Influence of the Digested Products of Royal Jelly on Insulin Levels in KK-Ay Mice

Aspergillus niger protease digest of royal jelly (royal jelly peptides) was administered to KK-Ay diabetic mice for 35 days. Oral administration of a high dose (350 mg/kg) of royal jelly peptides suppressed increases in blood glucose levels similar to extract of guava leaves, an α-amylase inhibitor. This effect appears to be due to a decrease in food intake and subsequent reduction in body weight. In mice with free access to diet containing royal jelly peptides at 0.18 w/w%, no effect on blood glucose levels, blood triglyceride levels, food intake and body weight were found. However, an increase in blood insulin levels was observed. This suggests that royal jelly peptides may increase insulin levels without affecting blood glucose levels and food intake.