Inflammatory and oxidative stress responses to high-carbohydrate and high-fat meals in healthy humans

Abstract

The postprandial state is hypothesised to be proinflammatory and prooxidative, but the relative contributions of fat versus carbohydrate are unclear. Therefore, we examined inflammation and oxidative stress responses in serum and skeletal muscle before and after 1000 kcal meals, which were high in either fat or carbohydrate in 15 healthy individuals. Serum and muscle expression of IL6 was elevated 3 hours after each meal, independently of macronutrient composition (P < 0.01). Serum IL18 was decreased after high-fat meal only (P < 0.01). Plasma total antioxidative status and muscle Cu/Zn-superoxide dismutase were decreased after high-carbohydrate meal only (P < 0.05). We conclude that a high-carbohydrate meal may evoke a greater postprandial oxidative stress response, whereas both fat and carbohydrate increased IL6. We speculate that the observed increases in postprandial IL6, without increases in any other markers of inflammation, may indicate a normal IL6 response to enhance glucose uptake, similar to its role postexercise.

Figure 1

Levels of plasma (a) insulin, (b) glucose, (c) free fatty acid (FFA), and (d) triglycerides fasting and in response to high-carbohydrate or high-fat meals. Footnote: statistics were performed by repeated measure ANOVA.

Figure 2

Circulating and muscle gene expression of inflammatory markers in the fasting state and 3 hours after either high-carbohydrate or high-fat meals. Footnote: statistics were performed by Student's t-test, *P < 0.05.

Figure 3

Fasting and 3-hour levels of (a) plasma total antioxidant status (TAS), (b) plasma Cu-Zn superoxide dismutase, and (c) Cu-Zn superoxide dismutase expression in skeletal muscle in response to high-carbohydrate or high-fat meals. Footnote: statistics were performed by paired t-test, *P ≤ 0.05, **P ≤ 0.01.