May 6, 2010 -- Java junkies, rejoice: New research shows that drinking more than six 8-ounce cups of coffee per day does not increase your risk of developing colon cancer.
What’s more, drinking more than 18 ounces of sugary soda each day also does not appear to increase the risk of colon cancer, according to the new study that appears online in Journal of the National Cancer Institute.
“Coffee drinkers should be reassured that there is no increased risk of colon cancer and there is no reason to change their consumption,” says study researcher Xuehong Zhang, MD, ScD, an epidemiologist at the Harvard School of Public Health in Boston.
While sugary soft drink connoisseurs may not raise their risk of colon cancer, these “sweetened soft drinks are associated with weight gain, obesity, and type 2 diabetes for certain,” he tells WebMD. “Limiting your intake is recommended because of the risk of other health issues.”
Coffee, Soda, Tea and Cancer
Until now, the literature on how coffee and tea affect cancer risk has been mixed. Some studies have shown that drinking coffee and tea may lower the risk of cancer, but other studies have found that these beverages may increase the risk. For example, tea contains both cancer-fighting antioxidants and potentially cancer-promoting polyamines.
In the new study, researchers analyzed data from 13 studies totaling more than 731,441 participants. Of these, 5,604 developed colon cancer.
- Those who drank more than six 8-ounce cups of coffee per day were no more likely to develop colon cancer than those who drank less coffee or no coffee.
- The same held for those who drank more than 18 ounces of sugar-sweetened sodas each day, when compared to people who drank less soda or no soda.
- People who drank more than four 8-ounce cups of tea per day had a 28% greater risk of developing colon cancer than those who drank less tea or no tea.
Only 2% of the study population actually drank such high amounts of tea and soft drinks per day, which may have skewed the findings, the researchers point out.
The new study also had some other limitations; namely, that all of the populations studied were European, and the findings -- or the drinking habits -- may not apply to other populations. They researchers did not measure the health effects of adding milk or sugar to the coffee or tea, diet soda, or different types of tea, all of which could play a role in colon cancer risk.
Soda Health Risks Questioned
In an accompanying editorial, Cynthia Thomson, PhD, and Maria Elena Martinez, PhD, of the Arizona Cancer Center in Tucson, write that “these results are particularly important given the substantial increase in sweetened beverage consumption that has occurred over the past 50 years worldwide.”
Still, they write, more study is needed to help elucidate the link between sugary sodas and cancer risk. “Contrary to coffee and tea consumption, intake of sweetened beverages begins in childhood in many countries,” they write. "Furthermore, sweetened beverage consumption is generally much lower among older adults. These differences in exposure suggest that intake of sweetened beverages may need to be assessed earlier in life to adequately assess its association with health outcomes.”