Disease-fighting power in your cup

Enjoyed throughout Asia for centuries, green tea is produced by heating, rolling, and drying the fresh leaves of the Camellia sinensis plant. Unlike black tea, which is produced from the same plant, green tea is not fermented; skipping the fermentation step helps preserve the tea’s catechin content.

Catechins are believed to play a role in preventing chronic diseases like cancer (including colon, breast, and prostate cancers) and heart disease. The only catch is that when these disease-fighting substances are drunk as a tea, they might not survive the digestive process.

This study looked at the effect of how you take your tea—with different preservatives such as ascorbic acid (vitamin C) or with various creamers or juices—on the levels of catechins available for absorption. “Teas and tea mixes could be of great value in reducing disease severity and risk if factors associated with its protective activity are identified,” the authors noted.

Get an antioxidant lift with lemon

Citrus juices significantly increased catechin levels following laboratory-simulated digestion, as did ascorbic acid, soymilk, rice milk, and cow’s milk. “drinks prepared with ascorbic acid contents as low as 50% of the RDI [recommended daily intake] would likely provide effective protection,” the team commented. This amount is found in many ready-to-drink tea preparations.

Adding different creamers to green tea increased the available catechin levels from less than 20% to as much as 69%. Citrus juices were the clear winner, though, resulting in the maximum catechin recovery of any preparation.

The highest catechin levels were found by adding these citrus sources, respectively:

• Lemon juice
• Orange juice
• Lime juice
• Grapefruit juice

While different tea preparations still need to be studied under true digestive conditions, adding some lemon to your tea could be a flavourful way to boost the benefits of this ancient infusion. Keep a fresh lemon or a bottle of preservative-free natural lemon juice in the refrigerator as a handy accompaniment to your green tea.

(Mol Nutr Food Res 2007;51:1152–62)