| Summary: | While health promotion literature and clinical guidelines suggest eating 5 or more portions of fruit and vegetables daily may have beneficial vascular effects, this specific hypothesis has rarely been addressed during randomised control trials in fteeliving volunteers. We conducted such a study among individuals with mild to moderate hypertension. During a common 4 week run-in period all participants limited their fruit and vegetable consumption (l portionfday) before randomisation to 1. 3 or 6 portions daily for the ne:x1. 8 weeks. Volunteers attended a research centre for vascular assessment immediately before and after the intervention phase. Forearm blood flow responses to an endothelium-dependent agonist (acetylcholine) were estimated by venous occlusion plethysmography while carotid-radial pulse wave velocity (CRPWV) and the aortic augmentation index were derived from applanation tonometry. Pre and post intervention circulating micronutrient concentrations were compared with contemporaneously recorded 4-day food records. A total of 117 volunteers (mean age ± standard deviation, 54.l±7.8 }years), completed the 12 week trial. At baseline a significant negative relationship was noted between maximum forearm blood flow response to intra-arterial acetylcholine and CRPWV (r= -O.225~ p=O.0l6). Changes in reported fruit and vegetable consmnption correlated significantly with altered circulating concentrations offJ-crypthoxanthin (F0.350, p<O.OOl ),lutein (r=O.347~p<O.OOl) and ascorbic acid (r=O.256, p=O.013). Increased fmit and vegetable consumption over an 8 week period was associated with significant improvements in ma\immn forearm blood flow response to acetylcholine (change +6.30% per extra additional portion daily, 95% cr 0.60%-12.30%, p--Q.032). No significant intervention-related changes were seen in pulse wave-derived indices or biochemical markers ofinflammation and oxidative stress. These findings relate an emerging mechanical arterial descriptor to an established measure of <endothelial function', suggest that circulating fl-cr)'pthoxanthin, lutein and ascorbic acid are useful biomarkers during dietary intervention work and link increased fruit and vegetable consumption with improved arterial health.
|
|---|
