ACETYLATED DISTARCH PHOSPHATE Explanation This substance was evaluated for acceptable daily intake for man (ADI) by the Joint FAO/WHO Expert Committee on Food Additives in 1969 and 1971 (see Annex I, Refs. 20 and 27). A toxicological monograph was issued in 1974 (see Annex I, Ref. 33). Since the previous evaluation, additional data have become available and are summarized and discussed in the following monograph. The previously published monograph has been expanded and is reproduced in its entirety below. Introduction Modification is usually performed by the use of up to 0.1% of phosphorus oxychloride and 5% acetic anhydride. Vinyl acetate may be used as an alternative acetylating agent. Maximum acetylation amounts usually to 2.5% acetyl groups. BIOLOGICAL DATA BIOCHEMICAL ASPECTS The digestibilities in vitro by pancreatin and porcine mucosal enzymes of acetylated distarch phosphates, modified to 1.6% and 2.3% acetyl content, were found to be 93% and 31%, respectively of that of unmodified starch (Leegwater, 1971). TOXICOLOGICAL STUDIES Special studies on kidney lesions associated with dietary modified starches Rat Groups of 25 female Sprague-Dawley rats were fed diets containing either 30% acetylated distarch phosphate or 30% unmodified starch (control) in a 1-year study with weanling rats (Experiment I) and a separate 9-month study utilizing 9-month-old rats (Experiment II). The Ca concentration in the diet was c. 1%, P concentration c. 0.8% and Mg c. 0.15%. Urinary calcium concentration and total daily output were significantly increased in animals on the test diet (Experiments I and II), but only minor differences occurred in phosphorus, oxalate, magnesium and creatinine excretion. No significant effects were observed on body weight, food consumption, urine volume, urine pH and crystal content or faecal mineral content in animals on the test diet. At autopsy, caecal enlargement was present in treated animals, but no other treatment-related effects on relative organ weights were observed. No treatment-related histopathological effects were observed in the uterus or lower urinary tract, liver, parathyroid, caecum or ovaries in either experiment. Histological examination of kidney sections demonstrated the presence of treatment-related pelvic nephrocalcinosis. An apparent correlation was observed between the increased incidence of pelvic nephrocalcinosis, increased accumulation of calcium in the kidney, and increased urinary excretion of calcium. Residues of calcium in kidney tissue were significantly higher in test groups than in control (Hodgkinson et al., 1981). Roe (1979) has conducted an extensive review of mineral deposition in the renal pelvis of rats and concluded that pelvic nephrocalcinosis, corticomedullary nephrocalcinosis, acute tubular nephropathy, and calculus formation are manifestations of mineral imbalance and are of relatively common occurrence in untreated laboratory rats (particularly older animals). Special studies on reproduction Rat A 3-generation study was performed using groups of 10 males and 20 females of the P, F1 and F2 generations to produce 2 successive litters in each generation by mating at weeks 12 and 20 after weaning. Ten males and 10 females of the F1b generation were kept for 3 weeks after weaning and then sacrificed for histopathological studies. The P, F1b and F2b parents were used for determination of implantation sites. The test material fed at 10% of the diet consisted of a starch modified with 8% acetic anhydride and 0.02% phosphorus oxychloride (D.S. of 0.093) and another starch modified with 4.5% vinyl acetate and 1.2% phosphorus oxychloride (D.S. of 0.064, 0.043% phosphorus introduced). No adverse effects were noted with respect to health, behaviour, mortality, growth, fertility, litter size, resorption quotient, weaning weight or mortality of young. Caecal weight of parent rats fed the modified starches was not increased. Gross pathology revealed a slightly decreased thyroid weight and a slightly increased caecum weight in F3a rats fed the starch treated with acetic anhydride and phosphorus oxychloride. Histopathology failed to reveal any treatment-related changes (De Groot et al., 1974). Weanling Wistar-derived rats were segregated by sex into groups of 10 males and 20 females and fed a test diet consisting of 10% acetylated distarch phosphate + 20% unmodified starch and a control diet of 30% unmodified starch throughout the pre-mating, gestation and lactation periods. Control animals received equivalent levels of unmodified starch in their diet. At weeks 12 and 20, all rats were mated in groups of 5 males and 10 females to produce 2 successive litters (F1a and F1b). Litters were randomly culled on day 1 to 8 pups when required. Ten male and 20 female weanlings were randomly selected from the F1b litter and the above procedure repeated to produce F2a and F2b litters. In similar fashion, male and female weanlings from the F2b generation were mated to produce F3a and F3b litters. After weaning their second litter, dams were sacrificed and the uterus examined for implantation sites. Ten male and 20 female weanlings were selected from the F3b litters and continued on their diets for 3 more weeks before sacrifice. No treatment-related differences in mortality or fertility were observed between the test groups and controls. The growth rate of the pups in all groups given acetylated distarch phosphate was comparable with that in the controls, and mortality in utero (resorption quotient) and preweaning mortality were low in all groups. The rats from the F3b generation, sacrificed 3-4 weeks after weaning, showed no treatment-related gross or histological changes (de Groot et al., 1974). Special studies Groups of 10 male and 10 female rats were fed 0, 25 or 50% of 2 different modified starches (acetic anhydride and vinyl acetate modified) in a low residue diet for 7 days followed by the additional feeding of 4% cellulose for 3 days. The body weights of animals fed 50% modified starch were somewhat lower than those of the controls. Production of faecal dry matter was increased in the higher groups and less so at the 25% level. Diarrhoea occurred at the higher level with both modified starches. The addition of 4% cellulose had no effect on the severity or frequency of the diarrhoea. At the higher level, there was also some loss of hair in both sexes (de Groot & Spanjers, 1970). Short-term studies Hamster Groups of 10 male and 10 female Syrian Golden hamsters, weighing 30-40 g, were fed a diet containing either 30% acetylated distarch phosphate or 30% untreated starch for 30 days. Hamsters fed the test diet exhibited a reduction in average daily weight gain, compared to control animals, but the average daily test diet intake was also reduced. Comparison of feed consumption to corresponding weight gain did not indicate a significant difference in efficiency of utilization of the test and control diets. No treatment-related differences were noted in haematology, clinical chemistry or urinalysis data. No treatment-related lesions were evident in histological sections from liver and kidney (Newberne & Buttolph, 1977). Rat Groups of 10 male and 10 female rats were fed 0, 25 and 50% of 2 different modified starches (acetic anhydride and vinyl acetate modified) in their diet for 8 weeks. Body weights of animals on the higher test levels were somewhat lower than at the 25% levels and also lower than controls in both sexes. However, the differences were not statistically significant. The faecal water content was variable and could not be related to dietary dosage levels. Production of faecal dry matter was increased in both sexes at the higher level tested and slightly so at the 25% dietary level. The incidence of diarrhoea was insignificant. A dose-related increase in caecal weight occurred in both sexes. No histological abnormalities of the enlarged caeca were noted (de Groot & Spanjers, 1970). Pig Groups of 4 male and 4 female pigs were given 0, 35 or 70% of modified starch in their diet over 14-1/2 weeks. Growth rate and food consumption were satisfactory. Haematology, blood chemistry and urinalysis revealed no treatment-related abnormalities. Ophthalmoscopy showed no abnormalities associated with the test substance. Organ weight, gross and histopathology revealed no abnormalities in test or control groups. Three pigs in the higher test group died suddenly at various intervals during the test without any evidence pointing to the cause of their death. One pig in the higher test group and another in the 35% group showed evidence of neurological malfunction. The animal on 70% test substance died, that on the lower dietary level recovered. No histological evidence of nervous system involvement was noted in these 2 or in any other animal (Shillam et al., 1971). A further pig study in which groups of 8 pigs were fed 0, 5, 15 and 25% modified starch in the diet for 14 weeks, showed no effect on growth, food consumption, haematology or biochemistry. One pig died of unknown cause. No significant abnormalities were found at post mortem but histology was not performed except in the animal which died (Shillam et al., 1973). Long-term studies Rat Groups of 30 male and 30 female rats were fed 2 different modified starches (acetic anhydride and vinyl acetate modified) at levels of 0, 5, 10 and 30% in their diet for 104 weeks. Appearance, behaviour, food consumption and mortality were not adversely affected nor was diarrhoea observed at any level with either modified starch. Haematology, serum chemistry and urinalysis revealed no effects related to treatment in any group. There was a dose-related increase in the caecal weight in both sexes at the 30% level but in males only at the 10% level. All other organ weights showed no treatment-related changes. No gross or microscopic pathological abnormalities were noted which could be related to the test substances or which would point to any carcinogenic effects or to any compound-related effects. The caeca appeared remarkably normal (Til et al., 1971a). Groups of 30 male and 30 female weanling Wistar-derived rats were fed diets containing 0, 5, 10 and 30% acetylated distarch phosphate and 30% unmodified starch (control) for 2 years. A slight growth retardation was observed at the 30% dietary level, with an increase in the relative weight of the caecum. The caecal enlargement was attributed to an adaptive response to the presence of indigestible material, rather than to a pathological response. Females exhibited an apparent dose-related increase in relative adrenal weight. Other organs exhibited slightly increased weight at higher dose levels, but these findings were, in most cases, considered incidental because histological sections revealed no treatment-related effects. The only treatment-related effect that was observed histologically was a kidney lesion which occurred at a higher incidence in the high dose males. The lesion consisted of focal hyperplasia of the renal papillary and pelvic epithelium accompanied by calcified patches in the underlying tissues. No treatment-related effect was observed on the pattern of neoplasm development, or on food intake, survival, haematology or clinical chemistry (de Groot et al., 1974). OBSERVATIONS IN MAN Twelve volunteers consumed on each of 4 successive days, 60 g acetylated distarch phosphates of either 1.5% or 2.33% acetyl content. No abnormalities were observed as regards frequency and amount of faeces as well as faecal water and lactic acid content. No other adverse effects were noted (Pieters et al., 1971). Comments The feeding studies with rats show that the modified starch is well utilized. The available evidence for the group of modified starches considered suggests that caecal enlargement without associated histopathological changes is without toxicological significance. The short-term study shows no other significant effects related to treatment, the observed growth depression being the obvious result of the high dietary level used. A reproduction study in rats showed no significant compound-related effects. A long-term feeding study in rats showed no compound-related effect, apart from decreased weight gain, caecal enlargement, and an increased incidence of renal epithelial hyperplasia in female rats. Data derived from special studies with a group of modified starches suggest that the latter effect is due to an imbalance in dietary Ca/F and Mg. EVALUATION Estimate of acceptable daily intake for man Not specified.* * The statement "ADI not specified" means that, on the basis of the available data (toxicological, biochemical, and other), the total daily intake of the substance, arising from its use or uses at the levels necessary to achieve the desired effect and from its acceptable background in food, does not, in the opinion of the Committee, represent a hazard to health. For this reason, and for the reasons stated in individual evaluations, the establishment of an acceptable daily intake (ADI) in mg/kg bw is not deemed necessary. REFERENCES De Groot, A. P. & Spanjers, M. Th. (1970) Unpublished report No. R 3096 by Centraal Instituut voor Voedingsonderzoek, Zeist, Holland De Groot, A. P., Til, H. P., Feron, V. J., Van der Meullen, H. C. D. & Willems, M. I. (1974) Two-year feeding and multigeneration studies in rats on five chemically modified starches, Fd. Cosmet. Toxicol., 12, 651-663 Hodgkinson, A., Robertson, W. G., Fourman, J. & Davis, D. (1981) A comparison of the effects on mineral metabolism of diets containing waxy maize starch, either of two chemically-modified waxy maize starches, or lactose. Unpublished report from the General Infirmary, and from the Medical School, University of Leeds (1981). Submitted by the US Food and Drug Administration to the World Health Organization, 1982 Leegwater, D. C. (1971) Unpublished report No. F 3431 by Centraal Instituut voor Voedingsonderzoek, Zeist, Holland Newberne, P. M. & Buttolph, M. L. (1977) A preliminary report of a thirty-day study in hamsters fed modified starches. Unpublished report from Massachusetts Institute of Technology (1977), submitted by the US Food and Drug Administration to the World Health Organization, 1982 Pieters, J. J. L., van Staveren, W. A. & Brinkhuis, B. G. A. M. (1971) Unpublished report No. R 3433 by Central Instituut voor Voedingsonderzoek, Zeist, Holland Roe, F. J. C. (1979) Mineral deposition in the renal pelvis of rats: A brief review. Unpublished report submitted to the World Health Organization Shillam, K. W. G. et al. (1971) Unpublished report No. 3978/71/136 by Huntingdon Research Centre Shillam, K. M. G. et al. (1973) Unpublished report No. CRN5/73254 by Huntingdon Research Centre Til, H. P., Feron, V. J., Spanjers, M. Th. & de Groot, A. P. (1971a) Chronic (two-year) feeding study in rats with two chemically modified starches (acetylated distarch phosphate and acetylated diamylopectin phosphate). Unpublished report from report No. R 3351. Centraal Instituut voor Voedingsonderzoek, Zeist, Holland. Submitted to WHO de Groot, A. O., Til, H. P., Feron, V. J., Dreef-van der Meulen, H. C. & Willems, M. I. (1971b) Two-year feeding and multigeneration studies in rats on five chemically modified starches. Unpublished report from Centraal Instituut voor Voedingsonderzoek, Zeist, Holland. Submitted to WHO
See Also: Toxicological Abbreviations Acetylated distarch phosphate (FAO Nutrition Meetings Report Series 46a) Acetylated distarch phosphate (WHO Food Additives Series 1) Acetylated distarch phosphate (WHO Food Additives Series 5) ACETYLATED DISTARCH PHOSPHATE (JECFA Evaluation)