title: Inhibition of the glycaemic response by onion: a comparison between lactose-tolerant and lactose-intolerant adults.
abstract: This pilot study compared inhibition of the glycaemic response to glucose by a dietary source of quercetin glucosides (onion) in lactose-tolerant adults (n=12) and lactose-intolerant adults (n=12). We hypothesised that lactose-intolerant people (who do not express lactase) will retain intact quercetin glucosides that can inhibit glucose uptake via the glucose transporter SGLT1, whereas lactose-tolerant people (who do express lactase) will hydrolyse quercetin glucosides to free quercetin that does not inhibit glucose uptake. In a glucose tolerance test, reduction in peak glucose levels by an onion meal was higher in lactose-intolerant people than in lactose-tolerant people (44.2 versus 19.3%, P=0.04). Incremental area under the blood glucose curve was reduced more in lactose-intolerant people, but was not statistically significant (54.5 versus 42.1%, P=0.42). A diet containing quercetin glucosides may be of greater benefit for glycaemic control in lactose-intolerant people than in lactose-tolerant people.
authors.affiliation: Department of Biological and Environmental Sciences, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, UK.
authors.forename: R
authors.initials: R
authors.lastname: Hoffman
authors.affiliation: Department of Biological and Environmental Sciences, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, UK.
authors.forename: G
authors.initials: G
authors.lastname: Ranjbar
authors.affiliation: Department of Biological and Environmental Sciences, School of Life and Medical Sciences, University of Hertfordshire, Hatfield, UK.
authors.forename: A M
authors.initials: AM
authors.lastname: Madden
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D004032:Diet; D004040:Dietary Carbohydrates / Q000097:blood; D005247:Feeding Behavior; D005260:Female; D000067940:Glycemic Load / Q000187:drug effects*; D006027:Glycosides / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D043322:Lactase / Q000378:metabolism; D007785:Lactose / Q000009:adverse effects / Q000378:metabolism; D007787:Lactose Intolerance / Q000097:blood*; D008297:Male; D019697:Onions / Q000737:chemistry*; D010865:Pilot Projects; D011794:Quercetin / Q000378:metabolism / Q000494:pharmacology*; D012016:Reference Values; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D006027:Glycosides; D011794:Quercetin; D043322:Lactase; D007785:Lactose