SUPLEMENTACJA SOLAMI WAPNIA – BEZPIECZNA CZY NIE?

Wtórna analiza badań zaplanowanych dla oceny oddziaływania węglanu wapnia, z lub bez witaminy D na częstość złamań kości (w tym dużych prospektywnych prób klinicznych CAIFOS, RECORD, WHI) nie wykazała wpływu suplementacji wapnia na CVD. Badania ujawniły, że przyjmowanie wapnia w dawce 1000-1200 mg/d nie wywiera negatywnego wpływu na chorobę niedokrwienną serca (CHD), zawał serca (MI), niewydolność krążenia, zwapnienie naczyń wieńcowych, udar oraz śmiertelność.

L20

Calcium supplementation – safe or not?

Tałałaj M.

Department of Family Medicine, Internal and Metabolic Bone Diseases

Postgraduate Medical Education Centre, Warsaw

Keywords: calcium, kidney stones, cardio-vascular diseases

         It was suggested that supplementation with calcium salts can increase the risk of formation of kidney stones composed of calcium oxalate and influence the risk of cardiovascular diseases (CVD). In healthy individuals a diet with normal calcium intake of 1000-1200 mg daily is associated with a reduction in kidney stone formation of approximately 50% as compared with a diet containing 400-600 mg calcium daily. It was shown that additional calcium supplementation has not resulted an increased risk of kidney stones unless total calcium intake exceeds 2000 mg/d. Calcium salts should be taken together with meals to avoid a rise in urine calcium excretion without any advantages of intestinal oxalate binding.

Secondary analyses of studies primarily designed to examine the influence of calcium carbonate, with or without vitamin D, on fracture incidence (including large prospective trials CAIFOS, RECORD, WHI) showed no significant effect of calcium supplement on CVD. The studies revealed that calcium supplement of 1000-1200 mg/d exerted no adverse effects on coronary heart disease (CHD), myocardial infarction (MI), heart failure, coronary artery calcification, stroke and mortality.

Post-hoc analyses of other prospective studies showed, however, that individuals using calcium supplements can be characterized by increased risk of CHD and MI. Meta-analyses published in the years 2010 and 2011 suggested that use of calcium supplements is accompanied by an 30% increased risk of MI in people with dietary calcium intake >800 mg/d. Increased mortality and incidence of MI can be associated with transient borderline hypercalcemia observed in persons taking calcium supplement of ≥1 g on an empty stomach. On the other hand it was shown that calcium supplement of 1000-1500 mg/d reduces systolic blood pressure in hypertensive patients, increases HDL and decreases LDL cholesterol levels as well as decreases serum phosphate concentration and platelets aggregation that can be protective for CVD.

The results of above mentioned studies should be interpreted with caution as they were not designed with cardiovascular events as primary outcomes. The meta-analyses included data on MI that were in large proportion self-reported, and none of the studies individually found significant adverse effects of calcium supplements on risk of MI.

Benefits of calcium supplement, especially given with vitamin D, seem to outweigh the risks of CVD. It has been calculated that 210-240 patients needed to be treated with calcium salts for 4-5 years to result in 1 MI while treatment of 74 patients at the age of ≥50 years is able to prevent 1 non-vertebral fracture and treatment of 109 patients prevents 1 hip fracture. It is recommended to assess dietary calcium intake of individual patient and prescribe additional calcium supplements only to patients with calcium intake <800 mg/d aiming for total daily calcium intake of 1000-1200 mg/d. Supplements should be taken together with meals to avoid hypercalcemia.