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REFERENCES:
1. July 2004 American Journal of Epidemiology
2. Poster session abstract: High-dose vitamin E supplementation may increase
all-cause mortality, a dose response meta-analysis of randomized trials;
Ernest N. Morial Convention Center, Exhibit Hall 1-2.)
TO BE PUBLISHED: Annals of Internal Medicine, Nov. 10, 2004
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In some circumstances, it may be. But these are limited conditions and there
are certainly some easy ways to get around them. Let me explain.
I am writing this in response to an article to be published this week in
Annals of Internal Medicine. Researchers at Johns Hopkins have subjected
some Vitamin E studies to a meta-analysis, which is where previously
published studies are re-examined and compared in order to try to mine more
information out of them. These meta-analyses are often highly speculative,
because the protocol for each study is different enough that it becomes a
stretch to link the results and imply a common thread runs through them
despite the different variables. For example, the supplement tested may be
given in different forms or doses, the patient group may have significant
differences, the length of time taking the supplement may vary considerably
or may even include previous users and new users, etc. There are also
differences between natural and synthetic Vitamin E, with most studies using
only the synthetic forms that are composed of different-shaped molecules and
only half as effective as natural Vitamin E. Natural Vitamin E is called
d-alpha tocopherol and synthetic Vitamin E is called dl-alpha tocopherol.
Official U.S. dietary guidelines set an upper tolerable intake limit of up
to 1,500 IU per day, based on the scientific record.
While these meta-analyses are academically useful to point to potential new
problems or solutions, by no means are they definitive proof of anything,
due to the lack of uniform protocols and patient groups. But that won't stop
the medical lobby from trying to use these results to limit potencies of
vitamins to everyone "for our own good". The doctors and researchers may be
well-meaning, but results of this kind of preliminary study can be
publicized and take on a life of their own, with a new role as "proof" of
the dangers of taking vitamins.
One thing that many of the patients in this analysis of previous studies had
in common was being elderly and sick. So the first caution issued by the
report's authors is that their speculative findings would not even apply to
healthy or younger people. That's one BIG argument against using this
analysis to set general restrictions on Vitamin E dosages. We already have
some evidence that taking one antioxidant, rather than antioxidant formulas
or multiple vitamins, may increase the cancer risks for aged smokers. This
may be because antioxidants need to recharge and support each other or else
some can actually transform into pro-oxidants that can increase the damage.
I always caution against taking mega-doses of one nutrient without
considering potential side effects. Taking only one antioxidant may seem to
deplete others because of the way they interact, with one antioxidant
chemically supporting others. A surplus of one nutrient may increase a
person's need for one or more other nutrients, creating an apparent
functional deficiency.
There is a recent example that illustrates my point. Some years ago an
antioxidant study in Finland was halted early, with a widely reported
increase in cancer rates among male smokers taking beta-carotene. Headlines
associated vitamins with cancer risk. Despite objections that the study was
flawed, vitamin use dropped.
Fast-forward to this year. A new analysis published in July takes another
look at that same Finnish smokers' study, but now takes into account their
total antioxidant intake, and clears up that whole controversy. Their risk
of getting lung cancer was closely associated with total antioxidants in the
diet, with more antioxidants meaning less cancer.
A composite antioxidant index was generated for each of the 27,000 men over
14 years. The calculated amounts of carotenoids, flavonoids, Vitamin E,
selenium and Vitamin C were compared to actual lung cancer rates, with a
clear result: a combination of antioxidants lowers lung cancer risk in male
smokers.
What does this all mean? I think we are in for another round of attacks on
vitamins based on this crude analysis of Vitamin E, with some medical
experts calling for restrictions on vitamin potency. That would be a
mistake, both scientifically and from a public health viewpoint. The message
should be that people should not try to take a high dose of one supplement
without considering that it may increase our need for other nutrients.
Elderly, sick people need a more holistic approach rather than using a
single nutrient in high doses, as if it were a drug. Nutrients just don't
work well in isolation from each other. Vitamins are essential to health and
life, but the average American gets only 1/3 of the recommended daily intake
of Vitamin E that would prevent serious illnesses. Most people would benefit
from taking a multiple vitamin and a Vitamin E supplement, and it would be
safer than just the Vitamin E alone.
That shouldn't be hard for the smart folks at Johns Hopkins to understand.
By Neil E. Levin, CCN, DANLA
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