Abstract

Weight gain and risk of type 2 diabetes are inversely associated with a high intake of insoluble cereal fibres. Because nutrient-induced changes of 'satiety hormones' from the gut may play a role in this process, we evaluated the effects of purified insoluble fibres on postprandial responses of plasma peptide YY (PYY), serum ghrelin and satiety as secondary outcome measures of a study investigating effects of cereal fibres on parameters of glucose metabolism. Fourteen healthy women were studied on six occasions in a randomized, single-blind, controlled crossover design. After 24 h run-in periods and 10 h overnight fasts, subjects ingested isoenergetic and macronutrient matched portions of control white bread or fibre-enriched bread (wheat-fibre or oat-fibre) at 08.15 hours. Gut hormones and hunger scores were measured for 300 min. Basal PYY and ghrelin concentrations were not different between the test meals (P>0.15). Postprandial responses of PYY and ghrelin were blunted after the intake of wheat-fibre (total area under the curve (AUC) PYY, 177.9 (SEM 8.1) (pmol/l) min; P=0.016; ghrelin 51.0 (SEM 2.5) (pmol/l) min; P=0.003), but not after oat-fibre (PYY 226.7 (SEM 25.7) (pmol/l) min; P>0.15; ghrelin 46.2 (SEM 1.6) (pmol/l) min; P=0.127), compared to control (PYY 247.5 (SEM 25.6) (pmol/l) min; ghrelin 42.5 (SEM 1.3) (pmol/l) min). Postprandial hunger scores were unaffected by the different test meals (P>0.15). Thus, oat- and wheat-fibre consumption result in different postprandial responses of PYY and ghrelin, but interestingly do not differ in satiety effects.