Colorectal cancer, also known as bowel cancer, is a common form of cancer that affects the colon or rectum. The health information website, Patient UK, states that although the exact cause of colorectal cancer is unclear, risk factors may include age, family history of the disease, obesity and drinking alcohol. Colorectal cancer is treated by surgically removing the tumor; chemotherapy and radiotherapy may also be used along with surgery. Some dietary supplements, including calcium, may help to prevent colorectal cancer although evidence to prove this is mixed. Talk to your doctor before taking a calcium supplement for cancer and don't use it in place of medical treatments.
Properties and Effects
Calcium is a mineral. It plays an important role in a number of biological processes including muscle function, intracellular signaling, hormone secretion and bone formation. It may play a role in the prevention or treatment of a number of conditions including hypertension, cardiovascular disease and osteoporosis. The Office of Dietary Supplements states that data from numerous studies suggest that it may also reduce the risk of developing cancer of the colon and rectum.
Sources and Administration
A host of foods contain calcium including yogurt, milk, sardines, cheddar cheese, tofu, spinach and fortified cereals. You can also take calcium as a dietary supplement. Guidance regarding the amount needed to prevent colorectal cancer is lacking. The Office of Dietary Supplements notes that the upper tolerable intake of calcium is 2,500 mg for males and females aged 19 to 50, and 2,000 mg for males and females older than 51. Do not take higher amounts without first consulting your doctor.
Scientific Evidence
An analysis of data from two randomized controlled clinical trials published in the January 2008 "Cochrane Database of Systematic Reviews," demonstrated that supplemental calcium may help to prevent colorectal cancer to a moderate degree. The review concluded, however, that there was insufficient evidence to recommend taking calcium supplements to help prevent colorectal cancer.
Safety Considerations
Taking too much calcium may increase the risk of developing renal insufficiency and kidney stones. It may also cause constipation. The Office of Dietary Supplements says that a high calcium intake may increase the risk of prostate cancer, but adds that this effect has not been proven conclusively. Bear in mind that calcium supplements may interact with other medicines you are taking, including some osteoporosis medicines and antibiotics.
