White beans (Phaseolus vulgaris L.) in diet reduces hypothalamic pro-inflammatory cytokines improving insulin resistance in small litter grown rats

Abstract

In the present study we were interested in studying the effect of white beans (Phaseolus vulgaris L.) as diet supplementation on glucose-insulin and metabolic homeostasis in early overfeeding rats. Small litter (SL) was adjusted to 3 pups on post-natal day 3, while normal litter (NL) was kept with 8 pups. The milk collection and milk intake were performed, and the rat-offspring when weaned (at 22 days old), were fed a standard (NL-SD and SL-SD groups) or a white bean (2.5 % w/w) supplemented diet (NL-WB and SL-WB groups). Body weight, food and water intake were measured from weaning until adulthood (100 days old). Glucose and insulin tolerance, and intracerebroventricular insulin (10⁻³ mmol/L) tests were performed to assess peripheral and central insulin-glucose homeostasis in adult rats. Blood, hypothalamus, visceral fat pad and lean mass were collected. Milk from SL mothers displays high content of glucose, cholesterol, triglycerides and energy (P < 0.05). Milk consumption by SL rat-offspring, in early stage of suckling, was higher than NL rats (P<0.05). At adulthood, SL-SD rats were obese, hyperphagic, dyslipidemic, hyperglycemic, glucose intolerant and IR (P < 0.05). At adulthood, SL-SD rats displayed central IR and higher hypothalamic pro-inflammatory (TNF-α, 43.5 %; IL-6, 78.5 % and IL-1β, 50.1 %, P < 0.05) cytokine. The habitual ingestion of white beans-dietary supplementation prevented all those metabolic disruptions. In summary, white beans-dietary supplementation prevented obesity and glucose-insulin homeostasis deregulation in early overfeeding rats, avoiding hypothalamic inflammatory cytokines high levels and improving insulin sensitivity.