Calcium does not impair iron status in practice

Abstract

I ncreased calcium intake with dairy products or supplements has been associated with weight loss in epidemiological studies, and animal experiments support a role of calcium in body weight regulation. An effect on energy balance by decreased fat absorption due to calcium soap formation in the intestine has been suggested, as well as an influence on energy metabolism at the cellular level. A systematic review and meta-analysis of randomized controlled trials with calcium supplements or increased provision of dairy products (at least 300 mg extra calcium per day) was published recently (1). Studies for 12 weeks or more in nonpregnant, non-lactating individuals aged at least 18 years were included. The meta-analysis was based on 13 studies, nine with calcium supplementation and four with increased intake of dairy products. No association was found between the increased consumption of calcium from supplements or dairy products and weight loss after adjustments for differences in baseline weights between the study and control groups. The overall conclusion was that calcium supplementation has no statistically significant association with a reduction in body weight. Although several studies, on both humans and experimental animals, indicate that dietary calcium may be involved in body weight regulation, it is too early to promote calcium supplements or dairy products as slimming agents. More properly powered intervention studies specifically aimed at testing this hypothesis are needed before any conclusions can be drawn in practice.