Effect of Four Different Meal Types on Postprandial Oxidative Stress: A Randomized Crossover Study with Healthy Subjects

Diet is one factor influencing postprandial oxidative stress (POS). Previous trials mainly used 'artificial meals' to examine the effect of diet on POS, which could give results that are not representative of the real life postprandial situation. This study evaluated the acute effect of four distinct 'real-life' meal types on POS. Thirty three heathy non-obese adults were randomized to receive one of the tested meals capturing distinct features of meals of Cantonese, Northern Chinese, South Indian and American in a series of four one-day studies. Fasting, two, four and six hours postprandial responses of biomarkers of oxidative stress, plasma glucose, lipids and high-sensitivity C-reactive protein (hsCRP) were measured. Mean plasma allantoin concentration significantly increased for all meals at two-hours after ingestion, levels peaked at four-hours and declined by 6-hours post-ingestion, though baseline levels regained only with the Cantonese meal. The magnitude of postprandial increase in plasma allantoin concentration was smallest with the Cantonese meal and greatest with the American meal. These was less marked differences in postprandial changes in urine F2-isoprostanes (F2-IsoPs) across meals, but urine F2-isoPs concentrations significantly increased for each meal during the six-hour postprandial period. There were differential meal effects on the postprandial changes in plasma glucose and triglyceride concentrations. Postprandial triglyceride levels significantly increased for all meals except for the Cantonese meal. Plasma hsCRP did not change with time or meal type. Our study demonstrates significant differential acute effects of four distinct meal types on POS in healthy adults.