November 12, 2004
Calculations on the basis of old studies leads to claim of increased mortality by antioxidants and vitamin E, but is in reality based on studies with beta-carotene.
Recently, researchers published a study on beta-carotene, but called it antioxidants. Now there is a new study of beta carotene, but this time it is called vitamin E. Both studies are so-called meta-analyzes, ie. calculations of previous research.
The two studies claim to show that respectively antioxidants and vitamin E increase mortality, but they are both based on the results of old beta-carotene tests. Since 1994, it has been known that beta-carotene can cause cancer and increase mortality in at least male smokers.
The latest meta-analysis originates from Johns Hopkins University in the USA. Here, the mortality rate in a total of 19 old treatment trials with vitamin E was investigated. Apparently, doses above 400 units per day slightly increased mortality, although it was decreased in the trial where the dose was the highest (2,000 units/day). There were 11 trials where more than 400 units were used per day. At a lower dose, there was a tendency for decreased mortality.
However, of the 11 trials, the so-called Heart Protection Study (HPS) from the year 2000 is by far the largest. In fact, so large that it completely dominates the calculation. In HPS, almost twice as many died as in all the other 10 trials combined – and more than four times as many as in the other trials with increased mortality. The problem with this is that in HPS, in addition to vitamin E, the treatment consisted of vitamin C and beta-carotene!
Of course, one cannot comment on the risk of vitamin E based on an experiment in which both vitamin E and C and beta-carotene were used. You can only comment on vitamin E and C and beta-carotene!
Also, in the trial in question (HPS), synthetic vitamin E was used. It consists of eight different chemical compounds, only one of which is found in nature. That makes it even more difficult to comment on vitamin E, which most people buy in its natural form.
There are many other objections to the new meta-analysis. If you e.g. arrange the numbers just a little differently, but still fairly, the excess mortality disappears entirely. That happens if you ignore the misleading HPS study and include trials using over 300 units instead of just over 400. That would be entirely plausible.
This and much else may be why several independent statisticians told the New York Times that they did not believe the conclusion.
One can debate whether there is a real need for these sometimes arbitrary concoctions of old experiments, which easily lead to misinterpretations. Far greater is the need for large-scale investigations into whether, for example, a combination of natural vitamin E and C prevents atherosclerosis in people who are not overwhelmingly atherosclerosis already. This is where one can expect an effect, but these experiments have not been carried out.
Sales of vitamin E are increasing in the United States, where many doctors in particular take it. The combination of vitamin E and C can be seen i.a. as a competitor to the tremendous expensive, but almost ineffective, prescription drugs for Alzheimer’s. According to a report earlier this year – also from Johns Hopkins – users of both of these vitamins have approx. 80% reduced risk of getting Alzheimer’s – compared to those who get only one of them or none at all.
Most recently, the Nobel laureate Louis Ignarro, based on his own experiments, strongly recommended the same combination as prevention against atherosclerosis.
By: Vitality Council
1) Metaanalysis: High-dosage vitamin E supplementation may increase all-cause mortality. Ann Int Med 2004;142.
2) Bjelakowic G, Nikolova D, Simonetti R G, Gluud C. Antioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis. The Lancet 2004;364:1219-28.
3) Ignarro L J et al. “Long Term Beneficial Effects of Physical Training and Metabolic Treatment on Atherosclerosis in Hypercholesterolemic Mice. PNAS 2004 (May 24).
4) Zandi PP et al. Reduced risk of Alzheimer disaease in users of antioxidant vitamin supplements. Arch Neurol 2004;61:82-88.
5) Gina Kolata: Large Doses of Vitamin E May Be Harmful. New York Times 11.11.04.