Effect of Lactose on Blood Lipids

Revealing the Mechanisms by Which Milk Sugars Exaggerate Postprandial Lipaemia

This study aims to determine to what extent ingestion of free sugars influence postprandial triglyceridaemia in men and women.

Each participant will undergo three experimental trials in a randomized, crossover research design. On each study day, participants will consume a test drink containing standardised amounts of carbohydrate and fat followed by collection of blood and breath samples to assess metabolic responses during the 6 hour postprandial period. Trials will be identical except for the type of carbohydrate contained within the test drink: 1) maltodextrin (glucose polymer), 2) lactose (galactose-glucose disaccharide) and 3) sucrose (fructose-glucose disaccharide).

Inclusion Criteria:

• Age: 18-50 years and premenopausal (for women)

Exclusion criteria:

• Weight instability (>5 kg change in body mass within last 6 months)
• Diagnosis of any form of diabetes
• Intolerances or allergies to any of the study procedures (e.g. lactose intolerance)
• Galactose disorders (e.g. galactokinase deficiency, UDPgalactose-4-epimerase deficiency, galactose-1-phosphate uridyl transferase deficiency)
• Fructose malabsorption
• Inborn errors of fructose metabolism (e.g. fructokinase deficiency, aldolase B deficiency, fructose-1,6-bisphosphatase deficiency)
• Pregnant or lactating
• Any condition that could introduce bias to the study (e.g. diagnoses of lipid disorders, including cardiovascular disease, or therapies that alter lipid or glucose metabolism, such as statins or niacin).