Dietary calcium from dairy, body composition and glycaemic control in patients with type 2 diabetes pursuing an energy restricted diet: A parallel group randomised clinical trial

[Body composition, mineral metabolism, and endocrine function of adipose tissue: influence of a nutritional supplement of propolis]

Introduction

Introduction: propolis and its components influence lipid metabolism; however, its effect on body composition and mineral metabolism remains unknown. Objectives: to determine the effect of natural propolis supplementation on body composition, mineral metabolism, and the endocrine function of adipose tissue. Material and methods: twenty albino male Wistar rats (8 weeks old) were divided into two groups of 10 animals each. The rats were fed two different types of diet for 90 days: a standard diet for the control group (group C) and the same standard diet + 2 % propolis (group P). Thyroid hormones, ghrelin, leptin, adiponectin and insulin, non-esterified fatty acids (NEFA) in plasma, body composition (lean mass, fat mass and body water), and mineral deposition in target organs (spleen, brain, heart, lungs, testicles, kidneys and femur) were assessed. Results: thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4) did not show any differences after supplementation with propolis, while ghrelin and adiponectin decreased (p < 0.01 and p < 0.05, respectively) and insulin (p < 0.01), leptin (p < 0.05) and NEFA (p < 0.05) increased when 2 % propolis was supplied, while weight and body fat were reduced (p < 0.05) and lean mass increased. Lastly, the propolis supplement improves calcium deposition in the spleen, lungs, testes, and femur (p < 0.05). Conclusion: propolis supplementation of the diet (2 %) causes a decrease in the secretion of ghrelin and adiponectin, increasing the release of non-esterified fatty acids and the rate of insulin secretion. In addition, propolis supplementation induces an improvement in calcium deposition in target organs without affecting the rest of minerals, which improves body composition by inducing a reduction in weight and visceral adipose tissue, and improvement in lean mass.

Calcium Supplementation Alleviates High-Fat Diet-Induced Estrous Cycle Irregularity and Subfertility Associated with Concomitantly Enhanced Thermogenesis of Brown Adipose Tissue and Browning of White Adipose Tissue

Obesity has been demonstrated as a disruptor of female fertility. Our previous study showed the antiobesity effects of calcium on HFD-fed male mice. However, the role of calcium in alleviating reproductive dysfunction of HFD-fed female mice remains unclear. Here, we found that HFD led to estrus cycle irregularity (longer cycle duration and shorter estrus period) and subfertility (longer conception time, lower fertility index, and less implantations) in mice. However, the HFD-induced reproductive abnormality was alleviated by calcium supplementation. Additionally, calcium supplementation enhanced activation/thermogenesis of BAT and browning of WAT in HFD-fed mice. Consequently, the abnormality of energy metabolism and glucose homeostasis induced by HFD were improved by calcium supplementation, with elevated metabolic rates and core temperature. In conclusion, these data showed that calcium supplementation alleviated HFD-induced estrous cycle irregularity and subfertility associated with concomitantly enhanced BAT thermogenesis and WAT browning, suggesting the potential application of calcium in improving obesity-related reproductive disorders.

Anti-Obesity Effects of Dietary Calcium: The Evidence and Possible Mechanisms

Obesity is a serious health challenge worldwide and is associated with various comorbidities, including dyslipidemia, type 2 diabetes, and cardiovascular disease. Developing effective strategies to prevent obesity is therefore of paramount importance. One potential strategy to reduce obesity is to consume calcium, which has been implicated to be involved in reducing body weight/fat. In this review, we compile the evidence for the anti-obesity roles of calcium in cells, animals, and humans. In addition, we summarize the possible anti-obesity mechanisms of calcium, including regulation of (a) adipogenesis, (b) fat metabolism, (c) adipocyte (precursor) proliferation and apoptosis, (d) thermogenesis, (e) fat absorption and excretion, and (f) gut microbiota. Although the exact anti-obesity roles of calcium in different subjects and how calcium induces the proposed anti-obesity mechanisms need to be further investigated, the current evidence demonstrates the anti-obesity effects of calcium and suggests the potential application of dietary calcium for prevention of obesity.