Poster Communications: Lower dietary antioxidant vitamins consumption and vascular endothelial dysfunction in older sedentary males; justification for dose adjustment?

Background, aims: Cardiovascular disease risk increases with advancing chronological age1. Moderate aerobic exercise promotes a favourable cardiovascular state and helps in maintaining vascular health subsequent to an improvement in vascular endothelial function2. However, diet plays an equally important role, if not oftentimes overlooked variable, in the prevention of cardiovascular diseases. In particular the consumption of primary water and fat-soluble chain-breaking antioxidants (vitamins C and E), given their collective capacity to constrain lipid peroxidation and attenuate oxidative stress3. The aim of this study was to determine if a link exists between inadequate dietary antioxidant intake in older, physically active and inactive, male adults and vascular endothelial health. 
Methods: Thirteen physically active older adult males (age 66±5 years), 12 sedentary age matched males (age 69±6 years) consented to the study. Participants were interviewed to collect a 24-hour structured dietary recall and data were analysed using NetWISP dietary analysis software (Version 4.0, Tinuviel Software; Anglesey, UK). Vascular function was assessed using flow-mediated dilation (FMD) according to international guidelines4. A high-resolution ultrasound machine (Acuson P50, Siemens) was used; FMD was expressed as a percentage change of the brachial artery from baseline (Studio; Computer Vision Group). Data were tested for normality using Shapiro-W-Wilks tests. T-test was performed to compare the groups. Significance level was established at P<0.05 and data are expressed as mean ± standard deviation (SD). Results: FMD was lower in sedentary older adults versus the matched active participants (P<0.05; table). Dietary vitamin C and carotene consumption were also shown to be lower in the sedentary relative to the active group, yet within dietary guidelines (table). In contrast, dietary vitamin E intake was not different (P>0.05). 
Conclusions: The FMD response reported for the sedentary older adults was below the 7-10% identified as a normal healthy FMD response5. Furthermore, low intake of dietary antioxidants (vitamin C and carotene) may contribute, at least in part, to the observed reduction in vascular endothelial function. Despite dietary antioxidant consumption was not below the recommended guidelines, inadequate antioxidant vitamins intake may lead to excessive oxidative damage and has been associated with cardiovascular events. Is it time to review the guidelines?