INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY

    WORLD HEALTH ORGANIZATION



    TOXICOLOGICAL EVALUATION OF SOME
    FOOD COLOURS, ENZYMES, FLAVOUR
    ENHANCERS, THICKENING AGENTS, AND
    CERTAIN FOOD ADDITIVES



    WHO FOOD ADDITIVES SERIES 6







    The evaluations contained in this publication were prepared by the
    Joint FAO/WHO Expert Committee on Food Additives which met in Rome,
    4-13 June 19741


    World Health Organization     Geneva     1975






              

    1  Eighteenth Report of the Joint FAO/WHO Expert Committee on
    Food Additives, Wld Hlth Org. techn. Rep. Ser., 1974, No. 557.
    FAO Nutrition Meetings Report Series, 1974, No. 54.

    IRON OXIDES AND HYDRATED IRON OXIDES

    BIOLOGICAL DATA

    BIOCHEMICAL ASPECTS

         The vital biological role of iron is well established. Iron
    preparations have been used as the standard treatment of iron-
    deficiency anaemia in man and animals. Over 70% of the body's iron is
    normally present as haemoglobin, 3% as myoglobin and 16% as transport
    iron. Iron may be stored in two forms: ferritin - an iron-protein
    complex - and haemosiderin (Lancet, 1963; IARC, 1972).

    TOXICOLOGICAL STUDIES

    Acute toxicity
                                                                  

    Species        Route     LD50              Reference
                             (Iron oxide)
                                                                  

    Rat            p.o.      > 15 g/kg          )
                                                )
    Mouse          p.o.      > 15 g/kg          ) Steinhoff, 1972
                                                )
    Rat            i.p.      > 15 g/kg          )
                                                                  

    Short-term studies

         No specific studies on monoxides or hydroxides are available.

    Long-term studies

         There are many studies by the inhalational, intratracheal,
    subcutaneous and intramuscular route in relation to the potential 
    carcinogenic effect of iron ore dust and haematite dust. These are 
    not relevant to the evaluation of iron oxide and hydroxide pigments 
    as food colours. No specific long-term feeding studies of iron oxides
    and hydroxides are available.

    Comments:

         There has been no toxicological investigation of the various iron
    oxides and hydroxides used as colouring agents either in animals or in
    man by oral administration. In spite of the extensive knowledge of the
    physiological and pharmacological effects of other forms of iron, the

    data cannot be extrapolated specifically to these compounds. Each must
    be evaluated in its own context and consideration given to the problem
    of haemosiderosis.

    EVALUATION

         Acceptable daily intake not specified.*,**

    FURTHER WORK OR INFORMATION

    Required by June 1978

         Adequate information on the absorption and storage of iron
    following use of these pigments as food additives.

    REFERENCES

    Anonymous (1963) Lancet, 1, 428

    IARC (1972) Monographs on the Evaluation of Carcinogenic Risk of
         Chemicals to man, Vol. 1, 29

    Steinhoff, D. (1972) Personal Communication

              

    *    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 any acceptable
    daily intake (ADI) in mg per kg of body weight is not deemed
    necessary.

    **   Temporary.

    See Also:
       Toxicological Abbreviations