Sucrose acetate isobutyrate (SAIB): historical aspects of its use in beverages and a review of toxicity studies prior to 1988.

Sucrose acetate isobutyrate (SAIB), a mixture of esters of sucrose with a composition approximating the name sucrose diacetate hexaisobutyrate, has been used for over 30 yr in many countries as a 'weighting' or 'density-adjusting' agent in non-alcoholic carbonated and non-carbonated beverages. As part of the demonstration of safety of SAIB as a direct food additive in human diets, a program of toxicity testing was started in the late 1950s that culminated in extensive studies of SAIB in rodents, monkeys and humans over the last decade. This review summarizes the toxicity data, accrued up until 1988, that precede the safety studies published elsewhere in this issue. SAIB has been shown to have very low acute and chronic toxicities in rats, monkeys, and, except for effects on the liver, in dogs at feeding levels of up to 10% in the diet. Slight effects seen in rats and monkeys at levels of 10% in the diet are unlikely to be directly caused by exposure to SAIB. In dogs, however, SAIB causes decreases in bromosulfophthalein (BSP) and indocyanine green (ICG) elimination from the serum immediately following a single dose, indicative of interference with biliary excretion. On repeated feeding in dogs, SAIB caused increases in serum alkaline phosphatase levels, but enzymes indicative of toxic effects on the liver were unaffected. On prolonged feeding to dogs, SAIB caused changes in liver morphology revealed by electron microscopy. All of these effects were reversed when SAIB was withdrawn from the diet. The no-effect level for these effects in dogs was near 5 mg/kg body weight, but these effects were not seen in rats fed up to 4 g/kg body weight/day, monkeys fed up to 10 g/kg body weight/day, or humans fed up to 20 mg/kg body weight/day. The toxicity and pharmacological studies in dogs, rats and monkeys suggest that the effect of SAIB on biliary excretion and liver morphology in dogs is essentially pharmacological rather than toxicological in nature and that the difference between the effects in dogs at levels as low as 5 mg/kg body weight/day, and the lack of effects in rats or monkeys at levels up to 10 g/kg/day is not merely a quantitative difference between species, but an absolute qualitative difference.