title: Insulin sensitivity and intake of vitamins E and C in African American, Hispanic, and non-Hispanic white men and women: the Insulin Resistance and Atherosclerosis Study (IRAS).
abstract: Elevated fasting insulin concentrations and insulin resistance have been associated with non-insulin-dependent diabetes mellitus (NIDDM), obesity, atherosclerosis, and hypertension. Vitamin E supplementation in persons with and without NIDDM may be related to greater insulin sensitivity (SI). The cross-sectional associations of the intake of vitamins E and C with SI and insulin concentrations were evaluated among African American, Hispanic, and non-Hispanic white men and women with a wide spectrum of glucose tolerance included in the Insulin Resistance and Atherosclerosis Study (IRAS) (n = 1151). Insulin sensitivity was measured by minimal model analysis of a 12-sample, insulin-modified, frequently sampled intravenous glucose tolerance test. Nutrient intake (including vitamin supplement use) was assessed with a food-frequency questionnaire modified to include foods consumed by the three ethnic groups. Linear-regression models were used, including rank of SI and the log of fasting insulin as the outcome variables. Pearson correlation coefficients for vitamins E and C in relation to rank SI were r = 0.07 (P = 0.01) and r = 0.07 (P = 0.02), respectively. After adjustment for total energy and BMI these associations were no longer statistically significant and did not differ between ethnic groups. Results were similar when vitamins E and C were combined in categories of low and high antioxidant intake. Models replicated with log of fasting insulin as the outcome variable also did not produce significant associations with vitamins E or C. Thus, these cross-sectional analyses do not support the hypothesis of improved SI with increased intake of vitamins E and C.
authors.affiliation: Department of Public Health Sciences, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC, USA.
authors.forename: L
authors.initials: L
authors.lastname: Sanchez-Lugo
authors.forename: E J
authors.initials: EJ
authors.lastname: Mayer-Davis
authors.forename: G
authors.initials: G
authors.lastname: Howard
authors.forename: J V
authors.initials: JV
authors.lastname: Selby
authors.forename: M F
authors.initials: MF
authors.lastname: Ayad
authors.forename: M
authors.initials: M
authors.lastname: Rewers
authors.forename: S
authors.initials: S
authors.lastname: Haffner
mesh_terms: D000328:Adult; D000368:Aged; D001205:Ascorbic Acid / Q000008:administration & dosage*; D044383:Black People; D001786:Blood Glucose / Q000187:drug effects; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000208:ethnology*; D004032:Diet; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D016014:Linear Models; D008297:Male; D017058:Mexican Americans; D008875:Middle Aged; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D014810:Vitamin E / Q000008:administration & dosage*; D044465:White People; D001741:Black or African American
chemical_list: D001786:Blood Glucose; D014810:Vitamin E; D001205:Ascorbic Acid