There is now considerable scientific evidence that a diet rich in fruits and vegetables can improve human health and protect against chronic diseases. However, it is not clear whether different fruits and vegetables have distinct beneficial effects. A paper in Nutrients published in May 2015 helps to tease apart some of the key mechanisms involved related to the consumption of apples.
Apples are among the most frequently consumed fruits and a rich source of polyphenols and fibre. A major proportion of the bioactive components in apples, including the high molecular weight polyphenols, escape absorption in the upper gastrointestinal tract and reach the large intestine relatively intact.
There, they can be converted by the colonic microbiota to bioavailable and biologically active compounds with systemic effects, in addition to modulating microbial composition. Epidemiological studies have identified associations between frequent apple consumption and reduced risk of chronic diseases such as cardiovascular disease. Human and animal intervention studies demonstrate beneficial effects on lipid metabolism, vascular function and inflammation but only a few studies have attempted to link these mechanistically with the gut microbiota.
This review will focus on the reciprocal interaction between apple components and the gut microbiota, the potential link to cardiovascular health and the possible mechanisms of action.
 Koutsos A, Tuohy KM, Lovegrove JA. Apples and Cardiovascular Health-Is the Gut Microbiota a Core Consideration? Nutrients. 2015 May 26;7(6):3959-3998 View Full Paper