Melatonin present in beer contributes to increase the levels of melatonin and antioxidant capacity of the human serum

Background & aim: Melatonin is a molecule with antioxidative properties including direct free radical scavenging and indirect stimulatory actions on a variety of antioxidative enzymes which further promote its ability to reduce the toxicity of radicals and their associated reactants. Beer is an integral element of the diet of numerous people and is rich in antioxidants. We analyzed if melatonin is present in beer and if so, at what concentration. It further determines whether the moderate consumption of beer has an effect on the total antioxidant Status (TAS) of human serum. Methods: We analyzed 18 brands of beer with different percentage of alcohol content in order to determine the concentration of melatonin. Serum samples were collected from 7 healthy volunteers. These samples were used to measure melatonin and TAS on basal conditions and after drinking beer. Results: Showed that all the beer analyzed did indeed contain melatonin and the more they have got, the greater was its degree of alcohol. Both melatonin and TAS in human serum increased after drinking beer. Conclusions: Melatonin present in the beer does contribute to the total antioxidative capability of human serum and moderate beer consumption can protect organism from overall oxidative stress. (C) 2009 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.