Systematic Reviews
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Diabetes. Feb 15, 2019; 10(2): 96-113
Published online Feb 15, 2019. doi: 10.4239/wjd.v10.i2.96
Effectiveness of royal jelly supplementation in glycemic regulation: A systematic review
Kamel Omer, Maxwell J Gelkopf, Genevieve Newton
Kamel Omer, Maxwell J Gelkopf, Genevieve Newton, Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
Author contributions: Omer K and Newton G conceptualized research question and created search strategy; Omer K and Gelkopf MJ conducted full text inclusions and risk of bias assessments; Omer K and Newton G conducted GRADE assessment; Newton G reviewed manuscript throughout writing stage; Omer K conducted database search, data extraction and analysis, and manuscript preparation.
Conflict-of-interest statement: The authors declare no conflict of interest.
PRISMA 2009 Checklist statement: The authors have read the PRISMA 2009 Checklist, and the manuscript was prepared and revised according to the PRISMA 2009 checklist.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Genevieve Newton, BSc, MSc, PhD, Associate Professor, Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G2W1, Canada. newton@uoguelph.ca
Telephone: +1-519-8244120-56822 Fax: +1-519-7635902
Received: November 15, 2018
Peer-review started: November 15, 2018
First decision: November 29, 2018
Revised: January 29, 2019
Accepted: February 11, 2019
Article in press: February 12, 2019
Published online: February 15, 2019
Abstract
BACKGROUND

Royal jelly (RJ) has been observed to have therapeutic properties in diabetic individuals, including the reduction of high blood sugar. This systematic review synthesized existing evidence to investigate the effectiveness of RJ supplementation in managing measures of blood glucose.

AIM

To determine the effectiveness of RJ supplementation on glycemic responses in healthy and non-insulin dependent diabetic adults, as well as animal models of diabetes.

METHODS

This was a systematic review employing the PRISMA strategy. Peer-reviewed, published articles were extracted from several databases using key words related to target population, intervention and outcome and hand-selected for inclusion. Included articles proceeded to data extraction phase, where information on target parameters and effectiveness of treatment was summarized. Following this, the risk of bias for each included study was evaluated. Then, the long-term and immediate effectiveness of RJ supplementation in glycemic control were assessed using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) tool, which rates the quality of evidence.

RESULTS

Of 168 articles extracted from database searching, eighteen were included for analysis in this systematic review. Across the studies, studied populations, intervention styles and outcome measures were largely heterogeneous. Despite this, the results in studies indicate a general trend of positive effect of RJ in glycemic regulation in vitro and in vivo. Additionally, some dose-dependent glycemic effects were observed, along with some large effect sizes. The risk of bias for human and animal studies is generally low-unclear risk, although lack of blinding is a serious concern in both categories. Overall, as per the GRADE tool, the quality of evidence is low, and very low for long-term and immediate effectiveness of RJ, respectively. A major limitation affecting evidence quality is the heterogeneity among included studies. Fasting blood glucose and glucose clearance appear to be most affected by RJ supplementation.

CONCLUSION

Quality of evidence suggesting that RJ is an effective modulator of glycemic regulation is low for long-term effects of RJ, and very low for immediate effects.

Keywords: Royal jelly, Type 2 diabetes, Dietary supplement, Glycemic control, 10-hydroxy-trans-2-decenoic acid, Hyperglycemia, Adults, Animals

Core tip: Royal jelly (RJ) is a promising natural treatment to improve high blood glucose. Insulin sensitivity, fasting blood glucose levels, and rate of glucose clearance are among the glycemic parameters investigated in the current systematic review that are shown to approach normal levels due to regular RJ intake.