New research has suggested that different food matrixes may affect the bioavailability of polyphenols in the colon. The study, published in Molecular Nutrition & Food Research, finds that apple smoothies deliver a higher quantity of bioavailable polyphenols to the colon than apple juices or ciders, and may therefore be more effective in the prevention of chronic colon diseases than both cloudy apple juice and apple cider.
“This might indicate a higher preventive potential of apple smoothies against chronic colon diseases compared to cloudy apple juice and cider,” said the researchers, led by Stephanie Hagl from the Division of Food Chemistry and Toxicology, University of Kaiserslautern, Germany.
Polyphenol protection
Apples have been suggested to have significant cancer preventive effects. Possible apple constituents responsible such positive effects may include vitamins, minerals and secondary plant compounds like polyphenols.
Polyphenols are known to exhibit antioxidative and anti-inflammatory effects, “therefore, polyphenols are likely to play an important role in the cancer preventive potential of apples,” wrote Hagl and colleagues.
They noted that although many studies have demonstrated protective effects of apple constituents or apple juice extracts in vitro, it is difficult to transfer such results to in vivo situations, since factors such as bioavailability and metabolism have to be taken into account.
It is therefore important to know how much of each class of polyphenols ingested are absorbed from the gastrointestinal tract and how much reach the colon. To determine the amount of polyphenols reaching the colon, studies with ileostomy (a collecting pouch from the small intestine) can be used, as it can be assumed that substances detected in the ileostomy bags would reach the colon in healthy human subjects.
The aim of this study was to determine the amounts of polyphenols and quinic acid reaching the ileostomy bags (reflecting the colon in healthy humans) after ingestion of apple smoothie, a beverage containing 60 percent cloudy apple juice and 40 percent apple puree or cider.
Study details
Ileostomy bags were collected directly before and 1, 2, 4, 6 and 8 hours after consumption of the beverages, and the polyphenol and quinic acid contents of the ileostomy fluids were examined.
The amounts of polyphenol and quinic acids reaching the ileostomy bags were found to be considerably higher after apple smoothie consumption than after the consumption of cloudy apple juice or cider.
The overall recovery of ingested polyphenols and quinic acid in the ileostomy bags for the smoothie drink was found to be just over 63 percent, whilst just over 70 percent of quinic acid was recovered in the ileostomy bags.
Hagl and colleagues concluded that substantially more polyphenols and quinic acid reached the ileostomy bags (the colon of healthy individuals) after consumption of apple smoothie compared to cloudy apple juice or cider, and therefore may have greater potential for preventing against colon diseases.
They speculated that the reason for such differences in bioavailability of polyphenols and quinic acid in the small intestine and colon after consumption of the three beverages may be related to the differences in the amounts of cell wall constituents which may reduce polyphenol metabolism.
“The apple smoothie contains much more of these matrix components than both apple juice and cider, hence they probably bind more polyphenols and thus reduce the bioavailability of the substances in the small intestine,” wrote Hagl and co workers.
Source: Molecular Nutrition & Food Research
Published online ahead of print, doi: 10.1002/mnfr.201000252
“Colonic availability of polyphenols and D-(−)-quinic acid after apple smoothie consumption”
Authors: S. Hagl, H. Deusser, B. Soyalan, C. Janzowski, F. Will, H. Dietrich, et al.