A study from the University of Denmark’s National Food Institute gives some nice scientific backing to the old adage about apples keeping one healthy and doctor−free. The research was published in the journal BMC Microbiology.
The team led by Tine Rask Licht fed whole apples, or other products derived from apples (like apple puree and apple juice), to rats. They then monitored the levels of “good” bacteria in the rats’ intestines, using genetic – rather than culture – methods to confirm the bacteria’s presence. The team looked at a compound called 16S rRNA, which is specific to bacteria and varies according to the particular bacterial strain, allowing the researchers to identify presence of a strain more easily. Says Licht, “[b]y working out the sequences of 16S rRNA molecules in the rats' intestines and matching these to known bacterial profiles of 16S rRNA, we could determine which microorganisms were abundant in each group of rats.”
What about apples might lead to this change? The researchers attribute the finding to the pectin in apples, which is an element of the apple’s dietary fiber.
The beneficial bacteria of the gut are known to help with digestion and have previously been associated with lower risk of certain diseases, like colon cancer.
Coauthor Andrea Wilcks said that "[i]t seems that when apples are eaten regularly and over a prolonged period of time, these bacteria help produce short−chain fatty acids that provide ideal pH conditions for ensuring a beneficial balance of microorganisms. They also produce a chemical called butyrate, which is an important fuel for the cells of the intestinal wall.”
More research will be needed to ascertain whether the findings will hold true for humans as well. In the meantime, it can’t hurt to add an apple or two to the diet while we await the verdict.