Effects of Surgical and Dietary Weight Loss Therapy for Obesity on Gut Microbiota Composition and Nutrient Absorption

Abstract

Evidence suggests a correlation between the gut microbiota composition and weight loss caused by caloric restriction. Laparoscopic sleeve gastrectomy (LSG), a surgical intervention for obesity, is classified as predominantly restrictive procedure. In this study we investigated functional weight loss mechanisms with regard to gut microbial changes and energy harvest induced by LSG and a very low calorie diet in ten obese subjects (n = 5 per group) demonstrating identical weight loss during a follow-up period of six months. For gut microbiome analysis next generation sequencing was performed and faeces were analyzed for targeted metabolomics. The energy-reabsorbing potential of the gut microbiota decreased following LSG, indicated by the Bacteroidetes/Firmicutes ratio, but increased during diet. Changes in butyrate-producing bacterial species were responsible for the Firmicutes changes in both groups. No alteration of faecal butyrate was observed, but the microbial capacity for butyrate fermentation decreased following LSG and increased following dietetic intervention. LSG resulted in enhanced faecal excretion of nonesterified fatty acids and bile acids. LSG, but not dietetic restriction, improved the obesity-associated gut microbiota composition towards a lean microbiome phenotype. Moreover, LSG increased malabsorption due to loss in energy-rich faecal substrates and impairment of bile acid circulation. This trial is registered with ClinicalTrials.gov NCT01344525.

Obesity diabetes and the role of bile acids in metabolism

“…A recent review of bariatric surgery in adolescent patients found little difference in weight reduction when Roux en Y was compared with sleeve gastrectomy [25] . The patients who had the Roux en Y procedure were the heaviest at the start with a mean BMI of 54 (52)(53)(54)(55), whereas the sleeve gastrectomy subjects had a mean BMI of 50 (48)(49)(50)(51)(52). The percent change was 28 for the Roux en Y as compared to 26 for the sleeve gastrectomy operation.…”

“…The effects of surgical and dietary weight loss for obesity on gut microbiota composition and nutrient absorption have been reported recently [51] . Fecal sampling showed that the low calorie diet resulted in less changes than slieve gastrectomy, which changed the ratio of firmicutes/ bacteroidetes.…”

Gut Microbiota: Influence of Aloe vera gel and Calorie Restriction

“…This trial is registered with clinical Trial.gov NCT01344525. Official title: Pilot project on interdisciplinary therapy of obesity [15] . Obesity has been linked to not only to the composition of human microbiota, but also to the production of SCFAs.…”

The role of gut microbiota in metabolic regulation

“…Совсем недавно было опубликовано исследование на здоровых добровольцах, где доказано, что изменения в микро-флоре на фоне «белковой» диеты происходят очень быстро (в течение одного дня), а диета с повышенным количеством волокон, напротив, не оказывает значи-мого эффекта [38]. В другом же исследовании на паци-ентах с ожирением отмечалось повышение соотношения Firmicutes/Bacteroidetes на фоне низкокалорийной диеты с добавлением растворимых пищевых волокон, являю-щихся субстратом для выработки КЦЖК [39]. Вероятно, имеет смысл изучение различных вариантов диет в отно-шении их влияния на микрофлору кишечника.…”

“…Клиническое исследование по изменению со-става микрофлоры после лапароскопической продоль-ной резекции желудка показало снижение соотношения Firmicutes/Bacteroidetes, снижение распространенности бутират-продуцирующих бактерий по сравнению с низ-кокалорийной диетой с повышенным содержанием пи-щевых волокон [44]. Наиболее логичным объяснением такого явления представляется снижение калорийности рациона и снижение потребления пищевых волокон в пользу увеличения количества белка в рационе пита-ния.…”