Cancer of the colon and rectum is the third most common cancer and third leading cause of cancer-related death in both men and women in the U.S. Chances are you know someone afflicted with this dreaded disease. Both genetic and environmental factors, including diet and activity, play a role in colorectal cancers. Modifiable risk factors—factors that we have control over—that increase risk of colon cancer include:
inactive lifestyle
obesity
eating lots of red or processed meats
smoking
drinking moderate-to-high levels of alcohol
In fact, it is estimated that about one-quarter of colon cancer cases could be avoided by maintaining a healthy weight, exercising, not smoking, limiting alcohol and following a healthy diet.1,2
Many studies have looked at how diet and exercise affect cancer risk. One group of foods specifically—milk & milk products—may play an important role in preventing colon cancer. A variety of studies indicate that consuming more calcium and/or milk foods reduces risk of colon cancer.3,4 Calcium intakes of 1,200-1,500 mg/day, or 4 servings of milk products per day, seems to provide the most protection against colon cancer.5 This amount is the same or slightly higher than the current calcium recommendation for adults. There is new evidence that vitamin D (which is added to milk) may also protect against colorectal cancer.5,6
Some studies show that people with the highest calcium or milk intakes have a 50-60 percent lower risk of colon cancer, compared to those with lower intakes.5 The reason may be that calcium binds to cancer-causing agents in the gut and helps excrete them, reducing the risk.
The handout, Colon Cancer: What You Can Do to Prevent It, describes steps you can take to prevent this common form of cancer.
The impact of calcium and dairy foods on other types of cancer—specifically breast and prostate cancers—is also being studied. However, the findings are not consistent and more studies are needed before making any changes to our diet.
Along with the protective effect calcium and milk foods seem to have against colon cancer, they also provide other benefits such as heart health, lowering blood pressure, muscle building and bone health. To reap these benefits, the 2010 Dietary Guidelines recommend that adults consume 1,000-1,200 mg of calcium daily—the amount in 3-4 servings of milk and milk products per day. The variety of flavors and types of milk, yogurt, cheese and other dairy products make meeting this recommendation both enjoyable and healthful.