The Red Lettuce Effect

Ever wonder what causes that reddish-brown stuff that turns your fresh lettuce from a lovely green to a rather unattractive shade of rust? That’s oxidation, and it can occur in a variety of ways. One way is if you store your lettuce in an area that’s emitted high levels of ethylene, such as near avocados, bananas, or tomatoes, or if you let it sit in a paper bag that emits ethylene from the gasses produced during ripening. The other way is through light exposure. Lettuce contains natural antioxidants that protect it from damage caused by oxidation.

This is why it’s best to keep your lettuce away from produce that will wilt rapidly. Aside from this, you can try to slow the process of oxidation by storing your lettuce in a cool dark place and in an airtight container that will minimize oxygen and ethylene transfer. It’s also a good idea to store your lettuce separate from other vegetables and fruits, as they will release ethylene, which can cause your lettuce to wilt faster.

Researchers have discovered that eating a diet containing mainly red leaf lettuce can lower your cholesterol levels. In fact, a study of rats showed that when the rats ate 20% of their diet in red oak leaf lettuce for three weeks, their LDL (bad) cholesterol levels dropped significantly while their HDL cholesterol levels rose. It seems that the phytochemicals in the leaves of this type of lettuce are able to neutralize cholesterol and prevent its absorption.

Another benefit of this type of lettuce is its richness in magnesium and potassium. According to research, these minerals are crucial for the normal contraction and relaxation of the heart muscle. Insufficient intake of these nutrients has been linked to various heart conditions, including coronary heart disease and high blood pressure.

In a recent study, scientists found that red butter baby lettuce varieties with a high anthocyanin content have exceptionally strong antioxidant properties. These lettuce varieties contained higher amounts of total phenolics than the other five tested lettuce varieties, including iceberg, romaine, continental, red oak leaf and lollo rosso. Moreover, the antioxidant activity was related to the amount of lutein, a carotenoid and natural plant pigment that has been known to have powerful antioxidative properties.

This is a great finding, especially since consumers purchase their lettuce based on appearance. The results of this study show that light variations have significant effects on color intensity of lettuce, explaining the differentiation observed between different coverings. For example, open, clear and movable coverings resulted in a darker red lettuce than that grown under the shade covering. The findings suggest that light intensities can be manipulated to increase anthocyanin concentration, providing valuable information for breeding programs to develop new lettuce cultivars with high anthocyanin content.