Nutritional Advice El Mondo
Objectives:
The potential glucose-lowering effects of pomegranate have been reported in animal and observational studies, but intervention studies in humans have generated mixed results. Therefore, this review article (meta-analysis) has been conducted.
What are the effects of pomegranate supplementation on measures of glucose control, insulin levels and insulin sensitivity in humans?
Study design:
This review article included 16 RCTs with 538 subjects. 14 trials adopted parallel study designs and the 2 remaining trials used crossover designs.
The total number of subjects included in each study ranged from 14 to 74 subjects.
The mean age of participants in each trial ranged from 30 to 70 years, with differing age ranges in most studies.
11 studies used pomegranate juice as a supplement (the dosage ranged from 120 to 500 ml/day).
2 studies used pomegranate seed oil as treatments (the dosage ranged from 400 to 2000 mg/day).
3 studies utilized pomegranate extract as the intervention (the dosage ranged from 710 to 1420 mg/day).
The duration of the pomegranate intervention varied from 1 to 12 weeks (median: 5.5 weeks).
Overall, significant heterogeneity was detected for FBI and HOMA-IR, but subgroup analysis could not identify factors significantly influencing these parameters.
No significant publication bias was found.
Results and conclusions:
The investigators found that pomegranate did not significantly affect the measures of:
-FBG (fasting blood glucose) [WMD = -0.6 mg/dL, 95% CI = -2.79 to 1.58, p = 0.59, I2 = 0%];
-FBI (fasting blood insulin) [WMD = 0.29 μIU/mL, 95% CI = -1.16 to 1.75, p = 0.70, I2 = 60.4%];
-HOMA-IR (homeostatic model assessment of insulin resistance) [WMD = -0.04, 95% CI = -0.53 to 0.46, p = 0.88, I2 = 59.8%] or;
-HbA1c (glycated haemoglobin) [WMD = -0.11%, 95% CI = -0.39 to 0.18, p = 0.46, I2 = 0%].
These results were robust in sensitivity analysis.
The investigators found meta-regression analysis showed that the factor (dose of pomegranate juice supplementation) was not associated with the treatment effects on FBG level [coefficient = -0.006, 95% CI = -0.023 to 0.011, p = 0.46].
The investigators found no significant difference in the FBG-lowering effect between trials that were conducted in subjects with cardiovascular disease risk [WMD = 0.30 mg/dL, 95% CI = -2.36 to 2.97, p = 0.82] and those that were conducted in healthy individuals [WMD = -2.53 mg/dL, 95% CI = -6.36 to 1.30, p = 0.19].
The investigators found no statistically significant differences in the pooled effects of pomegranate on FBG in the subgroups stratified by study designs, intervention durations, types of intervention, baseline BMI and baseline FBG levels (FBG levels at the beginning of the studie).
The investigators concluded pomegranate supplements have no favourable effect on improvements in glucose and insulin metabolism. The current evidence suggests that daily pomegranate supplementation is not recommended as a potential therapeutic strategy in glycemic management. Further large-scale RCTs with longer duration are required to confirm these results.
Original title:
Lack of efficacy of pomegranate supplementation for glucose management, insulin levels and sensitivity: evidence from a systematic review and meta-analysis by Huang H, Liao D, […], Zhu Y.
Link:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5629805/
Additional information of El Mondo:
Find more information/studies on fruit consumption and diabetes right here.