The Calcium Supplement Controversy: Now What?

Abstract

F or decades there has been a consistent public health message about the use of calcium supplements in healthy adults: they prevent fracture and have no serious side effects. Although there is disagreement about the populations that are most likely to benefit and the magnitude of antifracture benefits, the best evidence pooled from multiple placebo-controlled trials suggests that supplementation with calcium plus vitamin D reduces fracture risk about 12%. (1) Some populations, such as the institutionalized elderly and those with inadequate dietary intake, may benefit from supplements to a greater degree than independent-living individuals with adequate calcium intake. The potential nonskeletal benefits of calcium supplementation remain controversial. (2) In addition to mild and often self-limited gastrointestinal intolerance, the most important confirmed side effect of supplementation is a 17% increase in nephrolithiasis. (3) The calcium supplement landscape, however, has changed considerably since the publication of two meta-analyses by Bolland and colleagues in 2010 (4) and 2011, (5) concluding that calcium supplements increase the risk of both coronary and cerebrovascular events. The first meta-analysis pooled 15 placebo-controlled trials of calcium supplements without vitamin D and found a statistically significant 31% increased risk of myocardial infarction (p ¼ 0.04) and a nonsignificant 20% increased risk of stroke (p ¼ 0.11) among calcium-treated individuals. (4) The study received considerable attention in the lay press, but was also criticized for excluding calcium plus vitamin D trials, inconsistent validation of cardiovascular endpoints, and the lack of a dose-response. In fact, analyses stratified on baseline calcium intake revealed significant supplement-related increases in myocardial infarction among those with higher pretreatment dietary calcium intake (above the median of 805 mg/d) but not among those with lower pretreatment calcium intake (interaction p ¼ 0.01).A follow-up meta-analysis by Bolland and colleagues 5 addressed at least some of these criticisms by including calcium plus vitamin D trials, and the results were similar: after pooling eight placebo-controlled trials, randomization to calcium alone or calcium plus vitamin D was associated with a statistically significant 24% increase in myocardial infarction (p ¼ 0.004) and a nonsignificant 15% increase in stroke (p ¼ 0.06). Although Bolland and colleagues included the Women's Health Initiative (WHI) Calcium Plus Vitamin D Supplementation Trial, which rigorously adjudicated thousands of cardiovascular outcomes and had previously reported no increase in vascular events among the calcium plus D group, (6) in their second meta-analysis Bolland and colleagues (5) excluded the 46% of WHI participants taking personal calcium supplements at baseline. The rationale offered for excluding women taking personal calcium supplements was that it allowed a pure comparison of supplement use versus no supplement use. Unfortunately, analysis of a subset...

Increase in the Serum Parathyroid Hormone Level During a Bisphosphonate Drug Holiday

“…[22] When calcium intake from dietary and/or supplemental sources is insufficient, compensatory loss of calcium from the bone occurs. [23] The calcium concentration in extracellular fluid is tightly maintained within a narrow range.…”

“…[2] However, calcium supplements have been reported to increase the risk of cardiovascular events and stroke,[10,11,12,26] although a causal relationship between calcium supplementation and cardiovascular events remains inconsistent and inconclusive. [22] It is now generally recommended that our calcium requirement should be obtained from dietary source, rather than from supplemental source. [26,27,28] Some patients, therefore, do not take enough calcium supplements during the bisphosphonate drug holiday.…”

Metals in plasma of nonagenarians and centenarians living in a key area of longevity

“…Anyway, the safety of Ca supplementation still remains an important clinical question, because Ca supplements could modestly increase the risk of nephrolithiasis and may cause mild gastrointestinal symptoms. For these reasons, clinicians reserve Ca supplementation only for people who are unable or unwilling to achieve adequate Ca dietary intake (Bauer, 2014). The hypocalcemia is diagnosed by finding of a serum Ca level lower than ca.…”

“…In this context, an adequate Ca and vitamin D supplementation can reduce the bone fracture risk in older adults of the 12%. On the other hand, Ca supplements modestly increase the risk of nephrolithiasis and may cause mild gastrointestinal symptoms (Bauer, 2014). The Co is contained in the vitamin B12 which plays an important role in the functioning of the brain and nervous system, in the production of red blood cells and prevention of anemia, and in the metabolism of proteins, carbohydrates and fats (Simonsen et al, 2012).…”

Micronutrient Needs of the Elderly

“…The American Society for Bone and Mineral Research continues to recommend combination supplementation of calcium and vitamin D but recognizes that increased dietary calcium is preferred over supplements. Although the controversy remains unsettled and continued research is needed, calcium supplementation should be considered in the institutionalized elderly and those who are unable able to achieve the recommended level of intake through dietary means alone 92 …”