FAO Nutrition Meetings Report Series No. 40A,B,C WHO/Food Add./67.29 TOXICOLOGICAL EVALUATION OF SOME ANTIMICROBIALS, ANTIOXIDANTS, EMULSIFIERS, STABILIZERS, FLOUR-TREATMENT AGENTS, ACIDS AND BASES The content of this document is the result of the deliberations of the Joint FAO/WHO Expert Committee on Food Additives which met at Rome, 13-20 December, 19651 Geneva, 11-18 October, 19662 1 Ninth Report of the Joint FAO/WHO Expert Committee on Food Additives, FAO Nutrition Meetings Report Series, 1966 No. 40; Wld Hlth Org. techn. Rep. Ser., 1966, 339 2 Tenth Report of the Joint FAO/WHO Expert Committee on Food Additives, FAO Nutrition Meetings Report Series, 1967, in press; Food and Agriculture Organization of the United Nations World Health Organization 1967 MANNITOL Synonyms D-Mannitol; Mannitol Chemical name 1,2,3,4,5,6-Hexanehexol Empirical formula C6H14O6 Structural formula H H OH OH ' ' ' ' HOCH2 - C - C - C - C - CH2OH ' ' ' ' OH OH H H Molecular weight 182.17 Definition Mannitol consists of D-mannitol and contains, after drying, not less than 98 per cent. and not more then the equivalent of 102 per cent. of C6H14O6. Description Mannitol is a white crystalline solid which is odourless and has a sweet taste. Uses Sweetening agent, humectant, sequestrant. Biological Data Biochemical aspects D-mannitol occurs widely in nature in a variety of plants, algae fungi and certain bacteria. L-Mannitol does not occur naturally. Traces of mannitol have been identified occasionally in human urine (Pitkänen Pitkänen, 1964). D-mannitol has a slow rate of absorption from the intestinal tract and exerts laxative properties. The laxative threshold for man was found to lie between 10 and 20 g of D-mannitol per single dose (Ellis & Krantz, 1941). D-mannitol fed to dogs was excreted in large quantities in the urine (Jaffe, 1883). When 14C-D-mannitol was given at a rate of 240 mg/rat orally to non-fasted rats, about 50 per cent. of the radioactivity was recovered in the expired 14CO2 (Wick et al., 1954). In similar experiments, also using 14C-D-mannitol at a rate of 500 mg/kg body-weight, fasted rats oxidized 40 per cent. of the dose to 14CO2, non-fasted rats 68 per cent,; 9.74 per cent. was stored in the carcass; 1.28 per cent. in the liver and 6.32 per cent. was excreted in the urine (Gongwer, 1963). Feeding D-mannitol to rats and dogs led to a small but significant increase of liver glycogen (Carr et al., 1933; Todd et al., 1939; Silberman & Lewis, 1933; Carr & Krantz, 1938). When 14C-D-mannitol was administered to rats by i.p.injection, 77-97 per cent. of the dose was excreted in the urine within 24 hours, and only 2-3 per cent. of the mannitol carbon was oxidized to 14CO2. Additional experiments using injection directly into the portal vein showed that mannitol could be oxidized by the liver only (Wick et al., 1954. I.v. administered D-mannitol was completely cleared by the kidneys of 2 dogs at rates identical to inulin and creatinine (Smith et al., 1940). Mannitol did not elevate the blood sugar level of dogs upon i.v. injection at a rate of 22.5 g/dog (Todd et al., 1939. In man, i.v. administration of D-mannitol is practiced for induction of diuresis in oliguria or for forced diuresis in poisoning cases or to measure the extracelluar fluid compartment. There is an extensive literature available on these aspects (Milne, 1965; Widdowson et al., 1964). Following, the. i.v. injection of 10 g D-mannitol into man, 81 per cent. of the dose was excreted unchanged in the urine and up to 80 g, produced no toxic effect (Smith et al., 1940). Administration of 25 g of D-mannitol on 3 subsequent days to man did not significantly influence either the blood sugar level or the respiratory quotient (Ellis & Krantz, 1941). When 100 g D-mannitol was fed to man, the maximum rise in blood sugar level was 10 mg per cent. (Field, 1919). Acute toxicity Animal Route LD50 References (mg/kg body-weight) Mouse oral 22 000 Gongwer, 1960 i.v. 16 800 Robb, 1964 i.p. 14 000-16 000 Deck et al., 1936 Rat oral 17 300 Gongwer, 1960 Mice diet with signs of central nervous system depression and gastrointestinal tract mucosal damage; rats died with predominantly gastrointestinal tract signs (Gongwer, 1960; Gongwer, 1961). Short-term studies Rat. Groups of 20 male rats were fed 35 per cent. sucrose plus 5 5 per cent. D-mannitol or 40 per cent. sucrose (control group) over a period of 3 months. The growth curves showed that D-mannitol was nutritionally inferior to sucrose (Ellis & Krantz, 1941). These results are in accordance with earlier findings, that mannitol is inferior to sucrose, as judged by weight gain of rats (Ariyama et al., 1929) Monkey. Three rhesus monkeys were each fed 3 g of D-mannitol daily,. for 3 months. Two animals were employed as controls. No toxic signs nor pathological changes were observed (Ellis & Krantz, 1941). Man. The i.v. injection of 10 g of D-mannitol daily over a period of 1 month produced no significant changes in non-protein nitrogen, or CO2- combining power of blood, red cell count or renal function (Ellis & Krantz, 1941). Long-term studies No data are available. Comments The poor absorption shown in the metabolic studies and a long clinical experience in man support the safety of D-mannitol. Evaluation The many studies that have bean carried out in man provide a basis for evaluation. Estimate of acceptable daily intake for man mg/kg body-weight Unconditional acceptance 0-50 Conditional acceptance 50-150 REFERENCES Ariyama, T. & Takahashi, K. (1929) J. agric. chem. Soc. Japan, 5, 674 Beck, F. F., Carr, C. J. & Krantz, J. C. jr (1936) Proc, Soc. exp. Biol. Med., 35, 98 Carr, C. J., Musser, R., Schmidt, J. E. & Krantz, J. C. jr (1933) J. biol. Chem., 102, 721 Carr, C. J. & Krantz, J. C. jr (1938) J. biol. Chem., 124, 221 Ellis, F. & Krantz, J. C. jr (1941) J, biol. Chem., 141, 147 Field, C. W. (1919) Proc. Soc. Exp. Biol. Med., 17, 29 Gongwer, L. E. (1960) Unpublished report submitted by Atlas Chemical Industries Ltd Gongweg L. E. (1961) Unpublished report submitted by Atlas Chemical Industries Ltd Gongwer, L. E. (1963) Unpublished report submitted by Atlas Chemical Industries Ltd Jaffe, M. (1883) Z. physiol. Chem., 7, 297 Milne, M. D. (1965) Ann. Rev. Pharmac., 5, 125 Pitkänen, E. & Pitkänen, A. (1964) Ann. med. exp. Fenn., 42, 113 Robb, B. J. (1964) Unpublished report submitted by Atlas Chemical Industries Ltd Silberman, A. K. & Lewls, H. B. (1933) Proc. Soc. exp. Biol. Med., 31, 253 Smith, W.W., Finkelstein, N. & Smith, H. W. (1940) J. biol. Chem., 135, 231 Todd, W. R., Myers, J. & West, E. S. (1939) J. biol. Chem., 127, 275 Wick, A. N., Morita, T. N. & Joseph, L. (1354) Proc. Soc. exp. Biol. Med.,85, 188 Widdowson, E. M. & Dickerson, J. W. T. (1964) In: Comar, L. C. & Brommer, F. "Mineral Metabolism" New York-London, Vol. IIA p. 13
See Also: Toxicological Abbreviations Mannitol (WHO Food Additives Series 21) MANNITOL (JECFA Evaluation)