to physi- ologic and pathologic stimuli is impaired. Vitamin D receptors are found in the brain, prostate, breast, colon, muscle and bone tissues as well as in immune cells.
Vitamin D Deficiency Some researchers consider Vitamin D deficiency to be an
epidemic. An estimated one billion people worldwide have either insufficient or deficient levels. It is considered the most widespread deficiency condition in developed nations. In the United States, at least 36% of otherwise healthy Americans are deficient, and over 70% of pregnant and breast-feeding women are deficient, even though they take prenatal vitamins with D! Among postmenopausal women taking osteoporosis medication, over 50% are deficient. And 40-100% of the elderly are deficient.
Actions of Vitamin D
As noted, D is involved in many body functions, and has it im- plications for a wide range of disease conditions.
itamin D is an important vitamin, right? Wrong! Sorry, it’s a trick question. Contrary to popular belief, vitamin D is not a vitamin. It’s actually a hormone. Specifi-
Bone Health The most common role of D involves bone health. Without ad-
equate D, only about 15% of dietary calcium is absorbed. Compared to calcium use alone or calcium with only small amounts of D, adequate amounts of D lead to as much as a 58% reduction in risk for osteoporosis and related fractures.
Muscle Strength Vitamin D is required for maximum muscle function. And D
deficiency has been shown to result in muscle weakness. Raising D levels can improve muscle strength and performance speed. Ad- equate D levels have been shown to reduce the risk of falls in the elderly by as much as 72%.
Cancer There is a growing link between D and cancer. Persons with D
levels below 20 ng/ml are at 30-50% greater risk of Hodgkin’s, co- lon, pancreatic, prostate, ovarian and breast cancers. In the famous Women’s Health Initiative study, women with D levels of 12 ng/ml had a 253% increased risk of colorectal cancer within 8 years. One study estimated that colon and breast cancer in North America could be reduced by 30-50% by raising lifelong D levels to at least 40 ng/ ml.
Diabetes
D supplementation has been shown to reduce the risk of devel- oping insulin-dependent diabetes (Type 1) in children. In one study, over 10,000 children in Finland were given 2000 IU a day of D for the first year of life only. Their risk of developing Type 1 diabetes over the next 31 years was decreased by 80%!
Cardiovascular Disease Low vitamin D level is an independent risk factor for heart
attacks. In a 2008 study, men with D levels greater than 30 ng/ml had a 50% reduced risk for experiencing a heart attack. Vitamin D also has a positive influence on blood pressure, and it helps reduce
36 Natural Nutmeg December 2011
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