Investigating the role of short -chain fatty acids in glycaemic regulation in humans
File(s)
Author(s)
Alshehhi, Sumayya
Type
Thesis
Abstract
ABSTRACT
Introduction
Obesity increases individual risk for cardiometabolic diseases, including type 2 diabetes. Dietary fibre has emerged as an important modifiable risk factor for obesity, partially due
to its fermentation by the gut microbiota to produce SCFAs-primarily acetate, propionate and butyrate. Despite increasing interest in their metabolic effects, human evidence on
the impact of SCFAs on glycaemic regulation remains limited and inconsistent. This thesis therefore aimed to evaluate the most recent evidence linking SCFAs with glycaemic
control measures in humans.
Method
Three complementary studies were conducted. First, a systematic review and meta analysis synthesized evidence published up to December 2021 on the effects of SCFAs
on glycaemic outcomes. Second, a secondary analysis of data from the Low Caloric Diet Diabetes Mellitus (LCDDM) study examined associations between circulating acetate and
glycaemic measures in obese type 2 diabetes undergoing a low-calorie dietary intervention. Third, a 12-month randomised double -blind parallel controlled study
assessed the effects of inulin propionate ester (IPE) supplementation on weight and glucose regulations in young overweight adults.
Result
The systematic review included 46 studies (n=913). Vinegar intake significantly reduced acute postprandial glucose responses in individuals with impaired glucose tolerance, type
2 diabetes, and healthy participants. However, neither acute nor chronic administration of acetate, propionate or butyrate affected glycaemic measures. In the LCDDM analysis,
no significant associations were found between plasma acetate and glycaemic measures, but a negative association with body weight and body mass index was observed in
specific subgroups. The IPE trial showed no significant effect on weight gain prevention and a small increase in blood glucose, despite good compliance.
Conclusion
Overall, SCFAs had no effect on the glycaemic measures. This thesis provides evidence from specific populations and highlights the need for further investigation to clarify the
underlying mechanisms and the reasons for the divergence in findings.
Introduction
Obesity increases individual risk for cardiometabolic diseases, including type 2 diabetes. Dietary fibre has emerged as an important modifiable risk factor for obesity, partially due
to its fermentation by the gut microbiota to produce SCFAs-primarily acetate, propionate and butyrate. Despite increasing interest in their metabolic effects, human evidence on
the impact of SCFAs on glycaemic regulation remains limited and inconsistent. This thesis therefore aimed to evaluate the most recent evidence linking SCFAs with glycaemic
control measures in humans.
Method
Three complementary studies were conducted. First, a systematic review and meta analysis synthesized evidence published up to December 2021 on the effects of SCFAs
on glycaemic outcomes. Second, a secondary analysis of data from the Low Caloric Diet Diabetes Mellitus (LCDDM) study examined associations between circulating acetate and
glycaemic measures in obese type 2 diabetes undergoing a low-calorie dietary intervention. Third, a 12-month randomised double -blind parallel controlled study
assessed the effects of inulin propionate ester (IPE) supplementation on weight and glucose regulations in young overweight adults.
Result
The systematic review included 46 studies (n=913). Vinegar intake significantly reduced acute postprandial glucose responses in individuals with impaired glucose tolerance, type
2 diabetes, and healthy participants. However, neither acute nor chronic administration of acetate, propionate or butyrate affected glycaemic measures. In the LCDDM analysis,
no significant associations were found between plasma acetate and glycaemic measures, but a negative association with body weight and body mass index was observed in
specific subgroups. The IPE trial showed no significant effect on weight gain prevention and a small increase in blood glucose, despite good compliance.
Conclusion
Overall, SCFAs had no effect on the glycaemic measures. This thesis provides evidence from specific populations and highlights the need for further investigation to clarify the
underlying mechanisms and the reasons for the divergence in findings.
Date Issued
2024-09-06
Date Awarded
2026-02-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Frost, Gary
Publisher Department
Department of Metabolism, Digestion and Reproduction
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)