Select Committee on GRAS Substances (SCOGS) Opinion: Hydroxypropyl Distarch Glycerol
Hydroxypropyl Distarch Glycerol
- SCOGS-Report Number: 115*
- Type Of Conclusion: 4
- ID Code: 59419-60-2
- Year: 1979
- 21 CFR Section:
Included in this group of modified starches are distarch glycerol, hydroxypropyl distarch glycerol, acetylated distarch glycerol, and succinyl distarch glycerol. No adverse effects were observed in short -term rat feeding studies with distarch glycerols cross-linked by treatment with almost twice the permitted level of epichlorohydrin (0.5 percent as compared to 0.3 percent) and fed at levels (60 g per kg) much greater than probable human intake.
Cecal enlargement appeared to be the only significant change observed in short-term rat feeding studies with hydroxypropyl distarch glycerols in which the modified starch was fed at levels up to 25 g per kg; no significant changes were noted in similar studies with dogs fed at levels up to 4 g per kg. In a long-term rat feeding study weight gain was reduced in females at the highest feeding level but necropsy revealed no change except for cecal enlargement and renal calcification accompanied by focal hyperplasia of the pelvic epithelium. No histological abnormality was associated with the former change and it is considered to have no toxicological significance. The latter condition was most marked in males but was not clearly dose related. A three-generation reproduction study revealed no adverse effects of feeding this modified starch.
Short-term and long-term rat feeding studies with acetylated distarch glycerol revealed no abnormalities in gross or histopathological findings. No adverse effects were observed in a three-generation reproduction test. Growth rate was somewhat reduced in males in the short-term study at the high dietary level fed (40 g per kg) but not at the level (30 g per kg) fed in the long-term study. Kidney lesions characterized by focal hyperplasia of the epithelium lining the urinary space accompanied by calcified deposits on the lining of the epithelium were present in both control and treated animals. The Select Committee considers these lesions observed with both the hydroxypropyl and acetyl distarch glycerols to be of doubtful biological importance but suggests that studies be undertaken in due time to determine their toxicological significance.
A 90-day feeding study of succinyl distarch glycerol showed no abnormalities attributable to diets in blood analyses, gross or histopathological findings. Growth rate was somewhat reduced in males but this result is of doubtful significance in view of the high dietary level (50 g per kg) fed. However, the Select Committee considers that additional information should be obtained on the chronic toxicity of succinyl distarch glycerol or the related modified starch, sodium starch succinate.
Although there is no evidence of adverse effects resulting from unreacted epichlorohydrin or its reaction by-products in the distarch glycerols, the mutagenic properties of epichlorohydrin and the indication that it induces cancer of the respiratory system in animals on exposure by inhalation, and local sarcomata by subcutaneous injection, suggests that this substance may also be carcinogenic when ingested in food. Although analyses reported for starches cross -linked with epichlorohydrin showed no detectable residue and two long-term feeding studies of the treated starches gave no evidence of carcinogenicity, it would be prudent to discontinue use of such cross-linked starches in foods until animal feeding experiments with graded levels of epichlorohydrin have been carried out. It is understood that industry has voluntarily adopted this precaution.
On basis of the above evidence, the Select Committee concludes that:
The evidence on distarch glycerol, hydroxypropyl distarch glycerol, acetylated distarch glycerol, and succinyl distarch glycerol is insufficient to determine that the adverse effects reported are not deleterious to the public health should they be used at former levels and in the manner formerly practiced.