March 19, 2002 -- A diet rich in calcium may help reduce the risk of some types of colon cancer, according to a new study. But don't go adding calcium supplements to your daily regimen just yet. Researchers say there's a limit to the mineral's cancer-fighting abilities.
The study, published in the March 20 issue of TheJournal of the National Cancer Institute, found people who had a higher calcium intake had a lower risk of left-sided colon cancer. Men and women who got between 700 to 800 mg of calcium in their diets each day had a 40% to 50% lower risk of left-sided colon cancer compared to those who had less than 500 mg of calcium a day.
Researchers found that even a modest increase in calcium intake among people with low-calcium diets seemed to provide some protection against colon cancer. But people who already had a high-calcium diet (more than 700 mg a day) didn't reap any benefits from adding calcium supplements.
The study followed the diets and colon cancer history of about 88,000 women in the Nurses' Health Study and 47,000 men in the Health Professionals Follow-Up Study. Calcium's protective effect seemed to be limited to preventing cancers in the left-sided colon and didn't have any effect on cancers in the right side.
The authors suggest that calcium reduces colon cancer risk by slowing cell growth -- a process that, when uncontrolled, can lead to cancer.
Here are some examples of calcium-rich foods:
- 1 cup of milk -- 300 mg
- 1/2 cup of broccoli -- 35 mg
- 1/2 cup of spinach -- 120 mg
- 1.5 oz of cheddar cheese -- 300 mg
- 8 oz. of low-fat yogurt -- 300-415 mg
- 1 cup of calcium-fortified orange juice -- 300 mg