Vitamin D, not The Magic Bus

24 08 2011

Recently some folks have been touting Vitamin D (and specifically supplementation with Vitamin D3) as the next super supplement to confer immortality. This has been due to some recent information that had suggested a mortality benefit with the consumption of Vitamin D for a variety of conditions. Vitamin D, along with E, A and K, is a fat-soluble vitamin. It is naturally present in a several foods, available by supplementation and also produced by our bodies with exposure to sunlight. Once ingested or produced, Vitamin D undergoes two transformations in the body (called hydroxylation) to form the metabolically active compound.  These occur in the liver and kidneys and yield the physiologically active 1, 25-dihydroxyvitamin D, also known as calcitriol.

Vitamin D acts to help regulate calcium and phosphorus metabolism. This is important for a number of functions including bone formation and maintenance, immune function, cell growth, inflammation modulation, neurological function and proper muscle functioning. Daily intake recommendations vary with age but for most adults are on the order of 600 IU (15 micrograms) per day. Foods rich in Vitamin D include fatty fish like salmon and tuna, organ meats like liver, cheese and eggs. Common fortified foods are milk, yogurt, ice cream and orange juice. Recent interest had focused on oral supplementation with Vitamin D3 (cholecalciferol), generally produced by the irradiation of 7-dehydrocholesterol from lanolin and the chemical conversion of cholesterol (yes, cholesterol).

Some recent information had folks popping Vitamin D3 capsules as they boarded the magic bus to blissful immortality. Like a vampire’s kiss though, the data first reported does not seem to hold up under the direct light of more thorough examination. A more comprehensive study looking at 51 previous trials examined Vitamin D levels and the association between Vitamin D and cardiovascular outcomes, including death. The authors concluded that to date they “are unable to demonstrate a statistically significant reduction in mortality and cardiovascular risk associated with vitamin D. The quality of the available evidence is low to moderate at best.”[1]

However, there are consequences to over consumption. Over indulgence in supplements can result in anorexia, weight loss, excessive urination and heart arrhythmias. It can also cause vascular and tissue calcification, with subsequent damage to the heart, blood vessels, and kidneys. The use of supplements of both calcium (1,000 mg/day) and vitamin D (400 IU) by postmenopausal women was associated with a 17% increase in the risk of kidney stones over 7 years in the Women’s Health Initiative Study.

Eat well and try a little sunlight now and again. Unless of course you actually are a vampire-then I recommend a supplementation of Miss Sooki Stackhouse (see True Blood or the Charlene Harris’ books for those not in the know).


[1] (Elamin, et al., 2011)

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2 responses

26 08 2011
tasteofbeirut

I will pass this on to my daughter who just gave me a lecture on the benefits of Vitamin D.

30 08 2011
What's Cooking with Dr. Mike: The Grassroots Gourmet™

Thanks-have her subscribe to the blog so she gets alll the info!!

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