What's your opinion of the recent AHA study on vitamin C

[Guest guest]

Today's Question

What's your opinion of the recent study which says vitamin C (taken

in pill form) can harden or clog arteries? Do you have any

suggestions on how to get vitamin C while avoiding the negative

consequences that showed up in the study?

 

-- Bill

 

Today's Answer

(Published 05/16/2000)

Updated 12/6/2001

The results you mention were presented at an American Heart

Association meeting in March. Researchers from the University of

Southern California at Los Angeles examined artery ultrasounds of

573 middle-aged men and women. Those who took 500 milligrams of

vitamin C daily, for at least a year, had blood vessels that

thickened two-and-a-half times faster than those who didn't take

supplements. The rate of thickening was even higher among smokers.

 

Frankly, I don't find these results credible. When they announced

their findings, even the scientists who conducted the study said

that more research is needed to confirm -- or refute -- this data.

Bear in mind that the study in question was unpublished, and the

results were inconsistent with everything we know about vitamin C.

 

I would rather focus on some of the good news about vitamin C:

 

The March 2000 issue of the " Journal of the American Academy of

Neurology " reported that supplementing diets with vitamins C and E

may boost mental ability in later life -- and could protect against

some forms of dementia, including the vascular dementia that can

occur as a result of a stroke. The study involved 3,385 Japanese-

American men aged 71 to 93. Those who took vitamin E and C

supplements regularly (at least once a week) were 88 percent less

likely to have vascular dementia four years later -- and 69 percent

less likely to have other forms of dementia. However, the study

found no overall protection against Alzheimer's disease.

 

Another study involving more than 13,000 men and women, found that

women who took vitamin C supplements were less likely to develop

gallbladder disease. Results were published in the April 2000 issue

of the " Archives of Internal Medicine. "

 

And in the March 2000 issue of the " Journal of Family Practice, "

researchers reported that vitamin C may help prevent a type of nerve

pain (reflex sympathetic dystrophy) that can develop after an

injury.

 

You may have noticed that the Food and Nutrition Board of the

National Academy of Sciences, the outfit that sets the Recommended

Dietary Allowances (RDAs), recently raised the RDA for vitamin C

from 60 mg to 75 mg daily for women, and 90 mg daily for men. I

still think this is too low and stand by my recommendation for

healthy adults of 200 to 500 mg daily, divided into two doses. In

the past, I recommended much higher doses (2,000 to 6,000 mg divided

into three doses daily) but changed my thinking after reviewing

research which showed lower doses are probably effective in helping

to reduce the risk of cardiovascular disease, cancer, cataracts, and

other chronic conditions. Occasionally I recommend slightly higher

doses for individuals with specific health conditions such as

macular degeneration, high blood pressure and exposure to second-

hand smoke.

 

Andrew Weil, M.D.

www.drweil.com