Research has clarified which effective and beneficial components of raspberry actually reach the colon after digestion. In addition, it has been shown through an ex vivo digestion process, that is, in a real digestion, that its consumption contributes to the protection of cells against colorectal cancer.
The study is the work of a research team from IFAPA ‘Alameda del Obispo’ of Córdoba (Spain) together with other centers in the United Kingdom, Italy and Saudi Arabia.
Various analyzes have determined the presence in the colon of raspberry polyphenols, compounds with antioxidant and anti-inflammatory action. In addition, they show that they play a protective role against colorectal cancer due to their activity against stress and cell death. In the study ‘Ex vivo fecal fermentation of human ileal fluid collected after raspberry consumption modifies (poly) phenolics and modulates genoprotective effects in colonic epithelial cells’ published in the academic journal Redox Biology, scientists show that these substances act after intestinal digestion avoiding the oxidative stress of the cells and, therefore, their death.
In this way, they provide a more precise justification for including this red fruit in the recommended foods in the diet to prevent colon cancer, the one with the highest incidence in the population. “We have determined the exact proportion of the compounds that reaches the colon after digestion. In addition, we have verified in cell cultures that microbial action transforms certain molecules, initially present in raspberry, into phenolic acids that exert beneficial action in the body ”, the IFAPA researcher ‘Alameda del Obispo’ of Córdoba tells the Discover Foundation Gema Pereira-Caro, co-author of the study.
In the study, the metabolites and catabolites of raspberry polyphenols, that is, all their derivatives, were evaluated with greater precision and accuracy in a physiologically relevant context, since it develops in an ex vivo environment, that is, with a real human digestion.
The consumption of raspberry has been shown to contribute to the protection of cells against colorectal cancer. (Photo: Discover Foundation)
Simulated digestion procedures cannot completely mimic the process that takes place in the body due to the difficulty of replicating the number of enzymes involved and the multiple reactions that occur. Nor can the components be studied in the same real process, since a surgical intervention would be necessary in a healthy patient.
After consumption of raspberries, polyphenols that survive digestion in the small intestine enter the colon, where they are subject to microbial action. The objective of the research was to know the degradation and action of these compounds at that time. On some occasions, the data obtained through laboratory simulations do not offer the necessary accuracy to fully understand the specific action of this fruit. In this case, the studies have been carried out working with patients who had already had a colostomy. In this way, a greater precision in the results has been achieved.
Studies have included the analysis of the digested mass that comes from the ileum, called ileal fluid, extracted from the bags of patients without colon. It includes the antioxidant compounds of raspberry not absorbed by the small intestine.
In a person without this pathology, this digest would reach the colon, where bacteria, also known as the intestinal microbiota, would degrade it. The resulting nutrients pass into the bloodstream but, at the same time, act beneficially protecting the cells of the intestinal wall.
After determining the compounds that are formed during digestion, the experts subjected the ileal fluid samples to fecal fermentation to replicate what would occur in the colon in healthy subjects. Thus, the substances produced were analyzed to detect changes in the chemical composition, specify the activity of these compounds in protection against DNA damage and learn about the activation of Nrf2-ARE, a protein with high antioxidant power. In this way it is established with precision what exact component results and how it acts in the cells in the last part of the intestinal tract.
One of the groups of substances analyzed are anthocyanins, compounds that belong to the group of flavonoids. “They are those that give the red color to raspberries and have a high antioxidant, anti-inflammatory and anticancer power,” says the researcher.
This ex vivo study has shown that they remain in the ileal fluid and are transformed by the intestinal microbiota. This causes a significant increase in the total concentration of phenolic and aromatic compounds available after digestion to act in the colon.
In addition, the benefits of the action of these phenolic compounds derived from the digestion of anthocyanins have been observed in the analyzed tissues, since the expression of some genes involved in the prevention of colon cancer is increased or decreased while in patients colostomized did not occur. This highlights the importance of colonic digestion in the transformation of these bioactive compounds in raspberries.
This research has been funded through the Seventh Framework Program of the European Union, with the ‘Bachberry’ project, the Ministry of Science and Innovation, the National Processed Raspberry Council of the United States Ministry of Agriculture, the Division of Analytical and Scientific Services of the Environment (RESAS) of the Government of Scotland and King Saud University of Saudi Arabia. (Source: Discover Foundation)