A Polyphenol Enriched Variety of Apple Alters Circulating Immune Cell Gene Expression and Faecal Microbiota Composition in Healthy Adults: A Randomized Controlled Trial

Abstract

Polyphenols within fruits and vegetables may contribute to health benefits due to their consumption, with the anthocyanin sub-set also adding colour. The Lemonade™ apple variety has green skin and white flesh, with low anthocyanin content, while some apple varieties have high anthocyanin content in both the skin and flesh. Effects of red compared with white-fleshed apples were studied in healthy human subjects in a randomized, placebo-controlled, cross-over intervention trial. Twenty-five healthy subjects consumed dried daily portions of the red-fleshed or placebo (white-fleshed) apple for two weeks, followed by one-week washout and further two-week crossover period. During the study, volunteers provided faecal samples for microbiota composition analysis and blood samples for peripheral blood mononuclear cell (PBMC) gene expression analysis. Subtle differences were observed in the faecal microbiota of subjects that were fed the different apples, with significant (p < 0.05) reductions in relative abundances of Streptococcus, Ruminococcus, Blautia, and Roseburia, and increased relative abundances of Sutterella, Butyricicoccus, and Lactobacillus in subjects after consuming the red apple. Changes in PBMC gene expression showed 18 mRNA transcripts were differentially expressed between the two groups, of which 16 were immunoglobulin related genes. Pathway analysis showed that these genes had roles in pathways such as immunoglobulin production, B cell-mediated immunity, complement activation, and phagocytosis. In conclusion, this study shows that anthocyanin-rich apples may influence immune function compared to control apples, with changes potentially associated with differences in the faecal microbiota.

Fruit and Vegetable Supplemented Diet Modulates the Pig Transcriptome and Microbiome after a Two-Week Feeding Intervention

“…This gene expression pattern suggests that B cell number/function was positively affected by an FV-supplemented diet. In support of our observations, a polyphenol-rich variety of apples provided in the diet to healthy adults was also shown to induce changes in peripheral blood mononuclear cells (PBMC) gene expression with differential regulation of immunoglobulin-related genes that had roles in immunoglobulin production and B-cell mediated immunity [75]. Significant changes in the expression of genes associated with immune-related pathways were also detected in adults at risk of developing metabolic syndrome who received a freeze-dried blueberrysupplemented diet [76], thus demonstrating that controlled nutritional interventions have the potential to affect health through immune response modulation.…”

Anthocyanins in Colorectal Cancer Prevention Review

“…In the mouse model, bileberry anthocyanins reduced the ratio of Firmicutes/Bacteroidetes (F/B), and increased Akkermansia and Parabacteroides [104]. In human clinical trials, anthocyanin-rich apple products increased Sutterella, Butyricicoccus, and Lactobacillus and reduced Streptococcus, Ruminococcus, Blautia, and Roseburia [105]. More research is needed to better understand how anthocyanins modulate the gut microbiota and thus regulate their bioavailabilities and antitumor activities.…”

Red-Fleshed Apples Rich in Anthocyanins and White-Fleshed Apples Modulate the Aorta and Heart Proteome in Hypercholesterolaemic Rats: The AppleCOR Study

“…Moreover, red-fleshed apple supplementation in rats has ben related with protective effects against colon carcinogenesis [ 15 ]. Furthermore, in humans, ACN rich red-fleshed apples has been observed effects on immune function compared to poor ACN apples, and these changes were potentially associated with differences in the faecal microbiota [ 16 ].…”