Drinking a good amount of water and having an active lifestyle appear to reduce the risk of colorectal cancer in men. These findings add to the evidence that leisure-time activity may reduce colon-cancer risk, not only in high-risk but also in low-risk populations, and support the potential beneficial effect of increased water intake in reducing colorectal cancer risk. Those men who consumed the most water had a 92% lower risk of rectal cancer than those who drank the least water. What's more, those men with the most active lifestyles had 83% lower risk of colon cancer compared to men with sedentary lifestyles.

Curiously, the investigators found no link between water intake or exercise and colorectal cancer in women. However, past studies have found that people who exercise -- regardless of gender -- have a lower risk of colorectal cancer. The researchers note that it is possible that the number of women in the study, 71, was too small to detect an association. Or that the women who were sedentary in their leisure time actually engaged in heavy physical activity, such as washing clothes by hand, house-cleaning, or farming -- which would mask the association.

The study could not determine why water intake or physical activity decreased the cancer risk. However, one hypothesis is that exercise stimulates the colon and decreases the period of time that potential carcinogens in partially digested food are in contact with the intestinal lining. Similarly, increased water intake may be an important factor in reducing colon cancer risk by decreasing bowel transit time or by decreasing the concentration of carcinogenic compounds in the water phase.

International Journal of Cancer 1999;82:484-489.

COMMENT: More evidence to keep that water intake up. Ideally, one needs to consume 1quart for every 50 pounds of body weight. This amount increases with an increase in activity as you will perspire more. This may be difficult to do, unless one is seriously intentional about it. I could not get this much water in, until I began bringing my water into my work space and drinking it all day long while I was with patients. Those of you who have been in my office recently may have noticed that. The extra water will initially increase one’s visit to the rest room, but that improves with time as one’s tissues become healthier and more hydrated.