Fibre binds up to 80 percent of cancer-inhibiting antioxidant polyphenols in fruit and vegetables, thereby protecting the antioxidants from early digestion in the stomach and small intestine, the study found.
Anneline Padayachee at the University of Queensland and the Commonwealth Scientific and Industrial Research Organisation found that fibre acts as an antioxidant trafficker by safely transporting antioxidant nutrients to the colon where they provide protection against cancers like colon cancer.
Antioxidants are substances that may protect your cells against the effects of free radicals, molecules produced when your body breaks down food. They can damage cells, and may play a role in heart disease, cancer and other diseases.
"Cells in fruits and vegetables are 'opened' allowing nutrients to be released when they are juiced, pureed or chewed," Padayachee said, according to a Queensland statement.
"In an unexpected twist, I found that after being released from the cell 80 percent of available antioxidant polyphenols bind to plant fibre with minimal release during the stomach and small intestinal phases of digestion."
"Fibre is able to safely and effectively transport polyphenols to the colon where these compounds may have a protective effect on colon health as they are released during plant fibre fermentation by gut bacteria."
This finding also has implications for fresh juice lovers who are throwing out antioxidants along with the fibre-rich pulp they discard.
Padayachee used black carrots, which are rich in two antioxidant polyphenols - anthocyanins and phenolic acids - as a model system in her research to assess why plant-based diets generally result in better gut health.