A Randomized, Double-Blind Comparison Study of Royal Jelly to Augment Vascular Endothelial Function in Healthy Volunteers

Exploring the Therapeutic Potential of Royal Jelly in Metabolic Disorders and Gastrointestinal Diseases

Metabolic disorders, encompassing diabetes mellitus, cardiovascular diseases, gastrointestinal disorders, etc., pose a substantial global health threat, with rising morbidity and mortality rates. Addressing these disorders is crucial, as conventional drugs often come with high costs and adverse effects. This review explores the potential of royal jelly (RJ), a natural bee product rich in bioactive components, as an alternative strategy for managing metabolic diseases. RJ exhibits diverse therapeutic properties, including antimicrobial, estrogen-like, anti-inflammatory, hypotensive, anticancer, and antioxidant effects. This review's focus is on investigating how RJ and its components impact conditions like diabetes mellitus, cardiovascular disease, and gastrointestinal illnesses. Evidence suggests that RJ serves as a complementary treatment for various health issues, notably demonstrating cholesterol- and glucose-lowering effects in diabetic rats. Specific RJ-derived metabolites, such as 10-hydroxy-2-decenoic acid (10-HDA), also known as the "Queen bee acid," show promise in reducing insulin resistance and hyperglycemia. Recent research highlights RJ's role in modulating immune responses, enhancing anti-inflammatory cytokines, and suppressing key inflammatory mediators. Despite these promising findings, further research is needed to comprehensively understand the mechanisms underlying RJ's therapeutic effects.

The effect of Royal jelly on liver enzymes and glycemic indices: A systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Royal jelly (RJ) may contribute to glycemic control and liver function through various mechanisms. The present study aimed to quantify the effect of RJ supplementation on these outcomes.

METHODS

A literature search of Web of Science, Scopus, and PubMed/Medline, was conducted for RCTs investigating the efficacy of RJ on plasma liver enzymes and glycemic indices. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated for net changes using a random-effects model.

RESULTS

Ten RCTs were selected for inclusion in this meta-analysis. Combined estimate of effect sizes for the impact of RJ on neither the plasma liver enzymes nor the glycemic indices were statistically significant. Subgroup analysis showed a significant reduction of serum FPG in trials with intervention duration ≥ 8 weeks (WMD: -4.28 mg/dl, 95% CI -7.41 to -1.14 mg/dl, p = 0.007), and those conducted in non-healthy populations (WMD: -4.28 mg/dl, 95% CI -7.41 to -1.14, p = 0.007).

CONCLUSION

RJ does not significantly affect liver function and glycemic profile of adult population. In trials with longer intervention and those conducted in non-healthy populations a significant reduction of serum FBG was observed. This meta-analysis should be repeated in the future, with more primary articles included, in order to provide conclusive results.

Royal jelly: a predictive, preventive and personalised strategy for novel treatment options in non-communicable diseases

Royal jelly (RJ) is a bee product produced by young adult worker bees, composed of water, proteins, carbohydrates and lipids, rich in bioactive components with therapeutic properties, such as free fatty acids, mainly 10-hydroxy-trans-2-decenoic acid (10-H2DA) and 10-hydroxydecanoic acid (10-HDA), and major royal jelly proteins (MRJPs), as well as flavonoids, most flavones and flavonols, hormones, vitamins and minerals. In vitro, non-clinical and clinical studies have confirmed its vital role as an antioxidant and anti-inflammatory. This narrative review discusses the possible effects of royal jelly on preventing common complications of non-communicable diseases (NCDs), such as inflammation, oxidative stress and intestinal dysbiosis, from the viewpoint of predictive, preventive and personalised medicine (PPPM/3PM). It is concluded that RJ, predictively, can be used as a non-pharmacological therapy to prevent and mitigate complications related to NCDs, and the treatment must be personalised.

The effects of royal jelly supplementation on anthropometric indices: a GRADE-assessed systematic review and dose-response meta-analysis of randomized controlled trials

Inconsistent data are available about the effect of royal jelly supplementation on anthropometric indices in humans. This systematic review and meta-analysis was done to summarize data from available randomized controlled trials (RCTs) on the effect of royal jelly supplementation on anthropometric indices such as body weight (BW), body mass index (BMI), and fat mass (FM) in adults. We systematically searched Embase, PubMed, Web of Science, and Scopus databases up to March 2023. All RCTs assessing the effect of royal jelly on anthropometric indices were included. Data were pooled using the random-effects method and were expressed as weighted mean difference (WMD) and 95% confidence intervals (CIs). Sensitivity and subgroup analyses were also performed. Out of 1,492 records, 10 studies that enrolled 512 participants were included. There was no significant effect on BW (WMD: -0.29 kg, 95% CI: -1.24, 0.65, p = 0.543), BMI (WMD: 0.11 kg/m2, 95% CI: -0.29, 0.52, p = 0.583), and FM (WMD: 0.02%, 95% CI: -0.41, 0.46, p = 0.84). However, we observed a reduction in BW and BMI following royal jelly intake in subgroup of royal jelly dosage <3,000 mg/day. Although the royal jelly supplementation significantly reduced BW and BMI at the dosages <3,000 mg/day, until additional trials have been conducted to assess the effects on obesity measures, it is best to prescribe royal jelly with caution.

Royal Jelly Increases Hematopoietic Stem Cells in Peripheral Blood: A Double-Blind, Placebo-Controlled, Randomized Trial in Healthy Subjects

Objectives

Royal jelly (RJ), produced by honeybees, influences stem cell functions, such as pluripotency maintenance of mouse embryonic stem cells and prevention of aging-related muscle stem cell functional deterioration. Thus, we hypothesized that RJ administration has various health-promoting effects based on stem cells. However, its effects are unknown in humans. In this study, we have attempted for the first time to clarify whether the administration of RJ in humans affects stem cells.

Materials and Methods

This randomized, double-blind, placebo-controlled study was performed on healthy subjects (n = 90) who received protease-treated RJ at a dose of 1200 mg/day or placebo daily for four weeks. Also, the participants with a low number of hematopoietic stem cells (HSCs) in peripheral blood were preferentially selected. HSC counts, endothelial progenitor cell (EPC) counts, blood cell counts in peripheral blood, cytokines in serum, and physical conditions were evaluated. Results and Conclusion. Eligible data from 86 subjects (placebo: 42, RJ: 44) who completed the study were analyzed. There were no significant differences between the two groups regarding the changes in peripheral HSC count (p=0.103), while diastolic blood pressure showed a significant improvement in the RJ group compared to that in the placebo group (p=0.032). The subgroup analysis excluded 14 subjects who complained of cold symptoms at baseline or within five days of the four-week study. The changes in the HSC populations were significantly higher in the RJ group than those in the placebo group (p=0.042). No adverse effects were observed in any of the groups. These results suggest that RJ administration affected the peripheral HSC count and may influence stem cell functions. Further research is needed to reveal the various health-promoting benefits of RJ based on stem cells.