Meta-analysis rejects safety concerns over calcium supplementation for increasing coronary heart disease risk
Writing in the Journal of Bone and Mineral Research, the researchers noted that the effects were observed with or without vitamin D supplementation. However, the evidence is currently insufficient to support a lack of effect in men and younger women.
“The findings that calcium supplementation with or without vitamin D in elderly women did not increase coronary heart disease or all-cause mortality or the separate secondary outcomes of myocardial infarction, angina and acute coronary syndrome, and chronic coronary heart disease verified by clinical review, hospital record, or death certificate are reassuring,” wrote the researchers, led by Joshua Lewis from Sir Charles Gairdner Hospital Unit in Perth, Australia.
The other authors were affiliated with Aarhus University Hospital (Denmark), University of Sydney (Australia), Creighton University (USA), and the Fred Hutchinson Cancer Research Center (USA).
Bone health and heart health
Osteoporosis has been described as a silent killer, and recent data from the National Osteoporosis Foundation showed that approximately 9 million American adults currently have osteoporosis and another 48 million have low bone mass, placing them at increased risk.
An economic report from Frost & Sullivan and commissioned by the Council for Responsible Nutrition (CRN) recently found that supplements of calcium plus vitamin D for all US women with osteoporosis could provide healthcare cost savings of $1.08 billion per year.
Despite the clear benefits of calcium (and vitamin D) for bone health, papers published in journals such as JAMA, Heart, and the British Medical Journal found significant adverse cardiovascular effects related to excessive calcium intake in different populations, leading to concerns, and even condemnation of calcium supplements by some.
The plaques that form in diseased arteries are composed mostly of calcium, and some researchers have postulated that this is directly related to the rapid spiking of blood calcium levels following ingestion of the supplement.
The literature, however, is contradictory, with data published in the American Journal of Clinical Nutrition concluding that current evidence does not support the notion that calcium supplements increase the risk of heart disease in elderly women.
Sales of calcium supplements have been affected by the controversy. Dollar sales of calcium/calcium formula supplements declined 6.9% versus previous year’s sales, according to SPINS. There is positive news from the natural supermarkets, however, with growth of 1.5% year-on-year.
Lewis and his co-workers pooled data from 18 randomized clinical trials including 63,563 participants with 3,390 coronary heart disease (CHD) events and 4,157 deaths.
Data from five trials indicated that calcium supplementation did not increase the risk of CHD events, while data from 17 trials found no overall effect on all-cause mortality
In addition, no significant effects were found for heart attack risk, angina, or chronic CHD.
“Although food-derived calcium is the optimal source to achieve the recommended dietary intake (RDI) of calcium, in cases where this RDI cannot be reached from food sources alone the use of long-term calcium supplementation with vitamin D in older women should be considered, given the beneficial effects on falls, bone mineral density and fracture outcomes, and all-cause mortality,” wrote the researchers.
“However, given the uncertainty by patients and clinicians alike, further large well-designed randomized controlled trials of calcium supplementation with vitamin D that include bone and verified cardiovascular outcomes are urgently needed to address this issue.”
Industry sources have also noted that nutrition savvy dietitians would not recommend calcium in isolation, but in combination with other nutrients. One nutrient gaining more attention is vitamin K.
A recent paper published in Thrombosis and Haemostasis indicated that long-term supplementation with vitamin K2 may inhibit age-related stiffening of the artery walls in healthy postmenopausal women.
A daily 180 microgram dose of NattoPharma’s MenaQ7 vitamin K2 for three years was also associated with statistically significant improvement of vascular elasticity.
“This is the first study showing that long-term use of vitamin K2 in the form of MK-7 beneficially affects cardiovascular health,” said Cees Vermeer, Chief Innovation Officer at the R&D Group VitaK of the Maastricht University Holding (The Netherlands), and lead researcher on the study.
“The women taking the MenaQ7 vitamin K2 did not experience the typical age-related progression of arterial wall stiffening, and even made a statistically significant improvement of vascular elasticity, compared to the placebo group,” he added. “Our data demonstrated that a nutritional dose of vitamin K2 in fact improves cardiovascular outcomes.”
Source: Journal of Bone and Mineral Research
Volume 30, Issue 1, pages 165-175, doi: 10.1002/jbmr.2311
“The Effects of Calcium Supplementation on Verified Coronary Heart Disease Hospitalization and Death in Postmenopausal Women: A Collaborative Meta-Analysis of Randomized Controlled Trials”
Authors: J.R. Lewis, S. Radavelli-Bagatini, L. Rejnmark, et al.