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Vitamin D May Prevent MS

Dosage Found in Multivitamins Reduces Risk by 40%


Munger's results are encouraging because 20% to 80% of Americans may already be vitamin D deficient -- at least during winter months. While as little as 10 minutes of sun exposure on bare, unprotected skin can prevent deficiencies in warm and sunny months, it's virtually impossible for most Americans to get that kind of exposure this time of year.

Good food sources of vitamin D include:

  • Fortified milk, 8 ounces contain approximately 100 IU of vitamin D
  • Cod liver oil, 1 tablespoon contains approximately 1300 IU of vitamin D
  • Cold-water fish such as salmon and herring, 3 ounces contain approximately 400 to 750 IU of vitamin D respectively.

However, Munger says that no matter where they lived (which could help determine their vitamin D exposure from sunlight), her study's participants who got the highest intake of vitamin D from supplements had the lowest risk of developing MS. Interestingly, those whose vitamin D came only from food, but not pills, had no such decreased risk -- no matter their intake.

Her study is part of the ongoing Nurses' Health Study that has been tracking, for nearly 20 years, how various nutritional and lifestyle habits impact health in some 190,000 women. It's the latest evidence to show that something as simple as taking a multivitamin can offer significant protection against a disease that afflicts some 400,000 Americans. Although the cause of MS is unknown, experts believe it is partly an autoimmune disease that causes lesions within the brain and spinal cord, slowing or blocking nerve signals that control muscle coordination, visual sensation, and other vital functions.

"Very few of the women in our study were taking 'straight' vitamin D supplements," Munger tells WebMD. "Mostly, they got these benefits from a regular multivitamin pill with the standard dosage of vitamin D. While it's too early to conclusively recommend taking multivitamins to prevent MS, certainly many people have advocated taking them for other reasons."

Holick has long recommended that most Americans -- especially those living in cold or gray winter climates -- take a multivitamin and an additional vitamin D supplement of between 400 and 1,000 IU to prevent possible deficiencies. "My guess is that these study participants probably consumed closer to 600 IUs in their multivitamins," he tells WebMD.

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