Safety evaluation of meso-zeaxanthin

Meso-zeaxanthin is a xanthophyll family member of carotenoids. Having closely related structures, meso-zeaxanthin, zeaxanthin and lutein have high concentration in macula and are believed to play a major role in protecting retinal constituents from free radicals. Due to the current technical difficulties in measurement, the presence of meso-zeaxanthin in human blood or tissues has not been reported except in human eyes, which has promoted scientists' interest in exploring potential health benefits of meso-zeaxanthin. Herein, we report a complete toxicological safety assessment of meso-zeaxanthin for use as an ingredient in food, dietary and nutritional supplements, as well as medical food. Assays of acute toxicity, genetic toxicity (Ames test, mice bone marrow erythrocyte micronucleus and mice sperm abnormality) and 90-day sub-chronic toxicity were performed. In the acute oral toxicity tests, maximum tolerable dose was more than 10.0 g/kg bw in SD rats and ICR mice, and showed no toxicological signs during the period of the study. The testing results for three terms of hereditary toxicity (Ames test, mice bone marrow erythrocyte micronucleus and mice sperm abnormality) were all negative. For 90-day feeding of meso-zeaxanthin at the dosage of 300 mg/kg/d in both male and female SD rats, there is no noticeable toxicological effects observed. Therefore, meso-zeaxanthin has no acute toxicity and no genotoxicity and the use of meso-zeaxanthin is safe at dose of 300 mg/kg bw/day in rats from a 90-day feeding study. After the application of a 100-fold safety factor, we obtained the ADI (acceptable daily intake) value of 3 mg/kg body weight per day.