title: Dietary glycemic index and glycemic load, carbohydrate and fiber intake, and measures of insulin sensitivity, secretion, and adiposity in the Insulin Resistance Atherosclerosis Study.
abstract: OBJECTIVE
  We studied the association of digestible carbohydrates, fiber intake, glycemic index, and glycemic load with insulin sensitivity (S(I)), fasting insulin, acute insulin response (AIR), disposition index, BMI, and waist circumference.
  
  
  METHODS
  Data on 979 adults with normal (67%) and impaired (33%) glucose tolerance from the Insulin Resistance Atherosclerosis Study (1992-1994) were analyzed. Usual dietary intake was assessed via a 114-item interviewer-administered food frequency questionnaire from which nutrient intakes were estimated. Published glycemic index values were assigned to food items and average dietary glycemic index and glycemic load calculated per subject. S(I) and AIR were determined by frequently sampled intravenous glucose tolerance test. Disposition index was calculated by multiplying S(I) with AIR. Multiple linear regression modeling was employed.
  
  
  RESULTS
  No association was observed between glycemic index and S(I), fasting insulin, AIR, disposition index, BMI, or waist circumference after adjustment for demographic characteristics or family history of diabetes, energy expenditure, and smoking. Associations observed for digestible carbohydrates and glycemic load, respectively, with S(I), insulin secretion, and adiposity (adjusted for demographics and main confounders) were entirely explained by energy intake. In contrast, fiber was associated positively with S(I) and disposition index and inversely with fasting insulin, BMI, and waist circumference but not with AIR.
  
  
  CONCLUSIONS
  Carbohydrates as reflected in glycemic index and glycemic load may not be related to measures of insulin sensitivity, insulin secretion, and adiposity. Fiber intake may not only have beneficial effects on insulin sensitivity and adiposity, but also on pancreatic functionality.
authors.affiliation: Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, 800 Sumter Street, Columbia, SC 29205, USA. liese@sc.edu
authors.forename: Angela D
authors.initials: AD
authors.lastname: Liese
authors.forename: Mandy
authors.initials: M
authors.lastname: Schulz
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
authors.forename: Thomas M S
authors.initials: TM
authors.lastname: Wolever
authors.forename: Ralph B
authors.initials: RB
authors.lastname: D'Agostino
authors.forename: Karen C
authors.initials: KC
authors.lastname: Sparks
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Mayer-Davis
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D050197:Atherosclerosis / Q000178:diet therapy*; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D004040:Dietary Carbohydrates; D004043:Dietary Fiber; D005215:Fasting; D005260:Female; D018149:Glucose Intolerance / Q000178:diet therapy; D038321:Glycemic Index; D006801:Humans; D007328:Insulin / Q000097:blood* / Q000378:metabolism; D007333:Insulin Resistance; D000078790:Insulin Secretion; D008297:Male; D009747:Nutritional Physiological Phenomena; D012016:Reference Values; D012907:Smoking
chemical_list: D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004043:Dietary Fiber; D007328:Insulin