Abstract 17705: Differences in Body Composition Alters Glycemic Response to a Single Food in Healthy Subjects
A better understanding of potential sources of variability in glycemic index (GI) value determinations among individuals is required to define the utility of GI values for chronic disease risk assessment and management. The objective of the present study was to evaluate whether differences in body composition affected glucose homeostasis and calculated GI values in response to a single food challenge. We measured the intra-individual reproducibility (within the same individual, when repeatedly measured) and inter-individual variability (among individuals) of GI value determinations for white bread and glucose, in 63 healthy men and women aged 18 to 85 years with a wide range in body mass index (BMI, 18.5 - 35 kg/m2). Each participant underwent 3 sets of food challenges in random order (6 sessions), after abstaining from strenuous physical activity and alcohol intake for at least 72 hours prior to each session. Each set involved ingestion of glucose (500mL glucose solution, [100g/L]) and white bread (96 gm Pepperidge Farm Original White Bread; 50 gm carbohydrate) + 500mL water. Changes in blood glucose were monitored (arterialized venous blood sampling at 0, 15, 30, 45, 60, 90, and 120 mins) and GI values were calculated using the incremental AUC method. Body composition was measured by dual-energy X-ray absorptiometry and percent total fat (TF), lean muscle mass (LM) and lean plus bone mineral content (LM+BMC) was calculated for whole body, trunk and abdominal regions. The mean (± SD) GI value for white bread was 62 ± 15. The average intra-individual coefficient of variation (CV) was 42% and the inter-individual CV was 25%. No significant association was observed between the GI value for white bread and sex or BMI. After adjustment for age, GI value was positively associated with whole body TF (p =0.060), and trunk TF (p=0.055) and negatively associated with whole body LM (p=0.054), trunk LM (p=0.055), whole body LM+BMC (p=0.074) and trunk LM+BMC (p=0.056). No significant association was observed with abdominal TF, LM or LM+BMC. These data indicate that the variability in GI values is explained, in part, by differences in body composition and this should be factored into interpretation of dietary GI values and chronic disease risk.
- © 2013 by American Heart Association, Inc.