Endocrine Abstracts

Background: Nutrition is essential in achieving maximal treatment success after bariatric surgery, and is simultaneously beneficial for avoiding long-term complications. Dietary protein could have an important role, because of its positive effects on preservation of muscle mass and induction of satiety in non-bariatric subjects. Therefore, we investigated the effects of dietary protein, assessed by amino acid composition, on satiety, hunger and gastrointestinal hormones after gastric bypass surgery.

Methods: Participants who previously had undergone primary gastric bypass surgery were studied during an oral Mixed Meal Tolerance Test (MMTT). Satiety and hunger were assessed every 30 min by means of a visual analogue scale. Blood samples were collected at baseline, every 10 min during the first half hour and every 30 min till 210 min after the start. The plasma samples were assessed for 24 amino acids including derivatives and four gastrointestinal hormones.

Results: 30 female and 12 male subjects aged 48±11 years, 31–76 months after surgery with total weight loss of 30±9% completed the MMTT. After ingestion increases in satiety, the hormones PYY, active GLP1, inactive GLP1 and most amino acids were observed, while hunger, ghrelin and citrulline declined. Satiety scores above the median were associated with increased plasma levels of PYY, active and inactive GLP1. Hunger scores below the median (indicating less hunger) were associated with increased levels of PYY and a reduced attenuation in ghrelin. Higher concentrations of several plasma levels of amino acids especially histidine, serine, arginine, glutamine and glycine were observed in subjects experiencing more satiety, higher levels of PYY, active or inactive GLP1. Additional analyses are underway.

Conclusions: Our exploratory analysis shows positive associations between various plasma amino acids in groups with differences in satiety and gastrointestinal hormones. This provides new insights to optimize the outcomes of bariatric surgery.