Increased bioavailability of phenolic acids and enhanced vascular function following intake of feruloyl esterase-processed high fibre bread: A randomized, controlled, single blind, crossover human intervention trial

Background & aims: Clinical trial data have indicated an association between wholegrain consumption and a reduction in surrogate markers of cardiovascular disease. Phenolics present in wholegrain bound to arabinoxylan fibre may contribute these effects, particularly when released enzymatically from the fiber prior to ingestion. The aim of the present study was therefore to determine whether the intake of high fibre bread containing higher free ferulic acid (FA) levels (enzymatically released during processing) enhances human endothelium-dependent vascular function. Methods: A randomized, single masked, controlled, crossover, human intervention study was conducted on 19 healthy men. Individuals consumed either a high fibre flatbread with enzymatically released free FA (14.22 mg), an equivalent standard high fibre bread (2.34 mg), or a white bread control (0.48 mg) and markers of vascular function and plasma phenolic acid concentrations were measured at baseline, 2, 5 and 7 h post consumption. Results: Significantly increased brachial arterial dilation was observed following consumption of the high free FA ('enzyme-treated') high fibre bread verses both a white bread (2 h: p < 0.05; 5 h: p < 0.01) and a standard high fibre bread (5 h: p < 0.05). Concurrently, significant increases in plasma FA levels were observed, at 2 h (p < 0.01) after consumption of the enzyme-treated bread, relative to control treatments. Blood pressure, heart rate, DVP-SI and DVP-RI were not significantly altered following intake of any of the breads (p > 0.05). Conclusion: Dietary intake of bread, processed enzymatically to release FA from arabinoxylan fiber during production increases the bioavailability of FA, and induces acute endothelium-dependent vasodilation. Clinical trial registry: No: NCT03946293. Website: www.clinicaltrials.gov. (c) 2020 Published by Elsevier Ltd.

Automated summary

In this study, intake of high fiber bread containing higher levels of free ferulic acid was found to enhance human endothelium-dependent vascular function by increasing vascular dilation to improve cardiovascular health. Enzymatically processed high fiber bread releasing FA also increased the bioavailability of FA.