RESUMO
CONTEXT: Ginger consumption may have an inverse relationship with obesity and metabolic syndrome parameters; however, clinical trials have reported contradictory results. OBJECTIVE: To systematically review and analyze randomized controlled trials (RCTs) assessing the effects of ginger on body weight and body composition parameters. METHODS: Databases were searched for appropriate articles up to August 20, 2022. All selected RCTs investigated the impact of ginger on glycemic indices in adults. A random effects model was used to conduct a meta-analysis, and heterogeneity was assessed using the I2 statistic. Net changes in body weight, body mass index (BMI), waist circumference (WC), and percent body fat were used to calculate the effect size, which was reported as a weighted mean difference (WMD) and 95% confidence intervals (CIs). The risk of bias was assessed. RESULTS: A total of 27 RCTs involving 1309 participants were included. The certainty in the evidence was very low for WC and BMI, and low for body weight and percent body fat as assessed by the GRADE evidence profiles. The meta-analysis showed a significant association between ginger supplementation and a reduction in body weight (WMD, -1.52 kg; 95%CI, -2.37, -0.66; P < 0.001), BMI (WMD, -0.58 kg/m2; 95%CI, -0.87, -0.30; P < 0.001), WC (WMD, -1.04 cm; 95%CI: -1.93, -0.15; P = 0.021), and percent body fat consumption (WMD, -0.87%; 95%CI, -1.71, -0.03; P = 0.042). The results of the nonlinear dose-response analysis showed a significant association between the ginger dose with body weight (Pnonlinearity = 0.019) and WC (Pnonlinearity = 0.042). The effective dose of ginger intervention for body mass reduction was determined to be 2 g/d in dose-response analysis. The duration of ginger intervention had a significant nonlinear relationship with body weight (Pnonlinearity = 0.028) with an effective duration of longer than 8 weeks. CONCLUSIONS: Our findings provide evidence that ginger consumption may significantly affect body composition parameters nonlinearly. More, well-constructed RCTs are needed.
RESUMO
OBJECTIVE: This study aimed to investigate the impact of Mentha arvensis on a rat model of polycystic ovary syndrome (PCOS). METHODS: The PCOS rat model was made by the daily subcutaneous injection of testosterone enanthate (250mg/kg) for 21 days. Thirty rats were divided into five groups, including a healthy control group and four PCOS groups treated with various concentrations of hydroalcoholic extract of Mentha arvensis (0, 50, 100 and 200mg/kg). LH and FSH were measured in the blood. The ovaries were used for histological investigation, Cyp17 and Ptgs2 genes expression and total antioxidant capacity. RESULTS: Our results indicated that the level of LH and FSH hormones in treated PCOS rats with various concentrations of M. arvensis were reduced in comparison with the untreated PCOS group (p>0.01). Mentha arvensis in the highest concentration (200mg/kg) decreased the number of cysts in this group in comparison with the untreated PCOS group (p<0.01). The expression of Cyp17 and Ptgs2 genes in the treated group with the highest concentration of hydroalcoholic extract were decreased in comparison with the untreated PCOS group (p<0.05). Moreover, the antioxidant capacity in the rats receiving Mentha arvensis hydroalcoholic extract was significantly increased in comparison with that from the untreated PCOS rats (p<0.05). CONCLUSIONS: For the first time, Mentha arvensis hydroalcoholic extract proved to reduce some polycystic ovary syndrome symptoms. In the present experiment, a dose of 200mg/kg of Mentha arvensis hydroalcoholic extract was regarded as the most efficient dose.
