Extended prandial glycemic profiles of foods as assessed using continuous glucose monitoring enhance the power of the 120-minute glycemic index.
BACKGROUND
The glycemic index (GI) is routinely measured 120 minutes after food intake (GI120). The purpose of this prospective open label study was to assess (1) the dynamics of glycemia over the 210 minutes following food consumption and (2) the evolution of GIs based on 120-, 150-, 180-, and 210-minute glycemic profiles.


METHODS
Twenty healthy subjects (mean +/- SE; 21.9 +/- 1.39 years of age; body mass index 23.6 +/- 0.63 kg/m(2); 7 men and 13 women) completed the study. Each subject consumed 10 different foods with known GI120 on three separate occasions at four different times of day according to a defined meal plan over a 9-day period; 32 meals were evaluated. The GIs for intervals of 120, 150, 180 and 210 minutes after food consumption were determined using a continuous glucose monitoring system (CGMS) to measure glycemia. The Wilcoxon signed-rank test was applied to compare the GIs.


RESULTS
Glycemia returned to baseline within 120 minutes for honey and tomato soup; within 210 minutes for white bread, choco-rice cookies, fish and potatoes, wafers, and meat ravioli with cheese; and later for dark chocolate, apricot dumplings, and choco-wheat cookies. The extended GIs were higher than the respective GI120s in eight of the foods.


CONCLUSIONS
The 120-minute glycemic index fails to fully account for changes in glycemia after ingestion of a mixed meal because glycemia remains above baseline for a longer period. The CGMS is a convenient method to determine the glucose response/GIs over intervals extended up to 210 minutes, which is adequate time for the absorption of most foods.
Department of Physiology, Faculty of Medicine, Palacký University Olomouc, Olomouc, Czech Republic. rudolf.chlup@fnol.cz
Rudolf
R
Chlup
Karolina
K
Peterson
Jana
J
Zapletalová
Pavla
P
Kudlová
Pavel
P
Seckar
D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D004435:Eating / Q000502:physiology*; D005260:Female; D005502:Food; D038321:Glycemic Index / Q000502:physiology*; D006801:Humans; D008297:Male; D012984:Software; D013995:Time
D001786:Blood Glucose