Safety assessment of γ-cyclodextrin

Gamma-cyclodextrin (γ-CD) is a cyclic α-(1,4)-linked oligosaccharide consisting of eight glucose molecules. Like other cyclodextrins, γ-CD can form inclusion complexes with a variety of organic molecules because the inner side of the torus-like molecule is less polar than the outer side. In foods, γ-CD may be used as a carrier for flavors, vitamins, polyunsaturated fatty acids, and other ingredients. It also has useful properties as a stabilizer in different food systems. The daily intake from all its intended uses in food at highest feasible concentrations has been estimated at 4.1 g/person/day for consumers of γ-CD containing foods. The present review summarizes the safety data of γ-CD. The toxicity studies consist of standard genotoxicity tests, subchronic rat studies with oral and intravenous administration of γ-CD for up to 3 months, a subchronic (3-month) toxicity study in dogs, a (1-year) oral toxicity study in rats, and embryotoxicity/teratogenicity studies in rats and rabbits. In the studies with oral administration, γ-CD was given at dietary concentrations of up to 20%. All these studies demonstrated that γ-CD is well tolerated and elicits no toxicological effects. Metabolic studies in rats showed that γ-CD is rapidly and essentially completely digested by salivary and pancreatic amylase. Therefore, the metabolism of γ-CD closely resembles that of starch and linear dextrins. A human study with ingestion of single doses of 8 g γ-CD or 8 g maltodextrin did not reveal a difference in gastrointestinal tolerance of these two products. An interaction of ingested γ-CD with the absorption of fat-soluble vitamins or other lipophilic nutrients is not to be expected because the formation of inclusion complexes is a reversible process, γ-CD is readily digested in the small intestine, and studies with β-CD, a non-digestible cyclodextrin, have shown that the bioavailability of vitamins (A, D, and E) is not impaired. On basis of these studies it is concluded that γ-CD is generally recognized as safe (GRAS) for its intended uses in food.