1990 Volume 31 Issue 5 Pages 394-403_1
The sweetening agents isomaltooligosaccharides (IMO), derived from cornstarch, are known to be a growth factor of Bifidobacterium. The biological effects of IMO on peripheral blood lymphocytes and on the composition of intestinal microflora, and the chronic toxicity were investigated. Male Wistar rats were fed ad libitum with drinking water containing 3% IMO for 12 months. Furthermore, an acute oral toxicity test using male Wistar rats, a mutagenicity test by Ames' method, and a chromosome aberration test using Chinese hamster lung (CHL) cells were carried out. The results may be summarized as follows. (1) The intake of IMO by the rats in long-term studies was estimated to be 2.7 to 5.0g/kg/day. (2) The absolute number of peripheral blood lymphocytes was increased remarkably without increase in that of white blood cells at one and three months after the start of the study. (3) Stimulation of Bifidobacterium growth and suppression of Clostridium growth were observed during the study for 12 months. (4) No adverse effect of IMO feeding was observed in treated rats as regards the body weight, blood biochemical and hematological tests, and anatomical and histopathological examinations. (5) The oral LD50 value of IMO was estimated to be more than 44.0g/kg. (6) Neither mutagenicity in Salmonella typhimurium TA98, TA100, TA1535 or TA1537, or Escherichia coil WP2uvrA-, nor chromosome aberration in CHL cells was observed.