Isomaltulose (Palatinose): a review of biological and toxicological studies.

Isomaltulose is a natural occurring disaccharide composed of alpha-1,6-linked glucose and fructose. Commercial isomaltulose is produced from sucrose by enzymatic rearrangement and has been used as a sugar in Japan since 1985. It is particularly suitable as a non-cariogenic sucrose replacement and is favorable in products for diabetics and prediabetic dispositions. In vivo studies with rats and pigs indicate that isomaltulose is completely hydrolyzed and absorbed in the small intestine. This is supported by in vitro studies showing that intestinal disaccharidases from various species (including man) can hydrolyze isomaltulose. The rate of hydrolysis, however, is very slow compared with sucrose and maltose. Thus, blood glucose and insulin levels in humans after oral administration rise slower and reach lower maxima than after sucrose administration. After absorption, fructose and glucose are metabolized as typical for these monosaccharides. From intravenous studies it can be assumed that any systemic isomaltulose would be hydrolyzed as well, or excreted in urine. In several subchronic toxicity studies, the administration of large doses (up to 7.0 and 8.1 g/kg body weight/day in male and female rats, respectively) of isomaltulose, did not result in adverse effects. Isomaltulose induced neither embryotoxic or teratogenic effects in rat foetuses, nor maternal toxicity at levels up to 7 g/kg body weight/day. Isomaltulose was non-mutagenic in the Ames test. As hydrolysis in the small intestine is complete, even high levels of isomaltulose are well tolerated in animals and humans. In studies with healthy as well as diabetic subjects high doses up to 50 g were tolerated without signs of intestinal discomfort. On the basis of the data reviewed it is concluded that the use of isomaltulose as an alternative sugar is as safe as the use of other digestible sugars consisting of glucose and fructose.

13-Week oral toxicity study with isomaltulose (Palatinose) in rats.

The potential subchronic oral toxicity of isomaltulose (Palatinose) was examined by administering this substance in the diet to groups of 20 male and 20 female Wistar rats at levels of 0, 2.5, 5 and 10% for 13 consecutive weeks. Daily clinical observations, body weight, food conversion efficiency, food and water consumption were not affected at any stage of the study. Ophthalmoscopy, haematology, clinical chemistry, urinalysis, organ weights, gross and histopathological examination, neurobehavioural observations, motor activity assessment and the results of an immunotoxicity screen did not reveal any abnormalities related to the ingestion of the test substance. In conclusion, the administration of isomaltulose at dietary levels up to 10% for 13 consecutive weeks was well tolerated without any signs of toxicity. The overall intake at this level corresponded to 7.0 and 8.1 g/kg body weight/day in male and female rats, respectively.

Embryotoxicity/teratogenicity study with isomaltulose (Palatinose) in rats.

The embryotoxicity/teratogenicity of the natural sweetener isomaltulose (Palatinose) was studied in Wistar rats. Groups of 24 mated females were fed diets containing isomaltulose at levels of 0, 2.5, 5 and 10% from day 0 to day 21 of pregnancy. The dams were killed on day 21 of pregnancy. No maternal toxicity occurred and no effects on reproductive performance, nor on embryonic or foetal development, including visceral and skeletal examination, were seen in any of the groups fed isomaltulose. The dietary level of 10% isomaltulose was equivalent to about 7 g/kg body weight/day.