Effect of a Sugar Replacement on Blood Glucose Levels in Healthy Adults

Effect of the Replacement of Glycaemic Carbohydrates With Galacto-Oligosaccharide (GOS) Supplementation on Postprandial Glycaemic Response in Healthy Adults

Diabetes and cardiovascular disease account for millions of deaths per year. One of the risk factors for both conditions is high blood sugar, particularly after eating (postprandial hyperglycaemia). Lowering blood sugar levels after a meal is expected to have a positive effect on preventing metabolic and cardiovascular diseases and improving the metabolic control of those who already suffer from these conditions.

The aim of this study is to investigate the effect of Oligomate® (beta-galacto-oligosaccharide) on postprandial glycaemia when used as a partial replacement of glycaemic carbohydrates in a beverage in otherwise healthy volunteers. Volunteers will be given water with either Oligomate® or glucose (control) added. Blood samples will be collected at eight time points (two before drinking the beverage and six after) to measure glucose and insulin levels.

A single-centre, single-blind, randomised, controlled, cross-over, acute feeding trial will be conducted. The recruitment and study visits will be carried out at the Human Intervention Studies Unit (HISU) of the Rowett Institute.

A recruitment visit will be scheduled to screen for eligibility. During the visit, informed consent will be obtained before volunteers complete a health questionnaire, have their height and weight measured, and their veins checked to assess suitability for blood sample collection. A finger prick blood sample will then be taken to measure HbA1c levels. If a volunteer is eligible, the first study visit will be scheduled and they will be asked to fast for 12 hours the night before. A frozen high carbohydrate vegetarian ready-meal will be provided, which they will consume at home the evening before the study visit and before the fasting period.

During the study visits, the postprandial glycaemic response will be measured immediately after consumption of the supplement or control on two occasions separated by a wash-out period of 7-14 days. Briefly, subjects will arrive in the morning after having consumed the high carbohydrate meal the night before, followed by a 12 hr overnight fast. After recording body weight, a cannula will be inserted into an antecubital vein of one arm by a trained cannulist to allow repeated blood sampling during the assessment (approx. 6 ml collected per sample time to a total of 48 ml per visit). After obtaining two initial fasting blood samples (at -10min and -5min), subjects will consume the test beverage within 5 min. Further blood samples will be obtained at 15, 30, 45, 60, 90 and 120 min after ingestion to complete the postprandial glycaemic response assessment.

At the end of the first visit volunteers will receive the second ready-meal, identical to the first, which they will be asked to consume the evening before the second study visit, before the fasting period commences. During the second study visit, participants will consume the same beverage with the alternate supplement and complete the opposite arm of the postprandial glycaemic response assessment.

Inclusion Criteria:

• Healthy Men or Women
• Body Mass Index (BMI) 18.5-29.9 kg/m^2
• Between 18 and 65 years of age
• Compliant (i.e., understands and is willing, able, and likely to comply with the experimental procedure and safety guidelines)
• Able to provide informed consent
• Premenopausal women must have a regular cycle or be on hormonal contraception.

Exclusion Criteria:

• Diabetes mellitus (all types including gestational diabetes)
• HbA1c result over the study limit [healthy range of between 4% and 5.9%]
• Endocrine disease (e.g., Cushing's syndrome)
• Any food allergy or intolerance, or following Vegan diet
• Medications that increase blood glucose (e.g., steroids, protease inhibitors, antipsychotics, antihypertensives, statins, diuretics, nicotinic acid, etc.)
• Medications that lower glycemia (e.g., anti-hyperglycaemics, insulin, beta- blockers, etc.)
• Medication affecting glucose regulation, appetite, and/or digestion/absorption of nutrients, antibiotics
• Major medical or surgical event requiring hospitalization in the previous 3 months
• Pregnant or lactating
• Participation in another clinical/supplementation trial or actively trying to reduce body weight
• Unable to comply with experimental procedures and safety guidelines
• Unable to give consent
• Smokers
• Travel during the study period