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. 2022 Apr 25;11(2):120-132.
doi: 10.7762/cnr.2022.11.2.120. eCollection 2022 Apr.

The Effect of Walnut (Juglans regia) Leaf Extract on Glycemic Control and Lipid Profile in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Atieh Mirzababaei  1 , Mojtaba Daneshvar  1 , Faezeh Abaj  1 , Elnaz Daneshzad  2 , Dorsa Hosseininasab  3 , Cain C T Clark  4 , Khadijeh Mirzaei  1
Affiliations

The Effect of Walnut (Juglans regia) Leaf Extract on Glycemic Control and Lipid Profile in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Atieh Mirzababaei et al. Clin Nutr Res. .

Abstract

Numerous clinical trials have examined the beneficial effects of Juglans regia leaf extract (JRLE) in patients with type 2 diabetes mellitus (T2DM); however, the results of these studies are inconsistent. Therefore, we conducted the current systematic review and meta-analysis to evaluate the effect of JRLE on glycemic control and lipid profile in T2DM patients. We searched online databases including PubMed, Scopus, EMBASE, and Web of Science for randomized controlled clinical trials that examined the effect of JRLE on glycemic and lipid indices in T2DM patients. Data were pooled using both fixed and random-effect models and weighted mean difference (WMD) was considered as the overall effect size. Of the total records, 4 eligible studies, with a total sample size of 195 subjects, were included. The meta-analysis revealed that JRLE supplementation significantly reduces fasting blood glucose (WMD, -18.04; 95% confidence interval [CI], -32.88 mg/dL, -3.21 mg/dL; p = 0.017) and significantly increases fasting insulin level (WMD, 1.93; 95% CI, 0.40 U/L, 3.45 U/L; p = 0.014). Although the overall effect of JRLE supplementation on hemoglobin A1c was not significant, a significant reduction was seen in studies with an intervention duration of > 8 weeks (WMD, -0.64; 95% CI, -1.16%, -0.11%; p = 0.018). Moreover, we also found no significant change in lipid parameters. Our findings revealed a beneficial effect of JRLE supplementation on glycemic indices in T2DM patients, but no significant improvement was found for lipid profile parameters.

Keywords: Diabetes mellitus; Glycemic control; HDL-cholesterol; Juglans; LDL-cholesterol; cholesterol.

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Conflict of interest statement

Conflict of Interest: The authors declare that they have no competing interests.

Figures

Figure 1
Figure 1. Flow diagram of study selection.
Figure 2
Figure 2. Forest plot for the effect of J. regia leaf extract on glycemic profiles: (A) fasting blood glucose, (B) insulin level, (C) postprandial glucose, and (D) hemoglobin A1c. Data are expressed as WMDs between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from the fixed-effects analysis.
WMD, weighted mean difference; CI, confidence interval.
Figure 3
Figure 3. Forest plot for the effect of J. regia leaf extract on lipid profile: (A) total cholesterol, (B) low-density lipoprotein cholesterol, (C) high-density lipoprotein cholesterol, and (D) triglyceride. Data are expressed as WMDs between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from the fixed-effects analysis.
WMD, weighted mean difference; CI, confidence interval.
Figure 4
Figure 4. Forest plot for the effect of J. regia leaf extract on liver enzymes: (A) alanine transaminase, (B) aspartate transaminase. Data are expressed as mean differences between intervention and control groups. Horizontal lines represent 95% CIs. Diamonds represent pooled estimates from the fixed-effects analysis.
WMD, weighted mean difference; CI, confidence interval.
See this image and copyright information in PMC

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