Habitual nutrient intakes and postprandial glycaemic responses to glucose and orange juice among ethnically diverse adults in London: an exploratory cross-sectional analysis

Background Postprandial glycaemic response (PPGR) is an important determinant of cardiometabolic risk; however, the association of habitual dietary nutrient intakes with PPGR across ethnically diverse populations remains poorly understood. Objectives To compare differences in nutrient intakes among White Caucasian, Black African-Caribbean, and South Asian (SA) adults living in London, and to examine associations between habitual nutrient intakes and PPGRs to a standardized glucose drink and orange juice (OJ). Methods Eighty-six healthy adults (White: n = 35, Black: n = 17, SA: n = 34) completed a 4-day estimated food diary and two postprandial glycaemic challenges following an overnight fast. Capillary blood glucose was measured at baseline (fasting) and every 30 min for 2 h. PPGR outcomes included total area under the curve (AUC) (0–120 min) and observed peak values (PVs) for each drink. Results White participants reported significantly higher intakes of total energy, dietary fiber, calcium, magnesium, zinc, vitamin A, thiamine (B1), vitamin E, and folate than Black and/or SA participants. After adjusting for total energy intake, only dietary fiber, magnesium and folate intakes remained significantly different. SA participants exhibited significantly higher AUCs and PVs following consumption of both beverages than White participants or Black participants. In unadjusted regression analyses, nutrient intakes of dietary fiber, percentage energy from fat (fat %), and several micronutrients were associated with at least one PPGR outcome. After adjustment for age, body fat percentage, ethnicity, and total energy intake, dietary fiber, magnesium, thiamine (B1), and folate intakes were inversely associated with OJ-PV, whereas fat intake as a percentage of total energy was positively associated with OJ-AUC. Conclusion These findings indicate that habitual dietary nutrient intakes were associated with PPGRs. Whether these dietary differences contribute to ethnic variation in PPGR requires further investigation.