Saturday, October 17, 2009

Top 10 Myths About Vitamin D

Top 10 Myths About Vitamin D

By Jared M. Skowron, ND

Myth 1: Vitamin D is a vitamin.

Truth: Vitamin D is a hormone. It’s derived from cholesterol. It activates cellular processes and does not do so as a co-factor.

Vitamin D receptors have direct effects on the following cells: adipose, adrenal, bone, brain, breast, cancer, cartilage, colon, endothelium, epididymis, ganglion, hair follicle, intestine, kidney, liver, lung, muscle, osteoblasts, ovary, pancreatic B, parathyroid, parotid, pituitary, placenta, prostate, skin, stomach, testis, thymus, thyroid and uterus.

Myth 2: Normal activity provides us enough vitamin D from average sun exposure.

The truth: Most people do not get enough sunshine to maintain adequate vitamin D levels. Our ancestors spent most of the day in the sun, farming, fishing and hunting. Our bodies physiologically developed to need that much vitamin D. Today’s indoor society of office workers, television watchers and hermits gets much less sun exposure and vitamin D production. Add on clothing and sunscreen, which also inhibit vitamin D production, and you understand the problem.

Myth 3: Supplemented vitamin D in foods is adequate.

The truth: Vitamin D2 is one-third as effective in the body as naturally occurring vitamin D3. Most foods – milk, most notably – have D2 added. A study that analyzed vitamin D2 levels in milk off supermarket shelves showed almost 50 percent had less than the label claim of 400 IU of D2. A support scientist from the USDA believes no food-label claims are accurate and these labels cannot be trusted.

Myth 4: 1,25(OH)D3 is the best analysis for vitamin D levels.

The truth: Vitamin D is mostly stored in adipose and should not be routinely measured. It then converts to 25(OH)D3, which has a long half-life and is the best analysis of vitamin D levels. It then converts to bi-hydroxy forms such as 1,25(OH)D3, 24,25(OH)D3 and other forms, which have the actual action of the cell receptors. However, this form has a short half-life and is not a good measurement.

Myth 5: The reference range for vitamin D levels is accurate.

The truth: The reference range for 25(OH)D3 is horribly inaccurate and is maintaining our vitamin D deficiency in this country. The current reference range of 20-100 is too low. Levels <25>

Myth 6: Vitamin D supplementation is nontoxic.

The truth: The major consequence of vitamin D toxicity is hypercalcemia, which should be monitored periodically while under therapy. Changes in cardiac rhythms or lithiasis are common concerns. Urine calcium monitoring is not accurate. Serum calcium should be monitored monthly to check vitamin D toxicity, which normally occurs at 40,000 IU/day. Right now, 10,000 IU/day is being proposed as the safe upper limit.

Myth 7: The RDA for vitamin D is accurate.

The truth: People taking only the RDA of vitamin D will lower their 25(OH)D3 levels. The RDA is too low. When treating with vitamin D supplementation, three months of daily dosing is sufficient to max out 25(OH)D3 levels. Five thousand IU/day for three months should elevate 25(OH)D3 by 80 nmol/L, and 10,000 IU/day for three months should elevate 25(OH)D3 by 120 nmol/L. People on 1,000 IU/day will elevate their levels by only 10 nmol/L.

Myth 8: Forms of vitamin D are all the same.

The truth: Vitamin D3 is the preferred form. Avoid D2 at all costs. D3 is derived either from plant sources or from lanolin. Lanolin-derived D3 is more active and absorbable. I take the 10,000 IU capsules of D3.

Myth 9: Vitamin D only treats osteoporosis and rickets.

The truth: The therapeutic benefits of vitamin D are still being discovered. Benefits relative to cancer, cardiac, immune-boosting, diabetes and neurological (such as multiple sclerosis) therapies, as well as low bone density, are just the tip of the iceberg. I test all of my patients for vitamin D deficiency and supplement regularly up to the 75-200 reference range of 25(OH)D3.

Myth 10: Vitamin D should be avoided in pregnancy and breastfeeding.

The truth: Pregnant women should receive 4,000 IU of daily vitamin D supplementation. Breast-feeding women should receive 6,000 IU of daily vitamin D supplementation. Vitamin D, not 25(OH)D3, crosses into the breast milk, and daily doses are preferred over weekly doses. Avoid supplementing the infant and instead supplement the breast-feeding mother directly. If the infant is bottle-fed, supplement with 400-800 IU/day.
Dr. Jared M. Skowron is in private practice in Hamden, Conn., where he specializes in pediatrics and treating autistic spectrum disorders in children. He is the senior naturopathic physician with Metabolic Maintenance and an adjunct professor at the University of Bridgeport, teaching pediatrics, CPD and EENT.

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