An article in this week’s New England Journal of Medicine charges that the government’s current recommendations for vitamin D intake are woefully inadequate. The author, Dr. Michel Holick, claims that the current guidelines, which recommend 200 IU per day, are not enough to prevent vitamin D deficiency in most people. Dr. Holick would like to see the RDA increased to 800-1,000 IU per day.
Without enough vitamin D, your body absorbs only a fraction of the calcium you take in. According to Dr. Holick, the absorption of calcium can be as low as 15% in the absence of vitamin D. The most serious consequence of vitamin D deficiency is an increased risk of osteoporosis (in adults) and skeletal deformaties (in children). It can also cause muscle weakness and immune defiencies.
Vitamin D is not very widespread in the food supply. Oily fish like sardines and herring are good natural sources. But most Americans get the lion’s share of their dietary vitamin D from vitamin supplements or fortified foods. (Milk, for example, is often fortified with vitamin D.) Keep in mind, though, that the amount of vitamin D in vitamin supplements and fortified foods is based on the current RDA of 200 IU–so even if you faithfully swallow a multi-vitamin every day, you may be coming up short.
The Sunshine Vitamin
The other chief source of vitamin D is not dietary but environmental. Your body can manufacture its own supply of vitamin D if you expose your unprotected skin to the sun’s rays. Experts estimate that a daily 15-minute sunbath at mid-day (with the sun hitting your arms, face and neck, for example) would be enough to top off your vitamin D stores. But these days, most of us are trying to mimize our sun exposure to prevent skin damage, and wearing sunscreen blocks the vitamin D-making process. And even without sunscreen, those who live further from the equator (such as in the Northern United States and Europe) will have trouble getting enough sun exposure to ward off deficiency in the winter.
How much vitamin D are you getting?
Are you even getting the current (and, some say, inadequate) RDA of vitamin D on a daily basis? Use NutritionData’s total consumption report to analyze a typical day’s diet and see. Don’t forget to add in any supplements you may be taking. (You can add those to your pantry as a custom food.)
Convinced that the current recommendation is too low? You don’t have to wait for the government to change the RDA for vitamin D–those wheels turn awfully slowly! You can set your own daily target for vitamin D or any other nutrient using the preferences setting on NutritionData. Read this post to learn how.
Source / NutritionData / Posted July 24, 2008
Thanks to Janet Gilles / The Rag Blog