Toxicological evaluation of some food
    additives including anticaking agents,
    antimicrobials, antioxidants, emulsifiers
    and thickening agents



    WHO FOOD ADDITIVES SERIES NO. 5







    The evaluations contained in this publication
    were prepared by the Joint FAO/WHO Expert
    Committee on Food Additives which met in Geneva,
    25 June - 4 July 19731

    World Health Organization
    Geneva
    1974

              

    1    Seventeenth Report of the Joint FAO/WHO Expert Committee on
    Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 539;
    FAO Nutrition Meetings Report Series, 1974, No. 53.

    GUAIAC RESIN

    Explanation

          This substance has been evaluated for acceptable daily intake by
    the Joint FAO/WHO Expert Committee on Food Additives (see Annex 1,
    Ref. No. 6) in 1961.

          The previously published monograph has been revised and is
    reproduced in its entirety below.

    BIOLOGICAL DATA

    BIOCHEMICAL ASPECTS

          Very little, if any, guaiac resin is absorbed, much is passed out
    in the faeces, and the remainder is destroyed in the colon (Johnson et
    al., 1938).

    TOXICOLOGICAL STUDIES

    Acute toxicity
                                                                     

                                    LD50          Reference
    Animal           Route       (mg/kg bw)
                                                                     

    Rat              oral        > 5 000          Lehman et al., 1951

    Mouse            oral        > 2 000          Lehman et al., 1951

    Mouse            i.p.        > 2 000          Lehman et al., 1951

    Guinea-pig       oral          1 120          Lehman et al., 1951
                                                                     

          Six human subjects took a total of 10 doses 2 or 3 g at a time.
    The only untoward sequel of ingesting these large quantities was the
    passage of one or two loose stools in some instances (Johnson et al.,
    1958).

    Short-term studies

    Rat

          Four groups of 10 rats received resin diets containing 10% lard 
    with 0%, 0.05%, 0.5% and 5% guaiac resin (0%, 0.005%, 0.05% and 0.5% 
    of the total diet). None of them showed any effect on growth rate 
    over a period of 41 weeks (Johnson et al., 1958).

    Cat

          Eight full-grown cats received a daily dose of 500 or 1000 mg of
    guaiac resin for 34 to 117 weeks. Body weight, general behaviour,
    appearance, red and white blood cell counts, and haemoglobin remained
    normal. Two of the cats fed for 74 weeks showed no irritation of
    intestinal mucosa; upon histological examination the lungs, kidney,
    liver and spleen were found to be normal (Johnson et al., 1958).

    Dog

          Guaiac resin in doses of 500 or 1000 mg was administered to
    11 fully grown dogs daily for 62 to 103 weeks. Body weight, general
    behaviour, appearance, red and white blood cell counts, and
    haemoglobin remained normal. Histological sections from three dogs
    (fed 1000 mg guaiacum daily for 75 weeks) showed a normal intestinal
    mucosa in each case, with no suggestion of irritation or injury. The
    lungs, kidney, liver and spleen from these dogs were normal upon
    microscopic examination (Johnson et al., 1958).

    Long-term studies

    Rat

          Forty rats were divided into four groups and fed diets containing
    lard with 0%, 0.05%, 0.5% and 5% guaiac resin (0%, 0.005%, 0.05% and
    0.5% of the total diet) for a lifetime study. The second and third
    generation descendants (80 in number) of the original rats were
    maintained throughout their lifetime on the same diet as their
    parents. No differences were observed between the experimental groups
    and the controls in regard to body weight, growth rate, life-span,
    reproduction, or pathological examination (Johnson et al., 1958).

          Groups of 10 rats each were maintained on diets containing 0% and
    0.5% guaiac resin for a period of two years. No discernible difference
    was observed between the two groups as determined by growth rate,
    mortality, and pathological examination (Lehman et al., 1951).

    OBSERVATIONS IN MAN

          Eleven human subjects (four female and seven male) received 50 or
    100 mg of guaiac resin daily for periods of 18 to 104 weeks. Red and
    white blood cell counts, haemoglobin, kidney function, body weight,
    number and consistency of stools, and general physical condition were
    unchanged throughout the experimental period (Johnson et al., 1958).

    Comments:

          The results reported provide a basis for estimating an acceptable
    intake for man. These include studies in dogs, cats and human subjects
    as well as biochemical studies on the action of guaiacun on the gut
    and its fate in the organism.

    EVALUATION

    Level causing no toxicological effect

          Rat: 5000 ppm (0.5%) in the diet, equivalent to 250 mg/kg bw.

    Estimate of acceptable daily intake for man

          0-2.5 mg/kg bw.

    REFERENCES

    Johnson, V. et al. (1938) Food Res., 3, 555

    Lehman, A. J. et al. (1951) Advanc. Food Res., 3, 197

    See Also:
       Toxicological Abbreviations
       GUAIAC RESIN (JECFA Evaluation)