Antioxidant
Effects differ by Leaf Color
From: University of the Basque Country
Lettuce, one of the indispensable vegetables in the 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.
So lettuces with green leaves have
antioxidants that react more slowly while red-leaf ones have a faster effect.
The results of this study have been set out in a paper "Phenolic
Composition and Related Antioxidant Properties in Differently Coloured
Lettuces: A Study by Electron Paramagnetic Resonance (EPR) Kinetics"
recently published by the ‘Journal of Agricultural and Food Chemistry'.
Free radicals harm our body by causing, in the best of cases,
ageing and, in the worse, serious diseases. Lettuce is rich in antioxidants, as
it contains compounds like phenolic acids, flavonoids, anthocyanins, and
vitamins A and C, among other things.
Green, semi-red and red leaves
To conduct this research, which started in 2011 and in
which researchers of the UPV/EHU and the University of (Italy) have
been participating, the compounds of three lettuce varieties were analysed: the
green-leaf ‘Batavia', the semi-red-leaf ‘Marvel of Four Seasons', and the
red-leaf ‘Oak Leaf'.
Using Electron Paramagnetic Resonance (EPR) techniques,
they were able to observe the behaviour of the kinetics of the compounds of
each variety. And the results show that the green-leaf lettuce contains water-soluble,
antioxidant compounds that act at a slow and intermediate speed, the red-leaf
one has compounds with intermediate and rapid kinetics, and the semi-red-leaf
one has three kinds of compounds, with a rapid, intermediate and slow speed.
As Dr Pérez-López stressed, "the fact that there are
compounds that act at different speeds does not mean that some are better or
worse than others. If we eat foods that can generate free-radical activity,
there will be some compounds that act to eliminate them more quickly.
"But at
the same time, it is also important that our bodies should acquire foods with
antioxidants that have slower kinetics so that the latter will continue to act
over a longer period of time. That is why people say that it is very interesting
to mix different types of lettuce because they have different, complementary
characteristics".
Continue reading at the University of
the Basque Country.
Lettuce image via Shutterstock.