Submitted to: Encyclopedia of Human Nutrition
Publication Type: Book / chapter
Publication Acceptance Date: 8/1/2005
Publication Date: 12/1/2005
Citation: Allen, L.H., Kerstetter, J.E. Calcium. Encyclopedia of Human Nutrition. 2005, Elsevier Ltd. 253-259. Interpretive Summary:
Technical Abstract: Calcium is an essential nutrient. While most of the calcium in the body is found in bones and teeth, the other 1% has critical, life-sustaining functions. Most people in the world, including those in industrialized countries, fail to consume the recommended amounts of calcium, which will ultimately result in poor bone health and increase the risk of osteoporosis. Adequate calcium intake is critical to the achievement of peak bone mass in the first several decades of life, the retention of bone during middle adulthood and the minimization of bone loss during the last several decades. Without adequate intake, the intestine, bone, and renal systems have intricate ways retaining more calcium and normalizing serum calcium levels. These three primary tissues of calcium homeostasis (intestine, bone, and kidneys) are dynamic in their handling of calcium, reacting to dietary intake, physiological need or disease process. In this review, we present the details of calcium absorption, regulation, function, metabolism, and excretion as well as the changes in calcium physiology during the lifespan.