Occurrence of azo food dyes and their effects on cellular inflammatory responses.

OBJECTIVES: The aim of this study was to examine the occurrence of five azo food dyes-tartrazine, sunset yellow, carmoisine, allura red, and ponceau 4 R-in the food supply chain of Singapore and their effects on the in vitro synthesis of leukotriene B4 (LTB4 ) and F2 -isoprostanes.

METHODS: Trained personnel recorded the names of foods and beverages sold in a local supermarket that contained at least one of the five azo dyes. The occurrence of the azo dyes in the local food supply was computed. The synthesis of LTB4 and F2 -isoprostanes from freshly isolated blood neutrophils were measured using gas chromatography-mass spectrometry.

RESULTS: Of the 1681 processed food items, 194 (11.54%) contained at least one of the five azo dyes. Tartrazine was most prevalent in food and beverage products sold in Singapore, followed by allura red, sunset yellow, ponceau 4 R, and carmoisine. The five azo dyes augmented the in vitro synthesis of LTB4 and F2 -isoprostanes from blood neutrophils. Tartrazine was significantly more potent in increasing LTB4 synthesis than the other dyes, which exhibited similar potencies. The five food dyes increased the formation of F2 -isoprostanes from blood neutrophils at all tested concentrations.

CONCLUSION: The high prevalence of azo dyes in the food supply of Singapore and their ability to elicit proinflammatory responses in vitro suggest a potential health risk to the local population.