Vitamin E linked to increased lung cancer risk

A second popular vitamin supplement has been found to heighten the likelihood of developing lung cancer, it was disclosed today.

Findings from a study of more than 77,000 people showed that taking moderate to high doses of vitamin E led to a “slight but significant” increase in risk.

Previous research had already linked beta-carotene supplements with a higher risk of lung cancer in smokers. The vitamin E trend was most prominent among smokers, but not confined to them.

The researchers also found no evidence that multivitamins or vitamin C reduced the risk of lung cancer.

A team led by Dr Christopher Slatore, from the University of Washington in Seattle, in the United States, monitored 77,126 men and women between the ages of 50 and 76 for four years, recording how many of them developed lung cancer.

Of the original participants enrolled into the Vitamins and Lifestyle (Vital) study, 521 were diagnosed with the disease – the expected rate for a low-risk group of patients.

The scientists found unsurprising links between lung cancer risk and smoking, family history, and age. But in addition to these, they uncovered the unexpected association with vitamin E.

The increased risk was equivalent to 7% rise for every extra 100 milligrams of vitamin E taken per day over 10 years. This translated into a 28% increased risk of lung cancer for someone regularly taking a high 400 milligram dose of the vitamin.

“In contrast to the often assumed benefits or at least lack of harm, supplemental vitamin E was associated with a small increased risk of lung cancer,” said Dr Slatore.

The findings appear in the March issue of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.

Six years ago a scare over beta-carotene and lung cancer prompted calls for health warnings for smokers to be placed on bottles of vitamin supplements.

A Finnish study of 29,000 male smokers published in the New England Journal of Medicine showed that participants were 18% more likely to develop lung cancer if they took beta-carotene, which is converted into vitamin A in the body.

Other research from the US found a 28% increase in lung cancer risk for asbestos workers and smokers given the supplement.

In 2004 scientists from Johns Hopkins University in Baltimore, US, presented findings showing an increased risk of all-cause death among elderly people taking moderately high doses of vitamin E.

The new research adds to the growing evidence that vitamin supplements are a poor substitute for a healthy diet rich in fruit and vegetables.

In an accompanying article in the American Journal Respiratory and Critical Care Medicine, Dr Tim Byers, from the University of Colorado, wrote: “Fruits contain not only vitamins but also many hundreds of other phytochemical compounds whose functions are not well understood.”

Dr Slatore added: “Future studies may focus on other components of fruits and vegetables that may explain the decreased risk (of cancer) that has been associated with fruit and vegetables.

“Meanwhile, our results should prompt clinicians to counsel patients that these supplements are unlikely to reduce the risk of lung cancer and may be detrimental.”