Calcium Essential to Limit Osteoporosis but Avoid Excess, Say Europeans

Becky McCall

October 19, 2017

Consuming just the right amount of calcium is a mainstay for general bone health in postmenopausal women, while an excessive amount shows no benefit and could possibly be harmful, says a new European Menopause and Andropause Society (EMAS) clinical guideline.

"It's important to keep a woman's bones healthy, but the amount of calcium taken should not be too high. Around 700 to 1000 mg per day is sufficient," said first author, Antonio Cano, MD, professor of obstetrics and gynecology, from the University of Valencia and INCLIVA, Valencia, Spain.

Summarizing the key clinical take-aways, he explained, "There are times when supplementation is important — for example, during adolescence and postmenopause — but only at the recommended amount and not in excess of this, because there is no benefit and there might be risk associated with this."

There has been uncertainty about the appropriate levels of calcium intake for postmenopausal women, and different societies have different recommendations, ranging from a daily intake of between 700 and 1200 mg. There is also conflicting evidence on the potential harms of excessive intake, with concerns about possible cardiovascular risk, dementia, or even, paradoxically, fracture.

Against this background, EMAS issued this new clinical guide to assist healthcare professionals when advising women regarding calcium intake for the prevention of postmenopausal osteoporosis. It was published online October 3, 2017 in Maturitas.

They stress these EMAS recommendations do not apply to women already receiving antiosteoporotic drugs, since their efficacy has been proven in clinical trials in which the participants were supplemented with calcium and vitamin D.

Postmenopausal Osteoporosis Increasing: 700–1000 mg of Calcium/Day Recommended

Osteoporotic fractures are an increasing problem in postmenopausal women, reflecting the aging population. Approximately 30% of all postmenopausal women in the United States and Europe have osteoporosis, and at least 40% of these women will suffer one or more fragility fractures, write the authors.

"Insufficient calcium accrual can lead to a suboptimal bone-mass peak and low bone mineralization, and this is an important factor influencing osteoporosis and fracture."

Dr Cano explained that despite effective pharmacological approaches that reduce fracture risk, in Europe, there is no relevant indication for use of these drugs in postmenopausal women.

"Prevention is very important, and in the US prevention is a recognized indication for drug use. However, this is not the case here," he told Medscape Medical News.

"We need to do something for postmenopausal women, who constitute a large population group. Hormone-replacement therapy is currently used, but there are side effects and its indication is restricted to hot flushes and symptoms of menopause," he stressed.

"We suggest lifestyle changes including physical activity and good nutrition. In this context calcium should be provided."

During the development of this guidance, the authors analyzed findings from systematic reviews, meta-analyses, and randomized controlled trials over a period of 10 years from 2007.

"The amount of calcium needed to fulfill the needs of postmenopausal women is approximately 700 to 1000 mg/day, and this has not been sufficiently stressed in existing guidelines," said Dr Cano, explaining the rationale behind the new guide.

Amount Should Be "Just Right": Excess Calcium Can Be Harmful

Dr Cano also highlighted the fact that studies indicate there is a tendency for general practitioners to prescribe calcium without checking the total amount the woman is consuming, echoing the "better-over-than-under" principle and recommending calcium supplements in all cases.

"One study showed that around half of women in some population groups are taking too much. We want to stress that women take enough, but not too much."

Excess calcium intake may increase cardiovascular risk due to the association between calcium and atherosclerosis. And "there are renal risks [increased calcium in the urine confers a subsequent increased risk for nephrolithiasis, for example], and a study in Sweden even suggests an increase in dementia, but more research is needed in this respect."

In the US, a 2016 joint clinical guideline from the National Osteoporosis Foundation (NOF) and the American Society for Preventive Cardiology (ASPC) stated that dietary and supplemental calcium are safe for cardiovascular health when consumed in recommended amounts — that is, the National Academy of Medicine's upper-intake limit of 2000 to 2500 mg/day (Institute of Medicine. Washington, DC: National Academies Press, 2011).

However, Dr Cano and coauthors of the new EMAS clinical guide say there are limitations to this evidence because cardiovascular disease has been only a secondary outcome in trials.

Dietary Calcium Preferable

The EMAS guide also stresses that calcium obtained from food is preferable to supplements because the calcium peaks in blood — which have been associated with deleterious health effects — are fewer when it is consumed as part of the diet, said Dr Cano.

Other concerns with supplementation are poor adherence and inappropriate supplementation.

However, in certain situations, for example, in vegan women who have calcium-poor diets, it is necessary to increase their calcium intake via supplementation.

"If they decline supplements, as long as they increase their vitamin D levels and/or physical activity, they should be able to balance their insufficiency," he highlighted.

Key EMAS Recommendations for Postmenopausal Women and Calcium Intake
  Summary recommendation
Calcium intake and osteoporosis risk Adequate intake of calcium as a mainstay in the prevention of postmenopausal osteoporosis remains a universal recommendation in guidelines.
Assess calcium intake Assess an individual's calcium intake and recommend supplementation if levels are insufficient.
Higher-than-recommended intake Warn women that higher-than-recommended calcium intake may be useless or possibly harmful.
Dietary calcium Dietary calcium intake may be advantageous, but strong evidence is lacking.
Physical activity and vitamin D Women who refuse supplements and cannot maintain a calcium-rich diet should be reassured that this is unlikely to adversely affect their fracture risk. Other measures, like physical activity and vitamin D supplements, may be beneficial for bone health.

US vs European Guidelines

Asked to contrast the US and European guidance, Dr Cano highlighted the key difference as being the threshold for the amount of calcium recommended.

As well as the joint guideline from the NOF and the ASPC, the US Institute of Medicine (IOM) Food and Nutrition Board, recommends 1200 mg of elemental calcium per day (Institute of Medicine. Washington, DC: National Academies Press, 2011), while a consensus statement issued in 1994 by the National Institutes of Health (NIH) recommended 1500 mg of elemental calcium per day obtained from dietary sources or supplements for postmenopausal women (Institute of Medicine. Washington, DC: National Academies Press, 1994). Meanwhile, a 2006 position statement of the North American Menopause Society says that the target calcium intake for most postmenopausal women is 1200 mg/day (Menopause. 2006;13:862-877).

Dr Cano said that in the United States a 300-mg higher ceiling for intake of calcium per day is recommended than is advised in Europe, but "this isn't so important, because the limit is wide. Problems really start at around 2000 mg or more."

Dr Cano is supported by a grant from the Instituto de Salud Carlos III Fondo de Investigación Sanitari, Ministerio de Sanidad y Consumo, Madrid, Spain, and the European Regional Development Fund, Instituto de Salud Carlos III. The authors declare no relevant financial relationships.

Maturitas. Published online October 3, 2017. Abstract

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