Gf. Houben et Ah. Penninks, IMMUNOTOXICITY OF THE COLOR ADDITIVE CARAMEL-COLOR-III - A REVIEW ON COMPLICATED ISSUES IN THE SAFETY EVALUATION OF A FOOD ADDITIVE, Toxicology, 91(3), 1994, pp. 289-302
Food additives can be regarded as the safest constituents:of our daily
food. Nevertheless, complicated issues with respect to their safety e
valuation do also occur. In this review paper, some of these issues ar
e illustrated by the description and evaluation of the research on the
immunotoxicity of the food additive Caramel Colour III. Caramel Colou
r III is commonly used as a color additive in many products for human
consumption. Toxicity studies conducted in the seventies demonstrated
that administration of Caramel Colour III can cause a reduction in tot
al white blood cell counts in rats, due to reduced lymphocyte counts.
Studies reviewed in this paper demonstrated several other effects of C
aramel Colour III on the immune system of rodents, including disturbed
immune functions and changed resistance in infection models. In addit
ion, studies in rats demonstrated that most of the effects occur only
when the animals are fed a diet low in vitamin B6. The imidazole deriv
ative -acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole (THI) was fou
nd to be responsible for the immunotoxicity. Issues such as the mechan
ism of action of THI and the role of vitamin B6 are discussed. Finally
, the results of a human intervention study and the observed effect Le
vels of THI in rats are discussed in terms of safety of the use of Car
amel Colour III in our daily food supply.