30 Mar 2015 --- Lettuce, one of the indispensable vegetables in the Mediterranean diet, is a food that greatly benefits health, mainly because it is rich in antioxidants. But not all lettuce varieties have the same antioxidant effect. According to a study led by the researcher Usue Pérez-López of the Department of Plant Biology and Ecology of the UPV/EHU's Faculty of Science and Technology, the colour of the leaves of these vegetables determines the speed at which their compounds act.