Overweight adolescents may not benefit from increased calcium intake

Increased calcium consumption seems not to be associated with modifying body fat and body weight in children and adults, according to a new US study.

In the randomized controlled trial, 42 overweight and obese, but otherwise healthy adolescents aged 12–15 years received a strictly controlled diet for six weeks (1). All participants had a calcium intake of 756 mg Ca/day during the control period and 1400 mg Ca/day during the intervention period. During the intervention period, half of the group of adolescents was randomly assigned to receive additional calcium from a calcium carbonate (CaCO3) supplement while the other half received it from dairy calcium. Body mass index, fecal fat excretion, energy balance, and serum parathyroid hormone (PTH) concentrations were determined daily. The study results showed that the doubling of calcium intake, whether given as dairy calcium or as CaCO3, did not improve body weight or composition in the overweight adolescents.

The researchers concluded that under conditions when the energy intake is controlled and not reduced for weight loss, dietary calcium does not influence the energy balance in adolescents. Putative mechanisms for this potential effect – including the regulation of PTH release, fecal fat excretion, and fat oxidation – did not lead to a negative energy or fat balance. The evidence for a benefit of dietary calcium or dairy on body weight, suggested in earlier trials (2-4), would be either a false positive because of an uncontrolled energy intake or because they act as an appetite suppressant in free-living populations. Future research would be necessary to determine whether a negative fat balance could be induced with higher calcium intakes than those studied here and on energy-reducing diets.

1. Weaver C. M. et al. Calcium, dairy products, and energy balance in overweight adolescents: a controlled trial. Am J Clin Nutr. 2011; 94(5):1163–1170.
   
   
2. Van Loan M. The role of dairy foods and dietary calcium in weight management. J Am Coll Nutr. 2009; 28:120–129.
   
   
3. Astrup A. et al. Dairy beverages and energy balance. Physiol Behav. 2010; 100:67–75.
   
   
4. Christensen R. et al. Effect of calcium from dairy and dietary supplements on faecal fat excretion: a meta-analysis of randomized controlled trials. Obes Rev. 2009; 10:475–486.