. "4 Review of Potential Indicators of Adequacy and Selection of Indicators: Calcium and Vitamin D." Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: The National Academies Press, 2011.
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DRI Dietary Reference Intakes Calcium Vitamin D
sons of any age in the study achieved neutral calcium balance at calcium intakes of 741 mg/day.
Although these data may be relevant for the younger aging male, the Hunt and Johnson (2007) analysis may not be adequate for considering specific issues of bone loss due to aging among men; there were only two men in the age range of 51 to 70 years and no men over the age of 70 years in the analysis. Further, it is uncertain what proportion of women in the Hunt and Johnson (2007) study were menopausal, although approximately half were over the age of 50 years.
Heaney et al. (1977), in examining 130 Catholic nuns as part of a longitudinal study, reported that neutral calcium balance during the perimenopausal state for these women (between the ages of 35 and 50 years) was achieved at 1,240 mg/day. This intake is notably higher than that reported by Hunt and Johnson (2007). In a second study of the same group of women (n = 168), Heaney et al. (1978) reported that perimenopausal and estrogen-treated women reached neutral calcium balance with calcium intakes of 990 mg/day, whereas untreated postmenopausal women required 1,504 mg of calcium per day for neutral calcium balance. This suggests, in contrast to the findings of Hunt and Johnson (2007), that menopausal state may be relevant to considerations of calcium requirements. In any case, because the indicator of interest is bone health, other measures, such as bone density and fracture risk are also considered.
Bone mineral density and fracture risk: Calcium Fracture risk occurs in the later years of life and can be useful as an indicator of bone health, but fractures are less common in persons less than 70 years of age. Therefore, as an indicator, it is not particularly revealing as far as the effects of nutrient intake in slowing the bone loss of early menopause, when many women are in their 50s. It is also of questionable relevance to men less than 70 years of age who generally have yet to experience the full impact of bone loss due to aging. However, BMD measures are predictive of future fractures and can serve as a relevant indicator to ensure bone health to the extent possible during the onset of menopause and during the early aging process.
Regarding BMD measures and calcium intake among younger menopausal women, the AHRQ analyses are not specifically helpful in that the analyses used primarily studies that supplemented participants with both vitamin D and calcium, and neither AHRQ analysis addressed calcium alone relative to bone health. One report reviewed by AHRQ, which used a combination of calcium and vitamin D supplements, should be noted, especially given the large size of the cohort. The study (Jackson et al., 2006), stemming from the WHI, randomly assigned more than 36,000 post-menopausal women between the ages of 50 and 79 years (mean = 62 years) to a placebo or 1,000 mg of calcium with a supplement of 400 IU of vitamin D3. Fractures were ascertained during a period of about 7 years, and