health guides

It’s in the leaves

Tea is widely regarded for its potential health benefits, which range from cholesterol-lowering effects to diabetes and cancer prevention. Tea leaves are rich in polyphenols called catechins—antioxidant compounds that may prevent DNA damage and inhibit tumour cell growth, invasion, and blood vessel formation. The best-known tea catechin is called epigallocatchin-3-gallate, or EGCG.

Protect your tummy with tea

A few analyses have suggested that tea might protect against gastrointestinal cancers, but others have failed to find an effect. To see if tea drinking affected the risk of digestive system cancers in women, researchers studied 69,310 Chinese women for 11 years as part of the Shanghai Women’s Health Study.

Over the course of the study, 1,255 gastrointestinal cancers were diagnosed in the women, including cancers of the oesophagus, pancreas, stomach, colon and rectum, gallbladder and bile duct, and liver.

• Women who drank tea three or more times per week for 6 or more months in a row had a 14% lower risk of developing gastrointestinal cancers than women who never drank tea.
• Drinking more tea was associated with even greater benefit; women who drank two to three portions of tea per day had a 21% lower risk of all digestive system cancers.
• Long-term tea consumption (for 20 years or more) reduced the risk of all digestive system cancers by 27% and colorectal cancer by 29%.
• Tea consumption seemed to be most protective against oesophageal, stomach, and colorectal cancers.

Green tea was the most common type consumed by the women.

Gastrointestinal cancers account for about 50% of cancer deaths among Chinese women. While death rates for these cancers are lower in other parts of the world, many digestive system cancers may go undetected until they have spread, making prevention that much more important.

To help lower your risk of gastrointestinal cancers,

• Don’t smoke. Smoking increases the risk for many cancers, including colorectal, liver, pancreatic, oesophageal, and stomach cancers.
• Get tested. Regular screening for colorectal cancer can help lower your risk of dying from the disease.
• Know your history. Having a first-degree relative with certain cancers may increase your risk of developing the same cancer. Your doctor may adjust the frequency or type of cancer screening based on this knowledge.
• Watch your diet. Drinking alcohol, eating salty, fatty, cured or pickled foods, and not getting enough fibre in your diet might increase your chances of developing some digestive system cancers.
• Maintain an ideal weight. Obesity is linked to a few different cancers. Reach your target weight by eating a diet rich in fresh fruits and vegetables, lean protein, whole grains, and pulses, and by getting daily exercise.

(Am J Clin Nutr 2012;96:1056–63)