Postprandial oxidative stress in response to dextrose and lipid meals of differing size

We have recently noted that ingestion of dietary lipid (in the form of heavy whipping cream) leads to greater oxidative stress than dietary carbohydrate (in the form of dextrose), when consumed in isocaloric amounts. Objective: In the present investigation we attempted to replicate our work and also to determine the oxidative stress response to dextrose and lipid meals of two different kilocalorie (kcal) amounts. Design: Nine young (22 +/- 2 years), healthy men consumed in a random order, cross-over design one of four meals/drinks: dextrose at 75 g (300 kcals), dextrose at 150 g (600 kcals), lipid at 33 g (300 kcals), lipid at 66 g (600 kcals). Blood samples were collected Pre meal, and at 30 min, 60 min, 120 min, and 180 min post meal. Samples were assayed for glucose, triglycerides (TAG), malondialdehyde (MDA), and hydrogen peroxide (H2O2). Area under the curve (AUC) was calculated for each variable, and a 4 x 5 ANOVA was utilized to further analyze data. Results: A meal x time effect (p = 0.0002) and a time effect was noted for glucose (p < 0.0001; 30 min > Pre, 1 hr, 2 hr, and 3 hr). The dextrose meals primarily contributed to this time effect. No other effects were noted for glucose (p > 0.05). A meal effect was noted for TAG (p = 0.01; 66 g lipid meal > 75 g and 150 g dextrose meals). No other effects were noted for TAG (p > 0.05). An AUC effect was noted for MDA (p = 0.04; 66 g lipid meal > 75 g and 150 g dextrose meals). A meal x time effect (p = 0.02) and a meal effect was noted for MDA (p = 0.004; 66 g lipid meal > 75 g and 150 g dextrose meals). No time effect was noted for MDA (p = 0.72). An AUC effect was noted for H2O2 (p = 0.0001; 66 g lipid meal > 33 g lipid meal and 75 g and 150 g dextrose meals). A meal x time effect (p = 0.0002), a meal effect (p < 0.0001; 66 g lipid meal > 33 g lipid meal and 75 g and 150 g dextrose meals), and a time effect was noted for H2O2 (p < 0.0001; 2 hr > Pre, 30 min, and 1 hr; 3 hr > Pre). The time effect for H2O2 was primarily influenced by the 66 g lipid meal. Conclusions: These data indicate that 1) minimal oxidative stress is observed following ingestion of dextrose loads of either 75 g or 150 g, or a lipid load of 33 g and 2) lipid ingestion at 66 g leads to greater oxidative stress than lipid at 33 g or dextrose at either 75 g or 150 g. Hence, in a sample of young and healthy men, only 66 g of lipid (taken in the form of heavy whipping cream) leads to a significant increase in blood oxidative stress, as measured by MDA and H2O2.