English poet William Cowper deserves a nutritional shout-out for being the first to state: “Variety's the very spice of life that gives it all its flavor.”
He probably wasn’t talking about food but it is so applicable. One of the essential commandments of healthy eating is to enjoy a variety of foods to ensure an adequate intake of vitamins, minerals and phytonutrients. And now research has given us another reason to pursue a variety of veggies.
Researchers at the University of the Basque Country took a deep dive into the antioxidant properties of lettuce. Antioxidants are the molecules in foods that interact with free radicals in the body to lessen their impact on aging, damaging cells and promoting disease. Eating a variety of foods provides a range of antioxidants such as vitamins C and E, and plants rich in flavonoids (parsley, onions, green and black tea, bananas and citrus fruits) and in anthocyanins (blueberries, cranberries, raspberries), to name a few.
In this study three types of colorful lettuce were examined for the kinetics, or speed with which the antioxidants act. A green leaf Batavia, a semi red leaf and a full red leaf lettuce were tested. They found that the green leaf lettuce antioxidant compounds act at a slow and intermediate speed, the red leaf lettuce had intermediate and rapid kinetics and the semi red leaf had all three speeds.
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This does not make any of the lettuce good or bad. Having a combination of speeds means that the antioxidants are going to work right away and also continuing to act over a longer period of time to keep fighting those nasty free radicals. Although not tested, the kinetics of antioxidants in all fruits and vegetables probably have different speeds of action.
This is interesting theoretical information but its practical meaning goes back to Cowper’s famous quote. Enjoying a variety of antioxidant rich foods covers all time periods and provides the widest array of vitamins and minerals as well as antioxidants. It’s time to turn in the iceberg lettuce wedge for a beautiful spring mix.
Sheah Rarback is a registered dietitian on the faculty of the University of Miami Leonard M. Miller School of Medicine. Follow her on Twitter @sheahrarback.