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Search Health Information    How Many Vitamins is Too Many Vitamins?
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Health News Feature
Weekly news feature articles on current health topics that affect you and your family.


How Many Vitamins is Too Many Vitamins?


How Many Vitamins is Too Many Vitamins?(HealthDay News) The wisdom of Aristotle in ancient Greece preaches moderation in all things. The demands of the Roman rulers like Nero were that too much was not enough.

In the world of wellness, is one of these philosophies the right one? Science is only now starting to find answers to determine how much of anything taken to keep you healthy is too much. For example, mainstream medicine has given antioxidant megavitamins some major tryouts. So far, the vitamins have failed in the key studies.

Only recently the good thing about loading up on, say, the antioxidant vitamin E was that even if this approach to improved health didn't work, it certainly wouldn't backfire. Like chicken soup, it couldn't hurt. And many noted scientists and clinicians privately were believers.

Antioxidant-vitamin supplements took a licking in 2004. It's probably fair to say that one should question whether it's good to over-expand the way Mother Nature goes about her business. A good thing—vitamins in the diet—taken to extreme with mega supplements may equal a bad thing.

A Johns Hopkins study of vitamin E published in November 2004, suggested that a daily dose of 400 IUs (international units) or more was linked to a 6 percent increased risk of death. In the analysis of 136,000 patients, the risk of death starts to increase at 150 IU, but at 400 IU, the risk of dying from any cause rises about 10 percent.

"People take significant amounts of vitamin E because they have a perception that it will provide some health benefit, and that this will help them live longer, but just the opposite could be the case," said Dr. Edgar R. Miller, an associate professor of medicine, who was the study author. There is no recommended dose for vitamin E, although guidelines set a tolerable limit of up to 1,500 IUs per day. Daily intake of vitamin E through foods is 10 IUs, and multivitamin pills usually contain 30 to 60 IUs of vitamin E. So, 400 IUs is a lot.

But it was just another blow to the once-popular concept that extra doses of the antioxidant vitamins—E, C, and beta carotene (a plant pigment called a carotenoid that the body converts into vitamin A)—would beef up the body's chemical reactions to dangerous free radicals, with health-promoting effects such as preventing lung cancer or heart disease for ex-smokers.

The Hopkins vitamin E study was a re-analysis of the data from 19 vitamin E studies over the past decade. The vitamin-supplement industry immediately attacked the study's methodology. And the study may not stop dedicated believers from taking high doses of vitamin E, much to the chagrin of physicians who have trouble getting patients to take agents with documented efficacy.

And beta carotene? Previously, high doses of beta carotene had been shown to increase the risk for lung cancer and death compared with the risk to those in the controlled trial who got a placebo.

Late in the year, beta carotene got more bad news, at least for women. Six years after a study was halted early because the risky effects of high-dose beta carotene to heart disease and cancer were detected, follow-ups showed that for women, the bad effects lingered. The participants took 30 milligrams a day, about 10 times the amount in a daily multivitamin supplement, combined with 25,000 IUs of retinyl palmitate, a drug also thought to be a cancer fighter.

The study organizers found that the increased risk of heart disease and cancer disappeared when the men in the study, all former smokers or those with asbestos exposure, stopped taking the beta carotene supplements. But for women it didn't work. Before the study was halted, the participants who took the supplement had a 28 percent greater incidence of lung cancer and 17 percent more deaths from all causes compared with those who didn't take the beta carotene. In the follow-up, women were 30 percent more likely to develop lung cancer, 40 percent more likely to die of heart disease, and 30 percent more likely to die of all other causes.

This may be because beta carotene and vitamin E are both fat-soluble, allowing any excess to accumulate in fat-cell membranes. This could explain the adverse effects of beta carotene in women, who have more body fat than men. Vitamin C is water-soluble and any excess leaves the body via urine.

High-doses of vitamin C, while not fulfilling the claims of its advocates, have not been shown to be dangerous, although the noted hematologist and strident critic of fad diets, the late Dr. Victor Herbert of the Bronx Veterans Administration, attempted to link supplements of iron or vitamin C, or both, to iron-balance pathology.

Dr. Herbert was irked by Linus Pauling, the legendary Nobel Prize-winner in chemistry, who was a tireless promoter of the purported benefit of vitamin C in preventing the common cold, a claim undocumented but claimed as gospel by many. Albert Szent-Gyorgyi, who won the Nobel Prize in medicine for his work on vitamin C, touted the vitamin's ostensibly unrecognized healing properties, including effects against cancer.

Pauling and Szent-Gyorgyi claimed to be visionaries in a blind world. Herbert and his supporters saw themselves as voices of sanity in a health-food dominated society.

More information

To learn more about beta carotene, visit the National Library of Medicine.

The National Institutes of Health offers a fact sheet on vitamin E.


SOURCES:
Author: Mark Bloom, HealthDay Reporter
Mark D. Thornquist, Ph.D., biostatistician, Fred Hutchinson Cancer Research Center, Seattle; Anna Duffield-Lillico, Ph.D., assistant attending epidemiologist, Memorial Sloan-Kettering Cancer Center, New York City; Dec. 1, 2004, Journal of the National Cancer Institute; Edgar R. Miller, M.D., Ph.D., associate professor, medicine, Johns Hopkins University, Baltimore; Dean Jones, Ph.D., professor, medicine, Emory University School of Medicine, Atlanta; Nov. 10, 2004, Annals of Internal Medicine; Nov. 10, 2004, presentation, American Heart Association's scientific sessions, New Orleans; statement by the Council for Responsible Nutrition, Washington, D.C.
Publication date: January 1, 2005
Copyright © 2005 ScoutNews LLC. All rights reserved.

 


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