Acute Effect of Diets Varying in Glycemic Index and Glycemic Load on Blood Glucose, Insulin and Measures of Oxidative Stress

Background Epidemiological studies indicate that low glycemic index (GI) and glycemic load (GL) diets may decrease risk for the development of coronary heart disease (CHD) and diabetes. Clinical evidence indicates that elevations in postprandial glycemia is associated with increased oxidative stress. As such, dietary strategies which limit postprandial glycemia may be of benefit in moderating oxidative damage. We assessed the effect of foods varying in GI and GL on postprandial glycemia, insulinemia and measures of oxidative damage. Methods Fifteen healthy subjects were fed 5 test meals: 50g available carbohydrate from white bread (control), which was tested twice; 50g available carbohydrate from pasta; 100g available carbohydrate from pasta; and 100g available carbohydrate from white bread. Blood samples were obtained over the following 4 hours. Results Compared to the white bread control (50 g available carbohydrate), the area under the 2‐hour glycemic response curve was significantly greater for 100g available carbohydrate from white bread (mean±SE) 141±15 (P<0.05); was significantly reduced for 50g available carbohydrates from pasta (71±6; P<0.05); and was unchanged for 100g available carbohydrates from pasta (90±10; P<0.05). Conclusion Altering the glycemic index and glycemic load of the diet can greatly affect the postprandial glycemic response curve, which may have implications for oxidative damage and risk of CHD and diabetes.