Flavonoid‐Rich Apple Improves Endothelial Function in Individuals at Risk for Cardiovascular Disease: A Randomized Controlled Clinical Trial

Nicola P. Bondonno, Catherine P. Bondonno, Lauren C. Blekkenhorst, Michael J. Considine, Ghassan Maghzal, Roland Stocker, Richard J. Woodman, Natalie C. Ward, Jonathan M. Hodgson, Kevin D. Croft

The cardioprotective effects of apples are primarily attributed to flavonoids, found predominantly in the skin. This study aimed to determine if acute and/or chronic (4 weeks) ingestion of flavonoid-rich apples improves endothelial function, blood pressure (BP) and arterial stiffness in individuals at risk for CVD. In this randomised, controlled cross-over trial, acute and 4 week intake of apple with skin (high flavonoid apple, HFA) was compared to intake of apple flesh only (low flavonoid apple, LFA) in 30 participants. The primary outcome was endothelial function assessed using flow-mediated dilation (FMD) of the brachial artery, while main secondary outcomes were 24 h ambulatory BP and arterial stiffness. Other outcomes included fasting serum glucose and lipoprotein profile, plasma haem oxygenase-1 (Hmox-1), F2 -isoprostanes, flavonoid metabolites, and plasma and salivary nitrate (NO3(-) ) and nitrite (NO2(-) ) concentrations. Compared to LFA control, the HFA resulted in a significant increase in FMD acutely (0.8%, p<0.001) and after 4 weeks chronic intake (0.5%, p<0.001), and in plasma flavonoid metabolites (p<0.0001). Other outcomes were not altered significantly. A lower risk of CVD with higher apple consumption could be mediated by the beneficial effect of apple skin on endothelial function, both acutely and chronically. This article is protected by copyright. All rights reserved.