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Simple Facts about Vitamin D

by Dr. Randy

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Vitamin D has been in the news over the past year. The American Academy of Pediatrics announced that all breastfed babies should take a vitamin D supplement to prevent rickets. Protests immediately arose from breastfeeding proponents who questioned the motives behind this denigration of breastmilk’s adequacy as a complete food for babies. They also questioned the wisdom of universal supplementation for babies without adequate studies on possible adverse effects. Although vitamin D deficiency is most often associated with osteoporosis and poor bone development, many other health conditions have also been linked to low vitamin D levels. Two studies published in January 2004 showed that vitamin D intake significantly reduces the incidence of autoimmune disease. In one study, women who took 400 IU or more of vitamin D per day were 40 percent less likely to develop multiple sclerosis compared to women who used no D supplement (Munger, 2004). A second study showed 33 percent reduction in rheumatoid arthritis incidence for women who took a vitamin D supplement (Merlino, 2004). Breast cancer, prostate cancer, skin cancer, depression, diabetes, and heart disease have all been associated with vitamin D deficiency. And according to many authorities vitamin D deficiency is all too common in North America and Europe.

Our bodies produce vitamin D in response to sunlight (UVB radiation), but areas of the world north of latitude 30 north, San Diego (USA) or Cairo (Egypt), may not get enough sun during September through May to provide adequate vitamin D levels. The current recommendation for adult intake of vitamin D is 400 IU per day, but findings from a study published in the Journal of Internal Medicine suggested that a vitamin D intake of 600 IU was insufficient to maintain adequate vitamin D levels in the body in the absence of sun exposure. They proposed an increase of the minimum daily recommended adult dose to 1,000 IU per day (Glerup, 2000).

Vitamin D, however, can be toxic. Therein lies the problem. We cannot get too much vitamin D from the sun, but we can from supplemental sources.

Babies

Babies’ vitamin D stores at birth can be increased if their mothers have had adequate exposure to sunlight and/or adequate vitamin D intake during their pregnancies. Vitamin D is essential for bone growth in infancy and throughout childhood. The two reliable and safe sources of vitamin D for babies are sunlight and cod liver oil.

According to Barber and Purnell-O’Neal writing in Mothering Magazine, “a baby in a diaper needs a total of only 30 minutes of sunlight a week – less than five minutes a day. Fully clothed and without a hat, a baby would need two hours of sunlight a week, or about 20 minutes a day. Medium to darker skin tones need a little more time in the sun (Barber & Purnell-O’Neal, 2003).”

Avoid prolonged exposure to bright sunlight because of the danger of sunburn. Babies will get enough vitamin D if they have access to a bit of sun each day.

Babies that reside in North America and Europe may need vitamin D supplementation during the colder months of the year when sun exposure is not possible and weather prevents adequate exposure to the healthy rays of the sun.

The usual daily dosage of vitamin D3 for babies is 800-1,000 IU and 2,000 IU for toddlers and older children.

Adults

It is safe to obtain vitamin D from the sun’s UVB radiation or from foods. Vitamin D3 (cholecalciferol) is found in eggs, animal fat, and cod liver oil. Do not eat fish to secure vitamin D in your diet. The fish available to us is not safe to eat. Vitamin D2 (ergocalciferol) found in plants is less biologically active and is toxic at high dose levels, above 10,000 units per day.

Have your vitamin D levels tested before supplementing your diet. The correct test is 25-hydroxyvitamin D. Normal values, according to Dr. Joseph Mercola, are 60-85 ng/ml . Most lab reference ranges are too low.

Do not attempt to supplement your diet with significant amounts of vitamin D without adequate testing. Krispin Sullivan, author of the forthcoming vitamin D book Naked at Noon recommends frequent testing. “Minimum testing should not be less than every three months the first year and six months the second and third years. Elevated 25(OH)D may not show up in a blood test until as long as 2-3 years after starting an excessive dose” (www.sunlightandvitamind.com).

The typical vitamin D dosage is 5,00-10,000 IU for a 150 pound person. Sullivan recommends seeking out a health care provider knowledgeable in vitamin D supplementation. Use cod liver oil during the winter months and switch to a fish oil omega-3 supplement during months when exposed to sunshine is possible.

Do not use a daily sunscreen. Reserve sunscreen use for the prevention of sunburn during midday exposure in bright sunlight, when swimming, at the beach, and during snow sports. Then use only zinc oxide sunscreens (UV Natural, Soleo Organic).

Summary

Babies’ dosage of vitamin D: Sun exposure of 20 minutes per day. When that is not possible, give 800-1,000 IU.

Adults’ protocol for vitamin D evaluation and supplementation: Daily sun exposure when possible. Test 25(OH)D levels. Supplement with 5,000-10,000 IU and retest.

References:

Barber, K, and Purnell-O’Neal, M. The politics of vitamin D: Questioning universal supplementation. Mothering Magazine, Issue 117, March/April 2003

http://www.mothering.com/12-0-0/html/12-1-0/vitamin-d.shtml

Glerup, H, et al. Commonly recommended daily intake of vitamin D is not sufficient if sunlight exposure is limited. Journal of Internal Medicine 2000, 247(2): 260-8.

Mercola, J. Test values and treatment for vitamin D deficiency

http://www.mercola.com/2002/feb/23/vitamin_d_deficiency.htm

Merlino, LA, et al. Vitamin D intake is inversely associated with rheumatoid arthritis: Results from the Iowa Women’s Health Study. Arthritis & Rheumatism 2004, 50(1): 72-77.

Munger, KL, et al. Vitamin D intake and incidence of multiple sclerosis. Neurology 2004, 62(1): 60-65.

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