Given preliminary data in animal (proprietary data) have shown that XXS (a mixture of natural polyphenolic extracts of edible plants) has a significant and favourable effect on oxidative stress notably with a decrease in certain markers of oxidative stress and on plasma lipid parameters, the investigator proposes to study the effect of 6 months of treatment with XXS in a controlled study against placebo in a population of persons presenting a lipid profile at the upper limit of normal.