Co-ingestion of antioxidant drinks with an unhealthy challenge meal fails to prevent post-prandial endothelial dysfunction: an open-label, crossover study in healthy older adults

Endothelial function is impaired for several hours after an unhealthy challenge meal (e.g high calorie, high fat)(1). This impairment hasbeen shown to be abolished in the presence of antioxidants(2), suggesting that reactive oxygen species (ROS) may play an importantrole in the induced dysfunction. In this study, we assessed whether drinks with high-antioxidant capacity impacted endothelial dys-function induced by an unhealthy challenge meal.The study was an open-label randomised crossover design: 7 healthy older adults (1 male, 6 females; BMI 25-35; mean age 57 years)were recruited to the study and completed four experimental trials. Participants received either water, orange juice, green tea or redwine with a high calorie meal (>900 kcal; >50g fat) following an overnight fast. Endothelial function (primary measure) was assessedbyflow-mediated dilatation (FMD) of the brachial artery immediately before (baseline) and two hours after the meal; blood sampleswere also taken at these time points for routine lipid and glucose analysis, as well as measurement of oxidised low density lipoprotein(ox-LDL) and oxygen radical antioxidant capacity (ORAC). Participants returned at weekly intervals to complete the remaining armsof the study. Data was analysed using a 2-factor repeated measures ANOVA.The results demonstrate that two hours following an unhealthy meal challenge there was a substantial increase in circulating tri-glycerides (≥100 %, P < 0.001), but not total cholesterol or glucose (both P > 0.05). FMD was reduced by∼30 % at this timepoint,but the effect was not attenuated by co-ingestion of any of the antioxidant drinks (Fig. 1). In addition, there was no effect of themeal or condition on circulating levels of ox-LDL or ORAC (P > 0.05)