Phaseolus vulgaris extract affects glycometabolic and appetite control in healthy human subjects

Extracts of Phaseolus vulgaris (beans) are known to reduce glycaemia and food intake in rodents and humans. The present study evaluated the effects of a new, standardised and purified P. vulgaris extract (PVE), when employed as a supplement in a mixed balanced meal (60 % carbohydrates, 25 % lipids and 15 % protein), on glycometabolic and appetite control. To this end, a randomised, double-blind, placebo-controlled study was performed in twelve volunteers. Plasma glucose, insulin, C-peptide, ghrelin and satiety sensation ratings were assessed at baseline and during 3 h after meal consumption associated with PVE (100 mg) or placebo. Compared with placebo, PVE consumption resulted in lower increments in glucose (+15·4 (sem 5·4) v. 26·1 (SEM 7·3) %, P= 0·04 at 30 min), insulin (+981 (SEM 115) v. 1325 (SEM 240) %, P= 0·04 between 45 and 120 min) and C-peptide (+350 (SEM 27) v. 439 (SEM 30) %, P= 0·04 between 30 and 90 min). In the first 2 h, plasma ghrelin decreased similarly in both groups but did not rebound as in placebo thereafter (P= 0·04). Correspondingly, satiety sensation in the third hour was significantly reduced in the placebo but not in the PVE condition. PVE induced a lower desire to eat than placebo (P= 0·02) over the 3 h. In conclusion, PVE supplementation reduced postprandial glucose, insulin and C-peptide excursions, suppressed ghrelin secretion and affected satiety sensations, inducing a lower desire to eat. These results support that further studies are needed to prove the concept of employing PVE as a supplement in mixed balanced meals in obese, glucose-intolerant and diabetic subjects.