title: Effects of a beetroot juice with high neobetanin content on the early-phase insulin response in healthy volunteers.
abstract: Produce rich in phytochemicals may alter postprandial glucose and insulin responses by interacting with the pathways that regulate glucose uptake and insulin secretion in humans. The aims of the present study were to assess the phytochemical constituents of red beetroot juice and to measure the postprandial glucose and insulin responses elicited by either 225 ml beetroot juice (BEET), a control beverage matched for macronutrient content (MCON) or a glucose beverage in healthy adults. Beetroot juice was a particularly rich source of betalain degradation compounds. The orange/yellow pigment neobetanin was measured in particularly high quantities (providing 1·3 g in the 225 ml). A total of sixteen healthy individuals were recruited, and consumed the test meals in a controlled single-blind cross-over design. Results revealed a significant lowering of the postprandial insulin response in the early phase (0-60 min) (P < 0·05) and a significantly lower glucose response in the 0-30 min phase (P < 0·05) in the BEET treatment compared with MCON. Betalains, polyphenols and dietary nitrate found in the beetroot juice may each contribute to the observed differences in the postprandial insulin concentration.
authors.affiliation: Functional Food Centre , Oxford Brookes University , Gipsy Lane, Oxford OX3 0BP , UK.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Wootton-Beard
authors.affiliation: Human Nutrition Research Centre, School of Agriculture and Rural Development , Newcastle University , Newcastle upon Tyne NE1 7RU , UK.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Brandt
authors.affiliation: Cell Systems Modelling Group , Oxford Brookes University , Gipsy Lane, Oxford OX3 0BP , UK.
authors.forename: David
authors.initials: D
authors.lastname: Fell
authors.affiliation: Functional Food Centre , Oxford Brookes University , Gipsy Lane, Oxford OX3 0BP , UK ; Human Nutrition Research Centre, School of Agriculture and Rural Development , Newcastle University , Newcastle upon Tyne NE1 7RU , UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Warner
authors.affiliation: Functional Food Centre , Oxford Brookes University , Gipsy Lane, Oxford OX3 0BP , UK ; Department of Nutrition and Dietetics , Monash University , Faculty of Medicine, Nursing and Health Sciences, 264 Ferntree Gully Road, Vic 3168 , Australia.
authors.forename: Lisa
authors.initials: L
authors.lastname: Ryan
keywords: BEET, beetroot beverage; Betalains; CHO, carbohydrate; GLUC, glucose beverage; MCON, matched control beverage; Phytochemicals; Postprandial glycaemia; iAUC, incremental AUC; sAUC, segmental AUC