1. ^*University of Tennessee, Knoxville, Tennessee
2. ^†Mayo Clinic, Rochester, Minnesota

Correspondence: Michael B. Zemel, Department of Nutrition, University of Tennessee, 1215 W. Cumberland Avenue, Room 229, Knoxville, TN 37996-1920. E-mail: mzemel@utk.edu

^**The costs of publication of this article were defrayed, in part, by the payment of page charges. This article must, therefore, be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Received 10 September 2003; Accepted 4 February 2004.

Abstract

Objective: Increasing 1,25-dihydroxyvitamin D in response to low-calcium diets stimulates adipocyte Ca²⁺ influx and, as a consequence, stimulates lipogenesis, suppresses lipolysis, and increases lipid accumulation, whereas increasing dietary calcium inhibits these effects and markedly accelerates fat loss in mice subjected to caloric restriction. Our objective was to determine the effects of increasing dietary calcium in the face of caloric restriction in humans.

Research Methods and Procedures: We performed a randomized, placebo-controlled trial in 32 obese adults. Patients were maintained for 24 weeks on balanced deficit diets (500 kcal/d deficit) and randomized to a standard diet (400 to 500 mg of dietary calcium/d supplemented with placebo), a high-calcium diet (standard diet supplemented with 800 mg of calcium/d), or high-dairy diet (1200 to 1300 mg of dietary calcium/d supplemented with placebo).

Results: Patients assigned to the standard diet lost 6.4 2.5% of their body weight, which was increased by 26% (to 8.6 1.1%) on the high-calcium diet and 70% (to 10.9 1.6% of body weight) on the high-dairy diet (p < 0.01). Fat loss was similarly augmented by the high-calcium and high-dairy diets, by 38% and 64%, respectively (p < 0.01). Moreover, fat loss from the trunk region represented 19.0 7.9% of total fat loss on the low-calcium diet, and this fraction was increased to 50.1 6.4% and 66.2 3.0% on the high-calcium and high-dairy diets, respectively (p < 0.001).

Discussion: Increasing dietary calcium significantly augmented weight and fat loss secondary to caloric restriction and increased the percentage of fat lost from the trunk region, whereas dairy products exerted a substantially greater effect.