Recently, a now-famous beta carotene-cancer study from Finland hit the front pages of many newspapers and magazines. The newspaper articles warned that beta carotene might cause cancer and that people should not be so willing to take nutritional supplements because they may be dangerous. These newspaper reports and magazine articles were based on a study published in the prestigious New England Journal of Medicine on April 14, 1994. The study was entitled “The Effect of Vitamin E and Beta Carotene on the Incidence of Lung Cancer and Other Cancers in Male Smokers.” Although carried out in Finland, the study was co-sponsored by the National Cancer Institute and paid for largely with your tax dollars.
In this study, more than 29,000 middle-aged men, who smoked over a pack a day for an average of 36 years each, were divided into four groups and followed for five to eight years. One group received daily dosages of 20mg (or 33,000 units) of synthetic beta carotene. A second group received 50mg of synthetic vitamin E, in the form of dl-alpha tocopherol acetate. A third group received both of these supplements. And, finally, a fourth group received a placebo.
The results of the study indicated a significant 18% increase in incidence of lung cancer in the participants receiving beta carotene. Although, fewer cases of prostate cancer were diagnosed among those who received vitamin E than those who did not, this point was not emphasized in the news accounts.
What were the flaws in the study? There were many. The study used only 1/8th to 1/40th the dosage of Vitamin E shown by more than 20 previous studies to lower the risk of lung cancer in smokers. It used only 1/10th the dosage of beta-carotene recommended by other experts for the prevention of lung cancer in smokers. It used as subjects people from Finland despite the fact that both the British Medical Journal and the American Journal of Clinical Nutrition consider Finland one of the worst countries in the world for cancer/nutrition studies since: (1) Finns have one of the world’s highest rates of per capita alcohol consumption by smokers, and alcohol interferes with the utilization of Vitamin E and beta carotene, and (2) Finland has an extremely low level of the essential mineral selenium in the soil, and selenium works together with vitamin E in promoting cancer prevention.
A previous, much less publicized recent study, carried out in China with National Cancer Institute cooperation, included 50 micrograms of selenium, along with 30 mg of vitamin E and 15mg of beta carotene. This study involved 30,000 people over the age of 40, who were either healthy or suffered from the premalignant lesion, esophageal dysplasia. Those who received the combination of these three nutrients had a significantly lower risk of dying from cancer and other diseases.
Other criticisms of the study include the fact that the study started immediately after the Chernobyl nuclear disaster, which occurred in 1986, and Finland was one of the first areas to receive heavy fallout. This variable increases cancer risk and makes the jobs of these low levels of antioxidants more difficult. The form of vitamin E was the less potent synthetic dl-alpha tocopherol rather than the physiologic d-alpha tocopherol form. And all of the supplements were colored with quiniline yellow, a substance with known carcinogenic properties.
The authors themselves were careful to point out that no other studies have ever shown any harm from taking beta carotene, whereas many studies have shown beneficial effects. In addition, there are no known mechanisms for toxic effects of beta carotene. There overall conclusion was: “In spite of its formal statistical significance, therefore, this finding may well be due to chance.”
You would never know this from the media circus accounts of the study. The universal message, received by many of my patients and the general population, was that vitamins, particularly beta carotene, cause cancer. I hope that this information clears up some of the confusion.