Safety evaluation of synthetic beta-carotene

The safety of beta-carotene was reassessed by evaluating the relevant liter ature on the beneficial and adverse effects of beta-carotene on cancer and, in particular, by evaluating the results of toxicity studies. beta-Caroten e appeared neither genotoxic nor reprotoxic or teratogenic, and no signs of organ toxicity have been found in subacute, subchronic, or chronic oral to xicity studies in experimental animals receiving doses of up to 1000 mg/ da y beta-carotene per kg body weight via the diet. Synthetic beta-carotene di d not exert any carcinogenic effect in Sprague-Dawley rats or in CD1 mice. An enhanced risk of lung cancer was found in two human intervention studies . Although dose and (timing of) exposure, smoking status, and imbalance of antioxidant defense have been recognized as potential factors accounting fo r the outcome of these studies, a conclusive explanation has not yet been f ound. It is concluded that exposure to beta-carotene resulting in mean plas ma concentrations of no more than 2.2 mu mol/l (1.2 mg/ml) is safe to the g eneral population. By contrast, in heavy smokers higher plasma concentratio ns may be associated with a higher lung cancer risk.