Circulating fasting total BA was not associated with obesity .
FGF19 was inversely and faecal BA excretion was positively associated with obesity .
Roux-en-Y gastric bypass ( RYGB ) and sleeve gastrectomy ( SG )  modulated BA metabolism , ie , increased BA and FGF19 .
Our results indicate that BA metabolism is altered in obesity .
Bile acids and gut peptide secretion after bariatric surgery: a 1-year prospective randomized pilot trial.
OBJECTIVE Increased delivery of bile acid salts ( BA ) to distal L-cells and altered TGR5 receptor activation may contribute to the early and substantial increases in gut peptide secretion seen after bariatric surgery . To further eluci date a potential role of BA in the secretion of GLP-1 and PYY , we analyzed plasma BA concentrations in 14 morbidly obese patients undergoing gastric bypass or sleeve gastrectomy in a prospect i ve , r and omized 1-year trial . DESIGN AND METHODS Patients  received a st and ard test meal and blood was collected before and after eating , prior to , and 1 week , 3 months , and 12 months after surgery . RESULTS Pre-surgery , basal BA concentrations were significantly lower in bariatric patients than in healthy controls . One year post-surgery , bariatric patients expressed variably increased BA concentrations ( gastric bypass patients ∼2 fold increase , P ≤ 0.05 ) . However , whereas in both patient groups , marked increases in GLP-1 and PYY and improved glycemic control was seen already 1 week and 3 months post-surgery , changes in plasma BA followed a different pattern : basal and postpr and ial plasma BA concentrations increased much slower , more progressively with significant increases only 1-year post-surgery . CONCLUSIONS Based on these findings , BA do not appear to be key mediators of the early increase in GLP-1 and PYY response in post-bariatric patients
Circulating fasting total BA was not associated with obesity .
FGF19 was inversely and faecal BA excretion was positively associated with obesity .
Roux-en-Y gastric bypass ( RYGB ) and sleeve gastrectomy ( SG )  modulated BA metabolism , ie , increased BA and FGF19 .
Our results indicate that BA metabolism is altered in obesity .