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Nutrition & Product Information
Calcium Summit II
Bone Health and Beyond: The Critical Role of Calcium
Moderator: Marc S. Jacobson, M.D.
Professor of Pediatrics and Epidemiology
Albert Einstein College of Medicine
Director, Center for Atherosclerosis Prevention Schneider Children's Hospital
The American Academy of Pediatrics (AAP) has several resources available to help pediatricians and other health professionals reach and teach America's youth about the critical role of calcium in health. These resources include the Pediatric Nutrition Handbook (23) and nutrition-related policy statements such as one on calcium requirements of infants, children, and adolescents, one on the practical significance of lactose intolerance, and another on the use and misuse of fruit juice (24). These policy statements are available on the internet at www.aap.org . The AAP's policy statement on calcium urges pediatricians to recommend milk, cheese, yogurt, and other calcium-rich foods for children's daily diets to help prevent future risk of osteoporosis, as well as decrease the risk of childhood and adolescent fractures. This session examined recent research related to calcium, including bone health, as well as other emerging areas.
Bone Health Hazards: the Make-It-Or-Break-It Teenage Years
Connie Weaver, Ph.D.
Distinguished Professor and Head of the Department of Foods and Nutrition Purdue University
Adolescence is a critical time to optimize bone health, given that approximately 50% of skeletal mass is accrued during adolescent years. In girls, 95% of total body mineral mass is accumulated by age 17 and 99% by age 27 (25). Optimizing bone health during adolescence not only reduces future risk of osteoporosis, but also helps to prevent forearm fractures during youth (26,27).
Randomized, controlled trials involving children and adolescents demonstrate that increasing intake of calcium increases bone mass and bone density (25). To determine how much calcium is needed to optimize adolescents' peak bone mass, researchers at Purdue University examined calcium retention in girls aged 11 to 14 years who consumed calcium intakes ranging from 600 to 2,300 mg/day. Increasing calcium from a usual intake of 918 mg/day to the recommended 1,300 mg/day increased calcium retention by 112 mg/day during the three-week study. If maintained for a year, this could lead to an estimated 4% increase in skeletal mass in Caucasian girls.
Because African American girls utilize calcium more efficiently than do Caucasian girls, the calcium intake to ensure optimal skeletal status in African American girls is lower than that for Caucasian girls. Lactose malabsorption need not preclude African American adolescent girls from consuming recommended servings of milk and other dairy foods (20, 21).
Current calcium intakes of adolescents are well below recommended levels (7,9). Findings from ongoing studies indicate that four to five servings/day of calcium-rich foods such as milk and other dairy products are needed to optimize peak bone mass during adolescence.
Osteoporosis is a pediatric disease with geriatric consequences. With low calcium intake levels during important bone growth periods, today's youth faces a serious public health problem in the future.
Evidence of Osteoporosis in African American and Hispanic Communities: Data from the National Osteoporosis Risk Assessment
Ethel Siris, M.D.
Medical Director, National Osteoporosis Risk Assessment
Madeline C. Stabile Professor of Clinical Medicine Columbia University
Director, Toni Stabile Osteoporosis Center, Columbia Presbyterian Medical Center
Recent results from the National Osteoporosis Risk Assessment (NORA) study demonstrate an unexpectedly high prevalence of undetected low bone mass in ambulatory postmenopausal women (28). Overall, nearly 40% of the women tested had low bone mass and an additional 7% had osteoporosis. Compared to women with normal bone mineral density, women with osteoporosis experienced a four-fold higher rate of fracture, and those with low bone mass experienced a 1.8-fold higher rate of fracture.
NORA is a longitudinal observational study involving more than 200,000 postmenopausal women aged 50 years or older with no previous diagnosis of osteoporosis, recruited from more than 4,200 primary care practices in 34 states. Although most of the participants (90%) were Caucasian, this is by far the largest study of osteoporosis among racial/ethnic minority women.
Potential risk factors for osteoporosis included: advancing age, personal or family history of fracture, Asian or Hispanic heritage, cigarette smoking, and cortisone use. Compared to Caucasian women, the risk of osteoporosis was 1.56 times higher for Asian women, 1.31 times higher for Hispanic women, and 45% lower for African American women. Although low bone mineral density was significantly less prevalent among African Americans, 32% of African American women had low bone mass and 4% had osteoporosis. Bone protective factors included higher body mass index, estrogen use, diuretic use, and exercise.
The findings from NORA led researchers to conclude, "Given the economic and social costs of osteoporotic fractures, strategies to identify and manage osteoporosis in the primary care setting need to be established and implemented" (28).
Calcium's Expanding Role: Exploring New Areas of Emerging Research
Robert P. Heaney, M.D.
John A. Creighton University Professor and Professor of Medicine Creighton University
While calcium's beneficial effect on bone health has long been established, new research points to a much wider range of potential health benefits (29, 30). In addition to osteoporosis, adequate calcium intake may reduce the risk for hypertension, pre-eclampsia, colon cancer, obesity, kidney stones, premenstrual syndrome, and polycystic ovary syndrome (29).
A plausible explanation exists for calcium's role in multiple body systems (30). Diseases of calcium nutrition deficiency occur when chronic low calcium intakes result in: a) depletion of skeletal reserves (e.g., osteoporosis), b) failure to detoxify digestive byproducts (e.g., colon cancer, kidney stones), and c) adaptive responses mediated by hormonal reactions to intracellular calcium (e.g., hypertension, obesity, premenstrual syndrome, polycystic ovary syndrome) (30). For example, when calcium intake is low, there is insufficient unabsorbed calcium in the intestinal lumen to neutralize cancer promoters such as unabsorbed fatty acids and bile, or bind oxalate which is a risk factor for kidney stones (30).
At present, dietary recommendations for calcium are based on the need for skeletal health (9), which ignores the non-skeletal health effects of a calcium-rich diet. Some population groups such as African Americans have lower calcium needs for skeletal health than do Caucasians and Orientals. The calcium need for optimal skeletal status in African Americans may fail to protect them from non-skeletal diseases such as hypertension, stroke, colon cancer, and coronary artery disease, for which they are at a disproportionately high risk. The optimal calcium intake for total body health is estimated to be more than 1,200 mg/day for all adults (30).
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