VITAMINS AREN'T "FINNISH-ED":
DID CAROTENE STUDY SHOW
SUPPLEMENTS CAUSE CANCER?
From The Cancer Chronicles #21
© May 1994 by Ralph W. Moss, Ph.D.
Did you hear about the recent study in which beta carotene (vitamin A) dramatically decreased one's risk of dying from cancer? No? Then how about the one in which Finnish smokers who took beta carotene had more lung cancer. Of course.
You¹d have to be living in a yurt not to have had that news beamed into your living room. It made the front page of the New York Times ("Vitamin Supplements Are Seen as No Guard Against Disease," 4/14/94) and, in an unprecedented move, ABC broke a news embargo imposed by the New England Journal of Medicine, to scoop the story as lead item for its "Evening News."
Both studies were reported by National Cancer Institute scientists. Both were cooperative ventures, involving large numbers of foreign subjects, published in leading U.S. journals. But there the similarities ended.
The first study was on Chinese residents of Linxian county. Although published last September (JNCI 1993;85:1483-1492), it was re-released by NCI at a scientific meeting on 4/11/94. This Chinese-U.S. study found that ³nutrient supplements reduced the risk of dying from cancer and other diseases for healthy people and those with esophageal dysplasia² (a precancerous condition common in China).
In a study of nearly 30,000 adults over the age of 40, those who got a combination of beta carotene (15 mg), vitamin E (30 mg of alpha tocopherol), and selenium (50 micrograms) had "a 13 percent decreased risk of dying from cancer and a 9 percent decreased risk of death from all causes." Those in the dysplasia study had an 8 percent lower risk of dying from esophageal cancer and a 38 percent lower risk of death from stroke. These results are consistent with about 200 other published studies on similar benefits from vitamins.
"This is a hopeful sign that vitamins and minerals may help prevent the onset of cancer in healthy individuals," said Dr. William J. Blot of the NCI.
On the other hand, the Finnish study (NEJM 1994; 330:1029-1035) was conducted on a different, and far less promising, population. These were 29,000 middle-aged men (57.2 years) who smoked over a pack a day and had done so for an average of 35.9 years each. There was an 18 percent greater incidence of lung cancer among those receiving the beta carotene in this study group.
This is what created the media circus. But several important factors went unnoticed in both the paper and in media reports. For example, the Finnish diet is high in animal fat, and alcoholism is a major problem there. These are well-known carcinogenic co-factors.
In addition, the study started immediately after the Chernobyl nuclear disaster, which occurred in 1986. "Finland was one of the first areas to receive heavy fallout," according to Marjorie A. Laughlin, MD, in a letter to the Times (4/28/94). This fact, she points out, was not mentioned in the Times nor in the NCI paper itself.
In addition, the Finnish men were given 20 mg per day of "synthetic beta caroteneŠcolored with quiniline yellow." Why synthetic vitamins? And why quiniline yellow, a substance with known carcinogenic properties, asks Michael A. Weiner of the Chicago Medical School. Such yellow-dyed synthetic supplements "are not to be compared with undyed supplements," he writes (ibid.).
At the same time, there was an unheralded reduction in prostate and colorectal cancer as well as a small reduction in lung cancer in the vitamin E group.
The authors themselves were careful to point out that no other studies have shown any harm from taking beta carotene, whereas many studies have shown benefit. There are also no known mechanisms for toxic effect, and "no evidence of serious toxic effects of this substance in humans."
Their overall conclusion was: "In spite of its formal statistical significance, therefore, this finding may well be due to chance."
You would never know that from the media accounts. "Vitamins Cause Cancer" was universally the takeaway message. Although the study is on-going, the timing was suspicious"³at the height of a heated debate over vitamins and supplements as the subject of numerous bills in Congress," according to Dr. Laughlin. But the quackbusters had their day, and the effect was predictable:
Readers should know that the case for supplementation with high-quality, undyed, natural antioxidants remains strong. However, everyone should also be aware that supplements are just that--things to be added to a healthy diet and life style, not substitutes for them.
As a side note, scientists at S.M.U. increased the life span of fruit flies by one-third by enhancing their utilization of vitamins. "That¹s why some people believe that antioxidants such as Vitamins C and E, which inhibit that damage," says Science (2/25/94) "may retard the breakdown of various bodily systems." The scientists called their experiment "the first direct support for the free radical theory of aging."
Sure. But is anybody listening?
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