Supplements of vitamin D and calcium, taken together over four years, may significantly reduce overall cancer risk.

That’s the conclusion of a study that followed 1,180 healthy post-menopausal women over the age of 55. When I told you about that study in the e-Alert “Flying Lessons” (7/24/07), I noted that Dr. Michael Holick now recommends a daily vitamin D3 intake of 800 to 1,000 IU. Dr. Holick was a member of the panel that set the 1997 guidelines for daily vitamin D intake at 200 to 600 IU daily, depending on age.

Obviously, Dr. Holick has uncovered some impressive new information about vitamin D over the past 10 years, and he shares that information in a recent issue of the New England Journal of Medicine.

Here are some key points from Dr. Holick’s paper:

As many as one billion people may be vitamin D deficient

Europeans are especially vulnerable to deficiency – especially those in the north who are exposed to lower levels of UVB radiation (the component of sunlight that prompts the manufacture of vitamin D in the skin)

Without adequate vitamin D intake, dietary calcium and phosphorus are very poorly absorbed, undermining bone and muscle health

For most people who live far north or south of the equator, adequate levels of vitamin D3 (the type of vitamin D produced by UVB radiation exposure) can only be obtained with frequent intake of oily fish and/or supplements

As I noted in the “Flying Lessons” e-Alert, 1,000 IU of vitamin D daily may actually be a low target. Dr. Jonathan V. Wright, M.D., recommends 1,600 and 2,000 IU of vitamin D daily, and as much as 4,000 IU for those over the age of 40. Cod liver oil provides more than 1,300 IU of D per tablespoon.

Talk to your doctor before increasing your vitamin D intake.

Sources: “Vitamin D Deficiency” New England Journal of Medicine, Vol. 357, No. 3, 7/19/07, content.nejm.org