Acute and Long-term Health Effects of Various Carbohydrates on Blood Glucose Management in Humans

Dietary fibre, especially soluble fibre, has several health benefits such as lowering the risks for cardiovascular disease, stroke, diabetes, obesity, and gastrointestinal diseases. Resistant dextrin is a non-viscous soluble fibre, can be introduced quite easily in foods or as drinks, and it is well tolerated. This study aims to investigate if daily supplementation of habitual diets with resistant dextrin over 8 weeks affect glycaemic control via insulin sensitivity, intestinal fermentation, energy expenditure and fat oxidation in adults with increased risk for type 2 diabetes. The primary outcome is the effect on glycaemic control (fasting glucose, insulin, insulin sensitivity and 24 hour glycaemic response from CGMS). The secondary outcomes are the effects on fasting lipids, energy expenditure and fuel utilization in a whole room calorimeter and appetite regulation.

Dietary fibre has several health benefits such as lowering the risks for cardiovascular disease, stroke, diabetes, obesity, and gastrointestinal diseases. Dietary fibre intake has regularly been reported to be below the daily recommended levels. Based on the 2010 National Nutrition Survey, 21% of Singaporeans did not meet the recommended daily intake of dietary fibre. While increasing fruit and vegetables intake remains the primary strategy to promote fibre intake, an alternative is to supplement a daily diet with dietary fibre, especially soluble fibre, to improve health.

Resistant dextrin is a non-viscous soluble fibre that exhibits prebiotic properties and it has been shown to alter gastrointestinal ecology. Emerging evidence suggests that resistant dextrin reduced insulin resistance in both healthy individuals and adults with type 2 diabetes, resulting in better blood glucose control. In term of its cardio-protective effects, resistant dextrin has also been shown to lower blood cholesterol levels and reduced inflammation biomarkers. Resistant dextrin has also been shown to suppress hunger and increase satiety, leading to reduced daily energy intake and greater body weight loss.

To date, evidence from clinical trials, notably among Asians is still insufficient to make dietary recommendations. In addition, the possibility of short-chain fatty acid production in stimulating diet-induced thermogenesis and fat oxidation has not been explored. These are the novel aspects that our proposed study aims to investigate.

Eligibility Criteria:
Inclusion Criteria:

* 21 to 60 years old
* Group A: 21 - 25 kg/m2, with first degree family history of type 2 diabetes, or Group B: 23 - 30 kg/m2, with waist circumference \>85 cm for males and \>82 cm for females

Exclusion Criteria:

* • Consume fibre supplements or any other supplements that is likely to interfere with study outcomes

  * Have any major organ dysfunction (e.g. cardiovascular, respiratory, hepatic, renal, gastrointestinal) that may influence taste, olfaction, appetite, digestion, metabolism, absorption or elimination of test foods, nutraceutical or drug
  * Smoking
  * Have any metabolic diseases (e.g. diabetes, hypertension)
  * Have medical conditions and/or taking medications known to affect glycaemia (e.g. glucocorticoids, thyroid hormones, thiazide diuretics)
  * Have glucose-6-phosphate dehydrogenase (G6PD) deficiency
  * Have any severe food allergy (e.g. anaphylaxis to peanuts), or any other known food allergy/intolerance
  * Have active Tuberculosis (TB) or currently receiving treatment for TB
  * Have any known Chronic infection or known to suffer from or have previously suffered from or is a carrier of Hepatitis B Virus (HBV), Hepatitis C Virus (HCV), Human Immunodeficiency Virus (HIV)
  * A team member of the study or their immediate family members (i.e. spouse, parent, child, or sibling, whether biological or legally adopted)
  * Enrolled in a concurrent research study judged not to be scientifically or medically compatible with the study of the CNRC.
  * Intentionally restricting food intake
  * Have poor veins impeding venous access
  * Have any history of severe vasovagal syncope (blackouts or near faints) following blood draws
  * Have claustrophobia