Some previous studies have suggested that coffee and tea may lower the risk of cancer, but others show that they could increase the risk. Tea, for instance, contains antioxidants that in theory help prevent cancer but also has polyamines which in theory promote cancer. Sugar-sweetened soft drinks are associated with weight gain, obesity and other conditions that are potential risk factors for colon cancer.

For this study, Xuehong Zhang and colleagues at the Harvard School of Public Health analysed data from 13 studies conducted in North America and Europe. Among 731,441 study participants, there were 5,604 who developed colon cancer. Those who drank large amounts of coffee, more than six 8oz cups a day, were no more likely to develop the disease than those who drank less.

Likewise, those who drank more than 18oz daily of sugar-sweetened, carbonated beverages had no higher risk of colon cancer. However, the authors note that the results for sugar-sweetened carbonated beverages should be interpreted with caution, because only 2% of the study population drank over 18oz of these beverages daily.

The results were similar regardless of sex, smoking status, alcohol consumption, body mass index, level of physical activity, and location of the tumor.

The authors found a modest association between drinking high amounts of non-herbal tea, more than four 8oz cups a day, and colon cancer risk. However, they note that very few people in the study drank that much tea and that the association could be due to chance, says a Harvard release.

"Drinking coffee or sugar-sweetened carbonated soft drinks was not associated with colon cancer risk," the researchers conclude. "However, a modest positive association with higher tea consumption is possible and requires further study."

These findings were published online in the Journal of the National Cancer Institute.

From the May 24, 2010, Prepared Foods E-dition