FAO Nutrition Meetings Report Series No. 48A WHO/FOOD ADD/70.39 TOXICOLOGICAL EVALUATION OF SOME EXTRACTION SOLVENTS AND CERTAIN OTHER SUBSTANCES The content of this document is the result of the deliberations of the Joint FAO/WHO Expert Committee on Food Additives which met in Geneva, 24 June -2 July 19701 Food and Agriculture Organization of the United Nations World Health Organization 1 Fourteenth report of the Joint FAO/WHO Expert Committee on Food Additives, FAO Nutrition Meetings Report Series in press; Wld Hlth Org. techn. Rep. Ser., in press. TANNIN (FOOD GRADE) Tannic acid was considered at the Tenth Meeting of the Joint FAO/WHO Expert Committee on Food Additives but no ADI could be established because of insufficient data (FAO/WHO, 1967). Those data and additional ones which are summarized below have been reviewed in the light of the use of tannins in food processing as a flocculant. Biological data Biochemical aspects None available on food grade material. Acute toxicity Animal Route Material LD50 Reference mg/kg body weight rat intragastric Aleppo tannin 1550 Food and Drug Res. Lab. (1964) intragastric Tara tannin 3700 Food and Drug Res. Lab. (1964) intragastric Chinese tannin 2800 Food and Drug Res. Lab. (1965) intragastric Sicilian sumac 2650 Food and Drug Res. Lab. (1967) tannin intragastric Douglas fir 7500 Food and Drug Res Lab. (1967) tannin Aleppo tannin stimulated lachrymation and CNS depression. The tannins generally appeared to produce motor depression and diarrhoea. Short-term studies Rat Seven groups of 15 males and 15 females received daily either 0, 8, 80 or 800 mg/kg body weight of Aleppo tannin or tara tannin in their diet for 12 weeks. Body weight, food intake and food utilization showed no significant changes related to the substance. Liver and kidney weights were similar for tests and controls. Gross and histopathology showed only incidental abnormal findings unrelated to the test substances (Food and Drug Res. Lab., 1964). Similar studies at these same levels using Chinese tannin (Food and Drug Res. Lab., 1965), Sicilian sumac tannin (Food and Drug Res. Lab., 1967) and Douglas fir tannin (Food and Drug Res. Lab., 1967) produced comparable findings. Dog Five groups of 4 males and 4 females received daily 0.0, 0.25, 0.234, 0.125 or 0.117% Peruvian tara tannin in their diets for 2 years. Chewing gum containing the tannin at a level of 0.5% was the material actually incorporated into the diet, No ill effects were noted at any level of tannin fed as judged by behaviour, food consumption, haematology, organ function tests, organ weights and gross and microscopic pathology (Rosner-Hixon Lab., 1965). Long-term studies Rat Five groups of 50 males and 50 females received daily 0.0, 0.25, 0.234, 0.125, or 0.117% Peruvian tara tannin in their diets for 2 years. Chewing gum containing the tannin at a level of 0.5% was the material actually incorporated into the diet. No ill effects were noted at any level of tannin fed as judged by survival, growth, food consumption, haematology, organ weights and gross and microscopic pathology (Rosner-Rixon Lab., 1965). Three-generation studies, 2 litters per generation, were carried out in groups of 20 males and 20 females using Peruvian tara tannin at feeding levels of 0.0 and 0.234% and at 0.0, 0.117 and 0.058%. Chewing gum containing the tannin at a level of 0.5% was the material actually incorporated into the diet. Pups of the group fed at the 0.234% level were found to have significantly lower weights at weaning as compared to the controls. This effect was not seen at the lower feeding levels, nor were effects upon fertility, gestation, viability or lactation indices seen at any feeding level (Rosner-Hixon Lab., 1969). Comments Almost all the early studies on commercial tannin from a variety of sources have shown hepatotoxicity. Their relevance to the assessment of food grade tannin is small because the presence of commercial tannins is excluded by the specification for food grade material. Some tannins occurring in natural foodstuffs, such as tea and coffee, are not toxic. Short-term studies are available on food grade tannins of specified origin but only Peruvian tara has been tested in long-term studies. While 2-year feeding studies in both dog and rat produced no effects at levels up to 0.25%, reduced body-weights at weaning were found for rat pups in a multigeneration study at a feeding level of 0.234%. Evaluation Level causing no toxicological effects in rats 1170 ppm (0.117%) in the diet, equivalent to approximately 60 mg/kg body-weight. Acceptable daily intake for man mg/kg body-weight Temporary 0-0.6* Temporary 0-0.3** Further work required by June 1973 Further information on specifications is required. Studies in a second species to demonstrate no increased toxicity beyond that shown for Peruvian tara for tannin. derived from Turkish Aleppo, Chinese tara and Sicilian sumac. REFERENCES Anon (1969) Lancet, ii, 34 FAO/WHO (1967) Wld Hlth Org. techn. Rep. Ser,373 Food and Drug Research Laboratories (1964, 1965, 1967) Unpublished reports submitted to WHO Rosner-Hixon Laboratories (1965) Unpublished report submitted to WHO Rosner-Hixon Laboratories (1969) Unpublished reports submitted to WHO * Derived from Peruvian tara. ** Turkish Aleppo, Chinese tara, Sicilian sumac.
See Also: Toxicological Abbreviations