Almond supplementation on appetite measures, body weight, and body composition in adults: A systematic review and dose-response meta-analysis of 37 randomized controlled trials

BACKGROUND AND OBJECTIVE

Almond consumption has an inverse relationship with obesity and factors related to metabolic syndrome. However, the results of available clinical trials are inconsistent. Therefore, we analyzed the results of 37 randomized controlled trials (RCTs) and evaluated the association of almond consumption with subjective appetite scores and body compositions.

METHODS

Net changes in bodyweight, body mass index (BMI), waist circumference (WC), fat mass (FM), body fat percent, fat-free mass (FFM), waist-to-hip ratio (WHR), visceral adipose tissue (VAT), and subjective appetite scores were used to calculate the effect size, which was reported as a weighted mean differences (WMD) and 95% confidence interval (CI).

RESULTS

This meta-analysis was performed on 37 RCTs with 43 treatment arms. The certainty in the evidence was very low for appetite indices, body fat percent, FFM, VAT, and WHR, and moderate for other parameters as assessed by the GRADE evidence profiles. Pooled effect sizes indicated a significant reducing effect of almond consumption on body weight (WMD: -0.45 kg, 95% CI: -0.85, -0.05, p = 0.026), WC (WMD: -0.66 cm, 95% CI: -1.27, -0.04, p = 0.037), FM (WMD: -0.66 kg, 95% CI: -1.16, -0.17, p = 0.009), and hunger score (WMD: -1.15 mm, 95% CI: -1.98, -0.32, p = 0.006) compared with the control group. However, almond did not have a significant effect on BMI (WMD: -0.20 kg m-2, 95% CI: -0.46, 0.05, p = 0.122), body fat percent (WMD: -0.39%, 95% CI: -0.93, 0.14, p = 0.154), FFM (WMD: -0.06, 95% CI: -0.47, 0.34, p = 0.748), WHR (WMD: -0.04, 95% CI: -0.12, 0.02, p = 0.203), VAT (WMD: -0.33 cm, 95% CI: -0.99, 0.32), fullness (WMD: 0.46 mm, 95% CI: -0.95, 1.88), desire to eat (WMD: 0.98 mm, 95% CI: -4.13, 2.23), and prospective food consumption (WMD: 1.08 mm, 95% CI: -2.11, 4.28). Subgroup analyses indicated that consumption of ≥50 g almonds per day resulted in a significant and more favorable improvement in bodyweight, WC, FM, and hunger score. Body weight, WC, FM, body fat percent, and hunger scores were decreased significantly in the trials that lasted for ≥12 weeks and in the subjects with a BMI < 30 kg/m2. Furthermore, a significant reduction in body weight and WC was observed in those trials that used a nut-free diet as a control group, but not in those using snacks and other nuts. The results of our analysis suggest that almond consumption may significantly improve body composition indices and hunger scores when consumed at a dose of ≥50 g/day for ≥12 weeks by individuals with a BMI < 30 kg/m2.

CONCLUSION

However, further well-constructed randomized clinical trials are needed in order ascertain the outcome of our analysis.

Ginger intervention on body weight and body composition in adults: a GRADE-assessed systematic review and dose-response meta-analysis of 27 randomized controlled trials

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.

Dietary Antioxidant Capacity Indices are Negatively Correlated to LDL-Oxidation in Adults

INTRODUCTION

Former research studies have demonstrated controversial associations between dietary indices and oxidative stress biomarkers including oxidized low-density lipoprotein (ox-LDL) and malondialdehyde (MDA). So, in this cross-sectional study, we aimed to assess the association of dietary total antioxidant capacity (DTAC), oxidative balance score, and phytochemical index (PI) with ox-LDL/MDA in a healthy adult population of Shiraz, Iran.

METHODS

236 individuals participated in this cross-sectional study. DTAC, OBS, and PI were calculated using a 168-item food frequency questionnaire (FFQ), which was previously validated in Iran. We measured ox-LDL and MDA in blood samples of the participants using commercially existing kits. Crude and adjusted models of linear regression were used to evaluate the relation of dietary indices with ox-LDL and MDA.

RESULTS

There was a significant association between ox-LDL and DTAC in both crude (β = -1.55; 95% CI: -2.53, -0.58; P-trend = 0.002) and adjusted (β = -1.65 95% CI: -2.66, -0.64; P-trend = 0.001) models. Also, a negative association was observed between ox-LDL and PI in the crude (β = -1.26 95% CI: -2.33, -0.29; P-trend = 0.01) and adjusted (β = -1.36 95% CI: -2.38, -0.34; P-trend = 0.01) models.

CONCLUSION

Results of this study showed that DTAC and PI were inversely associated with ox-LDL as markers of lipid peroxidation. But no correlations were seen between MDA and dietary antioxidant indices.