There is good news for people who can't get by without their daily fix of coffee or tea. These beverages may also be protecting their DNA, the building blocks of all of the cells in the body, from damage caused by normal metabolic processes and environmental factors like natural UV radiation. Past research has shown that cells with damaged DNA can trigger ailments from cancer to cataracts to infertility.
One type of DNA damage that coffee may protect against is oxidation, which is when the bases of the DNA strands take on oxygen. Then the DNA stands a greater chance of forming mutated cells when they replicate.
Researchers in Europe believe that increasing your intake of antioxidants like the quinines found in coffee can slow down damage to DNA. They found that people who drank 800 ml of coffee a day for five days had a reduction in the rate of oxidation in their DNA, while the level of oxidation for water drinkers stayed about the same.
Green tea may have similar health benefits, according to a recent study in Hong Kong which showed that polyphenols like the tannins found in green tea can also protect DNA from oxidation.
Green tea may also keep DNA from aging too quickly. As DNA replicates and the body ages, the strands at the end of the chromasomes get shorter. By measuring these strands, researchers in China noted that people who drank three cups of tea a day had "younger" DNA than those who didn't drink tea. The researchers speculate that younger DNA may add as many as five years to the lives of the tea drinkers.