ANTIPROLIFERATIVE EFFECTS OF YOGURT FRACTIONS OBTAINED BY MEMBRANE DIALYSIS ON CULTURED MAMMALIAN INTESTINAL-CELLS

The consumption of yogurt has been associated with a reduced incidence of colon cancer in population groups. Bioactive peptides produced dur ing bacterial fermentation may alter the risk of colon cancer via modi fication of cell proliferation in the colon. Using our previously desc ribed cell culture model system, we have isolated a yogurt fraction th at decreases cell proliferation. Yogurt was fractionated using 10,000- and 500-Da membrane dialysis. When the yogurt fraction was incubated with IEC-6 or Caco-2 cells, cell division was decreased compared with control treatments, as determined by thymidine incorporation. Cell div ision was not inhibited in response to a similarly produced milk fract ion or in response to solutions of lactic acid. The determination of c ell kinetics by flow cytometry revealed a decrease in the number of ce lls in the initial growth phase in response to the yogurt fraction for the IEC-6 cells, but not the Caco-2 cells. alpha-Lactalbumin inhibite d cell division of both cell lines, but beta-casein did not.