Besides helping your body run smoothly, some evidence shows that water helps prevent certain diseases. People who have had kidney stones often can prevent further stones from forming by drinking lots of fluid. One study found that women who drank more than five glasses of water a day had a risk of colon cancer that was 45 percent less than those who drank two or fewer glasses a day.
There’s also some evidence that water consumption can help prevent bladder cancer. A study of more than 47,000 men who took in an average of more than 2 1/2 quarts of fluid each day, including water, were found to have a lower risk of bladder cancer than men who drank less than half as much.
(Source: Mayo Clinic, on the web at www.mayoclinic.com)