Tag: Cochrane

A Dangerous Cocktail

Claus Hancke

October 3, 2004

Politicizing researchers and lazy journalists are a dangerous cocktail.
It is very disgraceful that the Danish Radio’s TV news presented such a one-sided story about antioxidants, as happened at 6:30 p.m. yesterday, where it declared without any reservation that 9 people out of 1,000 taking antioxidants will die from them!

Just the day before, the Danish (state owned) Radio / Television received a press release from the Vitality Council, which was criticizing the story and emphasized that possible harmful effects can only be caused by taking beta-carotene in large (therapeutic) dosages.

This old news can in no way be used to generalize about other antioxidants. The postulated general overmortality refers to two studies, in which beta-carotene was used in such great amounts that the test persons became yellow.

The Vitality Council also emphasized in its press release that according to the Lancet study, selenium, a potent antioxidant, is able to halve the risk of several kinds of cancer. This result was not at all mentioned in the TV news.

Furthermore, even the official comment in The Lancet dissociated from that which was the only extract on TV from the study: The postulated overmortality. The Lancet comment is written by two statisticians, who are seriously criticizing the statistical preparation of the material, and they state that the conclusion about overmortality is not convincing.

Another critical point out of many is that the Cochrane group removed a study on selenium, which it had announced as being a ”high quality” study, before the calculation on average.

The reason given for removing the study was that it would be given more weight in the random-effects model than in the fixed-effect meta-analysis. The removed high-quality study showed that selenium clearly reduced mortality!

It is not very good science to ignore figures that you do not like.

The TV news journalists have been hunting for some sort of scandal and one-sidedly accepted the very dramatic statements of Christian Gluud, M.D., which went much further than what the study material could ever support.

The Lancet has saved its skin by its serious comment, but the writers have cast a bad shadow over the Cochrane institution.

By: Vitality Council

References:
1. TVA 2.nd October 2004, 6:30.
2. Press release from Vitality Council 1.st October 2004.
3. Goran Bjelakovic, Dimitrinka Nikolova, Rosa G Simonetti, Christian Gluud, Antioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis, Lancet 2004;364:1219-28.

www.lancet.com
www.cochrane.dk/index.htm
www.iom.dk

Not All Antioxidants Prevent Cancer

Claus Hancke

October 1, 2004

The Cochrane Institution is very well-respected for its objective consideration of medical issues. The last report from The Lancet today does not actually reveal anything truly new, despite a very useful summary of results from earlier prevention studies made with antioxidants. The results are listed after each antioxidant and after each type of cancer in the gastrointestinal tract.

The good news is that it looks as if selenium may very effectively prevent cancer diseases in the gastrointestinal region, as selenium both halves the frequency of cancer as well as the rate of death in the group of people taking selenium compared with the group taking placebo.

The disappointing news is that certain other antioxidants do not have any cancer-preventive effect in the studies mentioned and in some cases they even have harmful effects – mainly attributed to beta-carotene. This is a well-known fact.

The authors are inclined to think that the ones who might be harmed by antioxidants are people who are not very strained by the harmful free radicals in the first place. However, the authors will not warn against taking moderate doses of antioxidants or eating fruits and vegetables, and they thereby recognize the importance of getting moderate amounts of these antioxidants.

The study should be a memento for the authorities who prevent the public from being informed with fair and useful information on effects as well as side effects of dietary supplements. This censorship conceals positive as well as negative research results to the consumer who is left only to pure speculation about the use and dosage of the antioxidants which could be very beneficial if used correctly.

Antioxidants prevent atherosclerosis with great probability, but, naturally, this must happen before the atherosclerosis is far advanced. Based on his own research, the Californian Nobel Prize Winner Louis Ignarro, one of the world’s leading experts in vascular surgery, has recently in very clear terms encouraged anyone who want to avoid having blood clots to take supplements of vitamin C and -E.

In the last three months alone, the Vitality Council have posted at least six press releases about new scientific research regarding antioxidants; all involving important – in some cases essential – new knowledge from the leading research centres around the world.

By: Vitality Council

Reference:
Goran Bjelakovic, Dimitrinka Nikolova, Rosa G Simonetti, Christian Gluud Antioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis Lancet 2004; 364: 1219-28.

www.lancet.com
www.cochrane.dk/index.htm
www.iom.dk

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Biased Cochrane Study – 07-10-04 12:00
A Dangerous Cocktail – 03-10-04 12:00