title: Dietary insulin index and insulin load in relation to biomarkers of glycemic control, plasma lipids, and inflammation markers.
abstract: BACKGROUND
  Dietary glycemic index and load are widely used to estimate the effect of carbohydrate-containing foods on postprandial blood glucose concentrations and as surrogates for insulin response. The food insulin index (II) directly quantifies the postprandial insulin secretion of a food and takes into account foods with a low or no carbohydrate content.
  
  
  OBJECTIVE
  We investigated the average dietary II and insulin load (IL) in relation to biomarkers of glycemic control, plasma lipids, and inflammation markers.
  
  
  METHODS
  In a cross-sectional setting and with the use of data from the Nurses' Health Study and the Health Professionals Follow-Up Study, we measured plasma concentrations of C-peptide, glycated hemoglobin (Hb A(1c)), HDL cholesterol, LDL cholesterol, triglycerides, C-reactive protein (CRP), and interleukin-6 (IL-6) in fasting blood samples of 4002 healthy men and women. The dietary II and IL were assessed from food-frequency questionnaires by using directly analyzed or published food II data.
  
  
  RESULTS
  After multivariate adjustment, participants in the highest quintile of II had 26% higher triglyceride concentrations than did participants in the lowest quintile of II (P for trend < 0.0001). This association was strongest in obese [body mass index (in kg/m(2)) ≥30] participants (difference between highest and lowest quintiles in the II: 72%; P for trend = 0.01). Dietary II was inversely associated with HDL cholesterol in obese participants (difference: -18%; P for trend = 0.03). Similar associations were seen for the IL. Dietary II and IL were not significantly associated with plasma C-peptide, Hb A(1c), LDL cholesterol, CRP, or IL-6.
  
  
  CONCLUSIONS
  Dietary II and IL were not associated with fasting biomarkers of glycemic control but may be physiologically relevant to plasma lipids, especially in obese individuals.
authors.affiliation: Department of Nutrition, Harvard School of Public Health, Boston, MA 02115, USA. knimptsc@hsph.harvard.edu
authors.forename: Katharina
authors.initials: K
authors.lastname: Nimptsch
authors.forename: Jennie C
authors.initials: JC
authors.lastname: Brand-Miller
authors.forename: Mary
authors.initials: M
authors.lastname: Franz
authors.forename: Laura
authors.initials: L
authors.lastname: Sampson
authors.forename: Walter C
authors.initials: WC
authors.lastname: Willett
authors.forename: Edward
authors.initials: E
authors.lastname: Giovannucci
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers; D001786:Blood Glucose / Q000032:analysis*; D015992:Body Mass Index; D002096:C-Peptide / Q000032:analysis; D002097:C-Reactive Protein / Q000032:analysis*; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007328:Insulin / Q000097:blood*; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood; D008055:Lipids / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D002096:C-Peptide; D002097:C-Reactive Protein; D006442:Glycated Hemoglobin; D007328:Insulin; D018970:Insulin-Like Growth Factor Binding Protein 1; D008055:Lipids; C032231:IGFBP1 protein, human; C517652:hemoglobin A1c protein, human