A Review of Calcium Supplements and Cardiovascular Disease Risk
ABSTRACT A group of academic and industry experts in the fields of nutrition, cardiology, epidemiology, food science, bone health, and integrative medicine examined the data on the relationship between calcium supplement use and risk of cardiovascular events, with an emphasis on 4 of the Bradford Hill criteria for causal inference: strength, consistency, dose-response, and biological plausibility. Results from 2 epidemiological studies and a meta-analysis of randomized, controlled clinical trials, including a subgroup analysis from the Women's Health Initiative, have prompted concern about a potential association between calcium supplement use and a small increase in the risk of adverse cardiovascular events. However, a number of issues with the studies, such as inadequate compliance with the intervention, use of nontrial calcium supplements, potential bias in event ascertainment, and lack of information on and adjustment for known cardiovascular risk determinants, suggest that bias and confounding cannot be excluded as explanations for the reported associations. Findings from other cohort studies also suggest no detrimental effect of calcium from diet or supplements, with or without vitamin D, on cardiovascular disease risk. In addition, little evidence exists for plausible biological mechanisms to link calcium supplement use with adverse cardiovascular outcomes. The authors do not believe that the evidence presented to date regarding the hypothesized relationship between calcium supplement use and increased cardiovascular disease risk is sufficient to warrant a change in the Institute of Medicine recommendations, which advocate use of supplements to promote optimal bone health in individuals who do not obtain recommended intakes of calcium through dietary sources.
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ABSTRACT: Appropriate calcium intake is necessary for the accrual and maintenance of bone mass. A significant proportion of the world's population does not haveadequate calcium intake, and thus, supplementation plays akey role in maintaining bone homeostasis and other aspects of health. Since a series of reports fromthe Auckland calcium study and metaanalysisindicated that calcium supplementation was associated withan increased risk for adverse cardiovascular events,concern over the safety of calcium supplementation has grown; however, considerable inconsistencies in the reproducibility were found and questions regarding the study methodologies have been raised. In addition, since the increased adverse cardiovascular events by calcium supplementation were observed in calcium-replete-subjects, it should be clarified whether the same risk profile would be observed in countries with low calcium intake. Dietary calcium intake varies widely across the world; cardiovascular event risk factors and outcomes also vary and appear to be the opposite of calcium intake levels. Furthermore, the effects of calcium supplementation were shown to depend on dietary calcium intake, with a better bone mineral density response for low calcium intake subjects compared to that in calciumreplete subjects. Based on these evidences, the risk-benefit ratio of calcium supplement is likely to be different in different region of the world. Therefore, accumulation of evidence to establish population-specific guidelines for calcium supplementation is warranted before extrapolating the results obtained from a limited number of studies to the other people with different age, gender, ethnicity and risk profile across the world. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.Journal of Cellular Biochemistry 02/2015; DOI:10.1002/jcb.25119 · 3.37 Impact Factor
Article: The Role of Calcium in Human Aging[Show abstract] [Hide abstract]
ABSTRACT: Calcium is an essential nutrient that is necessary for many functions in human health. Calcium is the most abundant mineral in the body with 99% found in teeth and bone. Only 1% is found in serum. The serum calcium level is tightly monitored to remain within normal range by a complex metabolic process. Calcium metabolism involves other nutrients including protein, vitamin D, and phosphorus. Bone formation and maintenance is a lifelong process. Early attention to strong bones in childhood and adulthood will provide more stable bone mass during the aging years. Research has shown that adequate calcium intake can reduce the risk of fractures, osteoporosis, and diabetes in some populations. The dietary requirements of calcium and other collaborative nutrients vary slightly around the world. Lactose intolerance due to lactase deficiency is a common cause of low calcium intake. Strategies will be discussed for addressing this potential barrier to adequate intake. The purpose of this narrative review is a) to examine the role of calcium in human health, b) to compare nutrient requirements for calcium across lifecycle groups and global populations, c) to review relationships between calcium intake, chronic disease risk, and fractures, and d) to discuss strategies to address diet deficiencies and lactose intolerance.01/2015; 4(1):1. DOI:10.7762/cnr.2015.4.1.1
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ABSTRACT: Background Considerable controversy exists regarding the association between dietary calcium intake and risk of mortality from cardiovascular disease and all causes. Therefore, we performed a meta-analysis of prospective cohort studies to examine the controversy.Methods We identified relevant studies by searching MEDLINE, Embase, and the Cochrane Library databases between 1 September 2013 and 30 December 2013. Reference lists of relevant articles were also reviewed. Observational prospective studies that reported relative risks and 95% confidence intervals for the association of calcium intake with cardiovascular and all-cause mortality were eligible. Study-specific relative risks were pooled using a random-effects model.ResultsIn this meta-analysis, 11 prospective studies with 12 independent cohorts, involving 757,304 participants, were eligible. There was evidence of a non-linear association between dietary calcium intake and risk of mortality from cardiovascular disease (P for non-linearity <0.01) and all causes (P for non-linearity <0.01). A dose-response analysis showed a U-shaped relationship between dietary calcium intake and cardiovascular mortality. Intakes that were lower and higher than around 800 mg/day were gradually associated with a higher risk of cardiovascular mortality. For all-cause mortality, we also observed a threshold effect at intakes around 900 mg/day. The risk of all-cause mortality did not decrease further at intakes above 900 mg/day.Conclusions This meta-analysis of prospective cohort studies suggests that dietary calcium intake is associated with cardiovascular mortality in a U-shaped manner and that high dietary calcium intake (>900 mg/day) is not associated with a decreased risk of all-cause mortality.BMC Medicine 09/2014; 12(1):158. DOI:10.1186/s12916-014-0158-6 · 7.28 Impact Factor