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United States Department of Agriculture

Agricultural Research Service

Research Project: DIET AND BIOMARKERS OF CARDIOVASCULAR HEALTH Title: Postprandial lipid responses to standard carbohydrate challenges used to determine glycemic index values

Authors
item Vega-Lopez, Sonia -
item Ausman, Lynne -
item Matthan, Nirupa -
item Lichtenstein, Alice -

Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 25, 2013
Publication Date: May 8, 2013
Citation: Vega-Lopez, S., Ausman, L., Matthan, N., Lichtenstein, A. 2013. Postprandial lipid responses to standard carbohydrate challenges used to determine glycemic index values. British Journal of Nutrition. DOI:10.1017/S000711451300130X.

Interpretive Summary: The glycemic index rating system has been developed to describe the relative effect of different foods in terms of cumulative blood sugar concentrations within a few hours of food intake. The value of the system in terms of nutrition guidance is controversial. Not considered when comparing the relative effect of different foods on cumulative blood sugar concentrations are concurrent changes of post-meal cardiometabolic risk indicators. This study assessed the post-meal lipid responses to two forms of carbohydrates used as reference foods for glycemic index determinations, white bread (50 g available carbohydrate) and glucose (sugar) (50 g) under controlled conditions. Twenty adults (ages between 20-70 years) were studied twice in random order on separate days under standard conditions with each pair of reference foods (4 observations/person). Serum lipids (total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and non-esterified fatty acids [NEFA]), glucose, and insulin were monitored for 5 hours post-consumption. Oral glucose resulted in significantly greater glycemic and insulinemic responses than white bread for the first 90 minutes and greater subsequent decline after 120 minutes. The initial decline in serum NEFA was significantly greater for glucose than white bread, as was the rebound after 150 minutes. Nevertheless, type of carbohydrate had no significant effect on postprandial total, LDL- and HDL-cholesterol concentrations. Following an initial modest rise in triglyceride concentrations in response to both challenges, values dropped below fasting values for glucose but not white bread. These data suggest that the type of carbohydrate used to determine glycemic index, bread or glucose, has little or small effects on post-meal cholesterol concentrations in the blood. Differences in triglyceride and NEFA concentrations over the 5-h time period were modest and the clinical relevance is unclear.

Technical Abstract: Prior studies assessing metabolic effects of different types of carbohydrate have focused on their glycemic response. Not considered has been the response of postprandial cardiometabolic risk indicators. This study assessed the postprandial lipid responses to two forms of carbohydrates used as reference foods for glycemic index determinations, white bread (50 g available carbohydrate) and glucose (50 g) under controlled conditions and with intra-individual replicate determinations. Twenty adults (20-70 years) underwent two cycles of challenges with each pair of reference foods (4 challenges/person), administered in random order on separate days under standard conditions. Serum lipids (total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides and non-esterified fatty acids [NEFA]), glucose, and insulin were monitored for 5 h post-ingestion. Oral glucose resulted in greater glycemic and insulinemic responses than white bread for the first 90 min and greater subsequent decline after 120 min (p=0.0001). The initial decline in serum NEFA was greater after glucose than white bread, as was the rebound after 150 min (p=0.001). Nevertheless, type of carbohydrate had no significant effect on postprandial total, LDL- and HDL-cholesterol concentrations. Following an initial modest rise in triglyceride concentrations in response to both challenges, values dropped below fasting values for glucose but not bread. These data suggest that the type of carbohydrate used to determine glycemic index, bread or glucose, has little or modest effects on postprandial plasma cholesterol concentrations. Differences in triglyceride and NEFA concentrations over the 5-h time period were modest and the clinical relevance is unclear.

Last Modified: 11/28/2014
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