An apple a day keeps the doctor away !

Friday, 13 January 2012 16:35

Nutrition News

Might the old saying “an apple a day keeps the doctor away” actually be true? 

This is what recent work by an American team seems to demonstrate.  They studied the effects of polyphenol extracts taken from apple peels upon regulation of intestinal inflammation.  For that purpose, the researchers used an experimental model of chemically induced colitis in laboratory mice.  Via   oral ingestion, they administered either a placbo or varying doses of apple polyphenols to the different groups of mice  before and during development of colitis.  Their results demonstrate that mice that received polyphenols developed much less severe colitis or had no symptoms at all.  The researchers next identified the cell target of these polyphenols. It is a particular cell type implicated in immune defenses, and which is abnormally overactive in chronic inflammatory bowel diseases (IBDs):  the T lymphocyte.  In mice that were genetically engineered to get rid of T cells, polyphenols were no longer able to regulate inflammation, thereby demonstrating that they protect against gut inflammation via control of T lymphocyte activity. 

Recently, two other studies published in the prestigious journals Science and Cell also demonstrated a very strong association between phytonutrients present in the Cruciferae family of vegetables (cabbage, broccoli, Brussel sprouts, etc.) and normal development of the gut  immune system.  Those two studies characterized the molecular target of these vegetal components in the gut (a protein called the aryl hydrocarbon receptor, or AhR), thereby identifying a promising therapeutic target for control of the intestinal immune response in patients with IBD.

References :

- Apple polyphenols require T cells to ameliorate dextran sulfate sodium-induced colitis and dampen proinflammatory cytokine expression.Skyberg, JA et al. Journal of leukocyte biology, December 2011, Volume 90 ; 1043-1054

- Natural aryl hydrocarbon receptor ligands control organogenesis of intestinal lymphoid follicles.Kiss, EA et al. Science 27 oct 2011

- Exogenous stimuli maintain intraepithelial lymphocytes via aryl hydrocarbon receptor activation.Li, Y et al. Cell 147. 629-640 (2011)