The gut microbiota and cardiovascular health benefits: a focus on wholegrain oats

Existing scientific data suggest that a high intake of wholegrain foods contributes to improved gut health and a reduced risk of cardiovascular disease. Wholegrain oats are rich in dietary fibre and an important source of many bioactive components, including minerals, vitamins and phenolic compounds. The oat β‐glucans have been reported to lower low‐density lipoprotein cholesterol through their ability to increase the viscosity of intestinal chime, change the gut microbiota composition and increase the production of short‐chain fatty acids, which may contribute to the inhibition of hepatic cholesterol synthesis. Oats are also a rich source of phenolic acids, which are predominantly bound to cell wall polysaccharides through ester bonds. This bound state within oats means that phenolic acid bioavailability will largely be determined by interactions with the colonic microbiota in the large intestine. However, results from in vitro, animal and human studies have been inconsistent in relation to the impact of oats on the gut microbiota, possibly due to differences in experimental techniques and because compounds in oats, other than β‐glucans, have not been considered. This review focuses on the interaction of oat β‐glucans and phenolic acids with gut microbiota, and the subsequent link to cardiovascular health.