Calcium is the most abundant mineral in the human body, widely known for its role as a neurotransmitter trigger, in muscle contraction, and normal bone growth and development. Studies indicate the mineral also helps to protect against colon cancer.
A study conducted by Denise Govers at the Netherlands Institute for Dairy Research looked at the importance of bile acids and their cytotoxicity in the colonic epithelium. Bile is secreted by the gall bladder into the small intestine between meals to aid the digestion of fat. Bile production increases according to dietary fat intake, and along with fatty acids, can act as wetting agents in the colonic lumen. It is believed that they stimulate crypt cell proliferation, increasing the risk of colon cancer.
Several studies have concluded that calcium interacts with bile and fatty acids in the intestinal lumen to form an insoluble complex, reducing their lytic activity. As a result, this calcium precipitate is flushed out of the system, as opposed to being absorbed or sticking to the colon epithelium. Gover’s study involved rats that were fed diets varying in calcium intake. The rats’ fecal water was added to isolated human red blood cells to determine haemolysis levels. Haemolysis, or red blood cell destruction, was inhibited in rat fecal water that contained the highest calcium levels. This test established calcium’s protective effect in reducing the cytolytic properties of intestinal contents, as well as the bile acid concentration of fecal water.
Several other human studies using dairy product calcium sources have reached similar conclusions, with milk providing the most significant benefits. It is suggested that bile acids may promote colon cancer through an indirect mechanism, potentially acting via a signal transduction pathway to increase production of a pro-inflammatory molecule involved in many illnesses. Bile acids could also make immature goblet cells resistant to cell death, crucial to maintaining normal physiologic function, as it ensures destruction of unwanted cells.
Calcium can be obtained from a wide variety of sources. Dairy products such as milk, yogurt, and cheese, as well as turnips, broccoli, kale, brussel sprouts, and fortified soy milk are excellent sources. The daily calcium recommendation for a healthy adult is 1,000 mg. Vitamin D intake should also be maintained alongside calcium, as it significantly increases calcium absorption. Supplementation is only necessary for the elderly.
Colon cancer is the second leading cause of cancer deaths in the United States, although researchers believe it’s still too early to change the recommended dietary intake of calcium.
