Discussion
Based on our literature review, this is the first report about the effects of royal jelly supplementation on body weight and dietary intake in diabetic patients. In contrast to placebo group, royal jelly supplementation significantly decreased the mean body weight.
Different doses (500 mg or 1 or 2 g) of royal jelly supplementation in male swimmers, 5 days a week for 4 weeks did not decrease body weight, BMI and body fat mass [20]. But royal jelly supplementation in young football players led to significant increase of body weight and muscle component, and significant decrease of fat component after 8 weeks [19]. We could not compare our findings with the results of previous studies because their studies had been carried out in sportsmen and they emphasized on body composition, however observed positive effects of royal jelly supplementation on weight managements in studies in vivo and in viter may be due to increasing oxygen metabolism, respiration and oxidative phosphorylation [17] , furthermore 10H2DA of royal jelly activated TRPA1 (Transient receptor potential ankyrin 1) and TRPV1 (vanilloid1) which inducing thermogenesis and energy expenditure [16] and inhibiting pancreatic lipase activity consequently decreasing fat absorption from intestine [15] .
The observed body weight reduction in supplemented group can be justified by aforementioned mechanisms, since in the present study the mean daily total energy intake decreased significantly in supplemented group (P< 0/05), weight reduction may be due to decrease in mean daily total energy intake, however, other mechanisms such as appetite suppression may be involved in weight control in the supplemented group.
In conclusion, our findings revealed that royal jelly supplementation led to significant mean daily total energy intake and body weight reduction. Although, based on the results of the present study, supplementation with royal jelly may be beneficial in weight management for diabetic patients; further studies are needed to achieve precise results.