It is well known that synthetic food colours especially some
azo dyes can provoke
hypersensitivity reactions such as
urticaria, angioneurotic oedema, and astma (Michaëlsson and Juhlin, 1973, Granholt and Thune, 1975). Natural food colours are scarcely investigated with respect to potential allergic properties.
Annatto extract, a commonly used food colour in edible
fats e.g. butter, has been tested in patients. Among 61 consecutive patients suffereing from chornic
urticaria and/or angioneurotic oedema 56 patients were orally provoked by
annatto extract during elimination diet. Challenge was performed with a dose equivalent to the amount used in 25 grammes of butter. Twentysix per cent of the patients reacted to this colour 4 hours (SD: 2,6) after intake. Similar challenges with synthetic
dyes showed the following results:
Tartrazine 11%,
Sunset Yellow FCF 17%, Food Red 17 16%, Amaranth 9%, Ponceau 4 R 15%,
Erythrosine 12% and Brillant Blue FCF 14%. The present study indicates that natural food colours may induce
hypersensitivity reactions as frequent as synthetic
dyes.