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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Healthy Body Weight Research » Research » Publications at this Location » Publication #206040
Title: Calcium requirement: new estimations for men and women by cross-sectional statistical analyses of calcium balance data from metabolic studies

Author
item Hunt, Curtiss
item JOHNSON, LUANN - UNIV NORTH DAKOTA

Submitted to: The American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2007
Publication Date: 10/1/2007
Citation: Hunt, C., Johnson, L.K. 2007. Calcium requirement: new estimations for men and women by cross-sectional statistical analyses of calcium balance data from metabolic studies. American Journal of Clinical Nutrition. 86:1054-63.

Interpretive Summary: Persons who do not have enough calcium in their diets may be at higher risk for developing osteoporosis or diseases of the heart and arteries. There is not enough scientific information available to recommend how much calcium should be eaten every day on average to replace the calcium that is lost every day in the urine, feces, and sweat. Therefore, we examined the information from 19 studies with adults (73 women who were between 20 and 75 years of age; 81 men who were between 19 and 64 years of age). The studies were conducted at the USDA ARS Grand Forks Human Nutrition Research Center over a period of 19 years. The scientists carefully measured all of the calcium that each of these persons consumed and all of the calcium that was excreted in the urine and feces. A very small amount of calcium was lost in the sweat (in young men, only 3 mg per day on average). After examining all of the information, it was estimated that adults need to consume about 741 milligrams of calcium every day on average to replace the calcium that is lost from the body. The age or sex of the person did not change the amount of calcium that was needed to keep the body in calcium balance. The information from this study greatly expands the information currently available on calcium balance and should be useful in making better estimates of how much dietary calcium adults require to maximize their health status.

Technical Abstract: Background: Low intakes of calcium (Ca) are associated with increased risk of both osteoporosis and cardiovascular disease. Objective: To provide new estimates of the average Ca requirement for men and women, we determined the dietary Ca intake required to maintain neutral Ca balance. Design: Ca balance data (Ca intake – [fecal Ca + urinary Ca]) were collected from 154 subjects (women: n=73, weight=77.1±18.5 kg, age=47.0±18.5 y [range: 20-75 y]; men: n=81, weight=76.6±12.6 kg, age=28.2±7.7 y [range: 19-64 y]) who participated in 19 different tightly-controlled feeding studies conducted in a metabolic unit. Balance data from the last 6-12 d of each dietary period (min. length 18 d) of each study (1-9 observations per subject) were analyzed. Data were excluded if individual intakes of Mg, Cu, Fe, P, or Zn fell below the Estimated Average Requirements or exceeded the 99th %tile of 1994 CSFII usual intakes (for Fe, above the UL). Daily intakes of Ca ranged between 415 and 1740 mg. The relation between intake and output was examined by fitting random coefficient models using SAS Proc Mixed. Coefficients were included to test for gender and age differences. Results: The models predicted neutral Ca balance (defined as Ca output (Y) equal to Ca intake (C)) of 741 mg/d [507 – 1035, 95% prediction interval (PI); Y = 148.29 + 0.80C], 9.4 mg/kg/d [6.4 – 12.9, 95% PI; Y = 1.44 = 0.85C], or 0.28 mg/kcal/d [0.19 – 0.38, 95% PI; Y = 0.051 + 0.816]. Neither age nor sex affected the estimates when expressed as mg/d or mg/kg/d. Conclusion: The findings suggest a lower Ca requirement for men and women than some estimated previously.