The adoption of the adage "an apple a day keeps the doctor away" suggests that our “gut instinct” has speculated that apples confer a variety of health benefits.  Andrea Wilcks, from the University of Denmark's National Food Institute (Denmark), and colleagues engaged a lab animal model to investigate the effects of apple and apple product consumption on microbial balance in the digestive tract. The team fed the animals a diet of whole apples as well as apple-derived products such as apple juice and puree.  They found that the apples delivered a hearty dose of pectin, a type of dietary fiber present in apples, and consequently raised the amounts of “friendly bacteria,” that is -- those bacteria strains that are associated with improved intestinal health.  The team concludes that: “Our findings show that consumption of apple pectin (7% in the diet) increases the population of butyrate- and beta-glucuronidase producing Clostridiales, and decreases the population of specific species within the Bacteroidetes group.”