Lung cancer: the adverse effect of two dietary supplements persists after stopping consumption

The side effects of beta-carotene and retinyl palmitate (vitamin A) on the incidence of lung cancer and all-cause mortality in smokers and people exposed to asbestos persist several years after discontinuation these dietary supplements, warn the authors of a study.

A study was conducted by an American team to assess the effect of a daily intake of beta carotene (30 mg) and retinyl palmitate (25,000 IU) on the incidence of lung cancer, other cancers and mortality among 18,314 people at high risk of lung cancer because of a history of smoking or exposure to asbestos.

The test, called CARET, had to be discontinued in 1996 because of the risks incurred by participants receiving both food supplements, the risk of lung cancer was increased by 28%, that of death by 17% and mortality from cardiovascular disease increased significantly, compared with participants in the placebo group, say the authors.

At the termination of the trial, however, they have continued to follow all volunteers by phone and by mail until 31 December 2001. The monitoring results are published in the "Journal of the National Cancer Institute." They show that the risk of lung cancer is 12% higher and that of all-cause mortality 8% higher compared to people who never received beta-carotene and retinyl palmitate.

In contrast, the relative risk of mortality from cardiovascular disease is rapidly lowered to the level of those not exposed to these two dietary supplements people after stopping the test.

In general, women who had received these supplements as part of the study presented during the post-interventional phase of greatest excess risk of lung cancer mortality by cardiovascular disease and all causes that men (respectively 33% against 14% against 44% -7% -2% against 37%).

The authors conclude that the negative effects of beta-carotene and retinyl palmitate on the incidence of lung cancer and all-cause mortality in smokers and people exposed to asbestos persist several years after stopping their consumption .