Whole-grain foods do not affect insulin sensitivity or markers of lipid peroxidation and inflammation in healthy, moderately overweight subjects

J Nutr. 2007 Jun;137(6):1401-7. doi: 10.1093/jn/137.6.1401.

Abstract

High intakes of whole grain foods are inversely related to the incidence of coronary heart diseases and type 2 diabetes, but the mechanisms remain unclear. Our study aimed to evaluate the effects of a diet rich in whole grains compared with a diet containing the same amount of refined grains on insulin sensitivity and markers of lipid peroxidation and inflammation. In a randomized crossover study, 22 women and 8 men (BMI 28 +/- 2) were given either whole-grain or refined-grain products (3 bread slices, 2 crisp bread slices, 1 portion muesli, and 1 portion pasta) to include in their habitual daily diet for two 6-wk periods. Peripheral insulin sensitivity was determined by euglycemic hyperinsulinemic clamp tests. 8-Iso-prostaglandin F(2alpha) (8-iso PGF(2alpha)), an F(2)-isoprostane, was measured in the urine as a marker of lipid peroxidation, and highly sensitive C-reactive protein and IL-6 were analyzed in plasma as markers of inflammation. Peripheral insulin sensitivity [mg glucose . kg body wt(-1) . min(-1) per unit plasma insulin (mU/L) x 100] did not improve when subjects consumed whole-grain products (6.8 +/- 3.0 at baseline and 6.5 +/- 2.7 after 6 wk) or refined products (6.4 +/- 2.9 and 6.9 +/- 3.2, respectively) and there were no differences between the 2 periods. Whole-grain consumption also did not affect 8-iso-PGF(2alpha) in urine, IL-6 and C-reactive protein in plasma, blood pressure, or serum lipid concentrations. In conclusion, substitution of whole grains (mainly based on milled wheat) for refined-grain products in the habitual daily diet of healthy moderately overweight adults for 6-wk did not affect insulin sensitivity or markers of lipid peroxidation and inflammation.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Blood Pressure / drug effects
  • Body Mass Index
  • Cross-Over Studies
  • Diet
  • Dinoprost / analogs & derivatives*
  • Dinoprost / urine
  • Edible Grain*
  • Female
  • Humans
  • Inflammation / blood
  • Inflammation / urine
  • Insulin / blood*
  • Interleukin-6 / blood*
  • Lipids / blood*
  • Male
  • Middle Aged
  • Overweight

Substances

  • Insulin
  • Interleukin-6
  • Lipids
  • 8-epi-prostaglandin F2alpha
  • Dinoprost