The effect of meal frequency on serum immunoglobulin profile and insulin in rat

Background: Although consumption of three or less than three meals per day (gorging regimen) is usual in some communities, in western population there is an inclination towards many small meals a day (nibbling regimen). Up to now the effects of meal frequency on serum immunoglobulins have not been investigated in laboratory animals. There is also some controversy information about the effect of meal frequency on serum insulin in human and animal studies. The aim of present study was to investigate, the effects of meal frequency on immunoglobulin profile in rat. The effect of meal frequency on serum insulin was also surveyed. Material and methods: In this experimental study, thirty female Wister rats aged 11 weeks (210 ±15 g), after 10 days of acclimation period, were weighed and randomly assigned into two equal groups. They were fed the same food as eight meals at 2-hours intervals starting from 6 p.m. (nibbling group) or as two meals at 9 p.m. and 6 a.m. (gorging group) for 60 days. Blood samples were taken before and after intervention. ELLISA method was used to measure insulin and immunoglobulins in serum. All values were expressed as Mean±SD using Student’s t-test based comparisons. The research project was reviewed and approved by the Medical Ethics Committee of Tabriz University of Medical Sciences. Results: Diet regimens caused a non-significant reduction (P>0.05) in the serum insulin and IgA levels after sixty days of intervention. Although serum insulin level in the two regimens was non-significantly decreased, but the percentage of decrease in nibbling regimen was more than gorging one (-5.3% vs. –2.3%). Serum IgM and IgG levels in the two regimens were significantly increased (P0.05) between the two regimens before and after the intervention. Although, in both groups, serum IgM and IgG levels were significantly increased, but the percentage of increase was more in nibbling regimen than gorging one (56% vs. 38% and 37% vs. 28.7% for IgM & IgG respectively). The food and water intakes were non-significantly (P>0.05) lowered in the gorging group compared with the nibbling one. Conclusion: Although there is not a significant difference between the nibbling and gorging dietary regimens regarding the serum IgM , IgG, IgA and insulin but, nibbling regimen affects serum insulin, IgM and IgG more than gorging one in rat. More research on human and animal subjects is advised.