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Effect of indigestible fraction from different European Diets on the regulation of intestinal microflora; relationship with colorectal cancer protection

Final Activity Report Summary - EIFED.RIM.CRCP (Effect of indigestible fraction from different European diets on the regulation of intestinal microflora; relationship with ... cancer protection)

The development of chronic and degenerative diseases, such as cancers and cardiovascular diseases, has been associated with oxidative stress. Free radical species generated by normal human metabolism are main responsible of this stress. These reactive species may cause damages in important molecules as lipids, proteins and DNA producing cellular injury. Dietary antioxidants may play an important role in counterbalance these attacks. Therefore, the antioxidant capacity of a whole diet could be a parameter useful to define a healthy diet.

Preliminary phases of this study where based in the comparison of the antioxidant capacity in the whole diets of two European regions with high and low prevalence of colorectal cancer and cardiovascular diseases. The food consumption reported by the European Prospective Investigation into Cancer and Nutrition (EPIC) for Murcia (Spain) and Copenhagen (Denmark) were used as Mediterranean and Scandinavian diets respectively. It was estimated that the daily antioxidant intake in Murcia is a 20 % higher than in Copenhagen.

By other hand, plant foods provided fibre and other non-digestible compounds, named as a whole Indigestible Fraction. It escapes digestion and intestinal absorption, reaching the colon where feeds the commensal bacteria, providing advantages normally related to prebiotics foods, such as increase calcium absorption, improve immune system and keep an optimal intestinal health. Other properties of indigestible fraction are related to transit regulation and to scavenge and remove toxic products. Also, antioxidant compounds linked to indigestible fraction may be released by the bacterial metabolism keeping an antioxidant environment, important in the prevention of cellular carcinogenesis.

The indigestible fraction from both diets, Murcia and Copenhague, was in vitro obtained, analysed and compared. It was estimated that diet of Murcia provides 20 % more indigestible fraction than the diet of Copenhagen. Also the composition is different, been the indigestible fraction from Murcia richer in polysaccharides potentially degradable by colonic bacteria.

Based on these results, we can conclude that the higher intake of antioxidants and indigestible fraction in the diet of Murcia may be a factor related to lower rate of diseases, such as cardiovascular diseases and certain kind of cancers. In order to reaffirm this conclusion, further research will be done using the indigestible fraction from both diets as fermentative substrate to grow certain kind of colonic bacteria strains. The fermentation products will be analysed. Supernatants of these fermentations will be added to media used to culture colonic epithelial cells. We expect to observe a positive relation between the amounts of indigestible fraction, bacterial growth and genomic cellular stability.