Adding citrus juices or vitamin C to green tea may raise its antioxidant goodness, a new study suggests.

The antioxidants in question are called catechins, believed to be responsible for some of green tea's reported health benefits, such as reducing the risk of cancer, heart attack and stroke.

"Although these results are preliminary, I think it's encouraging that a big part of the puzzle comes down to simple chemistry," lead author Mario Ferruzzi, assistant professor of food science at Purdue University in West Lafayette, Ind., said in a prepared statement.

Using a laboratory model that simulates digestion in the stomach and small intestine, Ferruzzi tested green tea with a number of additives, including juices and creamers.

He found that citrus juice increased recoverable (absorbable) catechin levels by more than five times, while vitamin C (ascorbic acid) boosted recoverable levels of the two most abundant catechins by six and 13 times.

The findings were published in the journal Molecular Nutrition and Food Research.

Citrus juices and vitamin C may interact with catechins to prevent degradation in the intestines, Ferruzzi said.

"If you want more out of your green tea, add some citrus juices to your cup after brewing or pick a ready-to-drink product formulated with ascorbic acid," he suggested.

Ferruzzi is currently conducting a study examining whether citrus juices and vitamin C increase catechin absorption in lab animals.