A study, “Dietary and Supplemental Calcium Intake and Cardiovascular Disease Mortality,” published in February in the Journal of the American Medical Association Internal Medicine (JAMA) found that calcium supplements, but not dietary calcium, is associated with an excess risk of cardiovascular disease (CVD) death in men but not in women. While the study spurred immediate responses from the Natural Products Association (NPA) and the Council for Responsible Nutrition (CRN), manufacturers and suppliers also offered their views:
• Dallas Clouatre, PhD, R&D consultant for California-based Jarrow Formulas, Inc.:
“Recently, there have been a number of research publications with contradictory findings regarding the impact of calcium intake, especially that from supplements, and morbidity and mortality rates. These reports up to this point have had more impact on doctors than on the general public. Nevertheless, they are a wild card for future calcium sales.
“Several studies, to the contrary, found supplementation to be generally harmful whether with or without vitamin D. (BMJ. 2013 Feb 12;346:f228; BMJ. 2011 Apr 19;342:d2040) Dueling analyses from major medical schools and research institutions disagree on these findings of hazard, some arguing that no such dangers exist. (Am J Clin Nutr. 2012 Dec;96(6):1274-80.) The safest position to date is that there is no consensus on the subject. (Am J Cardiovasc Drugs. 2012 Apr 1;12(2):105-16.) In general, dietary calcium sources and supplements, such as microcrystalline hydroxyapatite, that release calcium into the blood in the same manner as dietary sources are the safest alternatives.”
• Vladimir Badmaev, MD, PhD, head of R&D with Norwegian ingredient supplier NattoPharma ASA:
“The paradox of calcium as both hero and villain has been highlighted by the results of a 2013 JAMA published study by Xiao et al. Although the JAMA study indicates that supplemental calcium may adversely affect cardiovascular health in men only; other studies indicate that supplemental calcium intake puts women at cardiovascular risk as well, e.g. the WHI CaD Study reporting an increased risk of CVD in women allocated to a calcium supplementation group. In addition, use of calcium supplements with or without vitamin D was associated with a significant 24 percent increase in risk of coronary heart disease in a cohort of 10,555 Finnish women.
“These epidemiological findings suggest that guidelines for calcium supplements may have to be revised, and calcium and vitamin D supplements may need to be complemented with vitamin K2 intake for efficient delivery of calcium to ensure effective performance of the body’s physiological functions.”
“Vitamin K is critical for efficient metabolism of calcium in the body. Calcium is crucial for the maintenance of a strong skeletal system and teeth but also for nerve transmission, blood clotting, vascular tone, blood pressure, muscle contraction, enzyme activation, and hormone regulation. Sufficient dietary calcium may lower the risk of colorectal cancer and lower risk of cardiovascular disease due to lowering blood lipids and when taken in moderation it has a tendency to lower blood pressure. Calcium supplements, with or without vitamin D, have been widely used for the prevention and treatment of osteoporosis and general health support of an aging population. However, when nutritional vitamin K intake is low, the K-dependent proteins is unavailable in its active carboxylated form and uncontrolled mineralization of calcium in arterial walls has been shown to contribute to cardiovascular disease.
“In 2012, results of a three-year study by Vermeer et al demonstrated for the first time clinically statistically significant protection of the vertebrae and the hip (femoral neck) against osteoporosis—as well as cardiovascular deterioration. This represents the first clinical study showing that only a long-term (more than one year), supplemental vitamin K, especially menaquinone-7, improves bone mineral density and bone strength. This study was a double-blind randomized clinical trial (RCT) evaluating the results of a three-year regular intake of menaquinone-7 in a 180 mcg daily dose by a group of 244 healthy post-menopausal Dutch women, 55 to 65 years old, randomly assigned to receive daily either MenaQ7® or identical looking placebo capsules.
“Regarding bone health specifically, one of the most important findings from the study was that clinically relevant improvement became evident no sooner than after two and three years of MenaQ7® supplementation. This finding explains for the first time why shorter studies (e.g. 12 months or less) typically failed to show benefits of vitamin K on bone health and cardiovascular health.”