Spirulina supplementation and anthropometric indices: A systematic review and meta-analysis of controlled clinical trials.

Obesity and overweight are associated with the burden of chronic diseases. The aim of the present meta-analysis is to determine the efficacy of spirulina in reducing of obesity indices. PubMed, Web of Science, Scopus, EMBASE and Cochrane library databases were searched up to November 2019. Randomized controlled trials comparing spirulina supplementation with a placebo or no treatment for anthropometric indices were included. Meta-analysis was performed using random-effects model. Subgroup analysis and meta-regression were carried out. Publication bias was evaluated using standard methods. Spirulina had ameliorative effects on weight (WMD = -1.85 Kg; 95% CI: -2.44, -1.26; p < .001; I2 = 82.4%, p < .001), and waist circumference (WMD = -1.09 cm; 95% CI: -2.16, -0.01; p = .046; I2 = 0.0%, p = .757) while no significant effect was shown on body mass index, even after sensitivity analysis (SMD = -0.53 Kg/m2 ; 95% CI: -1.25, 0.19; p = .149; I2 = 92.9%, p < .001); however, spirulina was effective in studies lasted for at least 12 weeks (SMD = -1.25 Kg/m2 ; 95% CI: -2.21, -0.28; p = .011; I2 = 90.8%, p < .001). Spirulina supplementation exerts beneficial effects on weight and waist circumference. The ameliorative effect of spirulina on body mass index was revealed in longer duration of supplementation.

Effects of Sleeve Gastrectomy on Bone Marrow Adipose Tissue in Adolescents and Young Adults with Obesity.

CONTEXT: Sleeve gastrectomy (SG), the most common metabolic and bariatric surgery in adolescents, is associated with bone loss. Marrow adipose tissue (MAT) is a dynamic endocrine organ that responds to changes in nutrition and might serve as a novel biomarker for bone health. Two types of MAT have been described, which differ in anatomic location-proximal regulated MAT vs distal constitutive MAT. OBJECTIVE: To determine the effects of SG on volumetric bone mineral density (vBMD) and MAT in adolescents with obesity. We hypothesized that SG would lead to a decrease in vBMD and differential changes in MAT. DESIGN: 12-month prospective study in 52 adolescents with moderate-to-severe obesity (38 female; mean age:17.5 ±â€…2.2 years; mean BMI 45.2 ±â€…7.0 kg/m2), comprising 26 subjects before and after SG and 26 nonsurgical controls. MAIN OUTCOME MEASURES: Lumbar vBMD by quantitative computed tomography; MAT of the lumbar spine, femur and tibia by proton magnetic resonance spectroscopy; abdominal fat and thigh muscle by magnetic resonance imaging. RESULTS: Adolescents lost 34.1 ±â€…13.1 kg after SG vs 0.3 ±â€…8.4 kg in the control group (P < 0.001). Lumbar vBMD decreased in the SG group (P = 0.04) and this change was associated with a reduction in weight and muscle area (P < 0.05) and an increase in lumbar MAT (P = 0.0002). MAT of the femur and tibia decreased after SG vs controls (P < 0.05); however, the differences were no longer significant after controlling for change in weight. CONCLUSION: SG in adolescents decreased lumbar vBMD associated with an increase in lumbar MAT and decrease in extremity MAT. This demonstrates differential changes of regulated MAT in the lumbar spine and constitutive MAT in the distal skeleton in adolescents in response to SG.

Racial differences in lumbar marrow adipose tissue and volumetric bone mineral density in adolescents and young adults with obesity.

BACKGROUND: Areal bone mineral density (BMD) of the lumbar spine by DXA is greater in Black compared to White adolescents. Bone strength is determined not only by BMD but also its microenvironment, and marrow adipose tissue (MAT) has been shown to be an important determinant of skeletal integrity, independent of BMD. Racial differences in volumetric BMD (vBMD) and MAT in adolescents and young adults with obesity are unknown. OBJECTIVE: To assess racial differences in lumbar vBMD and MAT in Black and White adolescents and young adults with obesity and to assess body composition determinants of bone parameters. We hypothesized that Blacks will have higher vBMD and lower MAT of the lumbar spine compared to Whites. METHODS: The study group comprised 77 adolescents/young adults, 25 Black and 52 White, (mean age 18.2 ± 2.5 years, range 13 to 24 years) with moderate to severe obesity (mean body mass index (BMI) 46.2 ± 7.3 kg/m2, range 35.5 to 69.7 kg/m2). Groups were similar in age, BMI, and sex distribution (p > 0.84). Subjects underwent QCT of the lumbar spine (L1-L2) for assessment of vBMD with the use of a calibration phantom and 1H-MRS/MRI for quantification of lumbar MAT content (L1-L2) and abdominal fat and thigh muscle mass. Groups were compared by Student's t-test or Wilcoxon test. Correlation analysis was performed to assess associations between bone parameters and body composition. RESULTS: Black adolescents/young adults with obesity had higher vBMD compared to Whites (p < 0.0001), while there was no significant difference in lumbar MAT (p = 0.64). There were also no significant differences in body composition measures between groups (p ≥ 0.28). An inverse association between MAT and vBMD was observed in Whites (r = -0.47, P = 0.001) but not in Blacks (p = 0.6). There were no significant associations between body composition measures and bone parameters (p > 0.1). CONCLUSION: There are racial differences in lumbar vBMD in adolescents and young adults with moderate to severe obesity, with Blacks having higher vBMD than Whites, while there were no differences in MAT content. The known inverse association between BMD and MAT was only observed in Whites but not in Blacks, suggesting possible racial differences in stem cell differentiation into the bone and fat lineages.