The effect of tartrazine exposure on microbiota during early periods of life

Food additives are widely used in the food industry all over the world. Tartrazine, an azo dye used to give a lemon yellow color, is a frequently preferred food additive for coloring soft drinks, chips, instant pudding, honey, pickles, chewing gum, mustard, gelatin and baked goods. Tartrazine has been banned in some countries for causing allergies, asthma, skin rashes, hyperactivity and migraines, but is still used in Turkey and many other countries. It has been widely discussed in the current literature that many organic and inorganic elements taken into the gastrointestinal tract through food, including food additives, may have effects on the shaping of intestinal flora. It is known that tartrazine may be present in ready-to-eat foods that are commonly found in the diet of children. For these reasons, it has been hypothesized that tartrazine may be an active variable in shaping the intestinal flora in the peripubertal period and may play a role in the increase of bacterial strains whose association with diseases has been shown in previous studies. In order to test this hypothesis, 32 Wistar albino rats, 16 male and 16 female, 6 weeks old, were divided into two groups as tartrazine group and control group. Fecal samples were collected once a week for 12 weeks from rats fed ad libitum with standard pellet diet or 7.5 mg/kg body weight/day tartrazine supplemented water and standard pellet diet until adulthood and body weight changes were monitored weekly. Changes in the microbiota of the digestive tract after administration of tartrazine to rats were analyzed by next generation sequencing technique. According to the results, in male rats, tartrazine consumption significantly decreased the rate of body weight gain (%) compared to the control group (p<0.001). Changes in the gut microbiota induced by tartrazine intervention differed depending on sex. Accordingly, tartrazine induced a clinically significant increase in the Proteobacteria phylum in male rats compared to the control group, while the time-dependent increase in the same phylum in female rats lagged behind the control group. In male rats, tartrazine intervention decreased Firmicutes and Bacteroidetes phyla. In female rats Bacteroidetes increased while Firmicutes decreased in both control and intervention groups, although the end-of-experiment rate of the control group remained below that of the intervention group. In male rats, compared to baseline, the Firmicutes/Bacteroidetes ratio increased at the end of the experiment in both groups, with a more clinically significant change in the control group compared to the intervention group. In female rats however, tartrazine intervention decreased the Firmicutes/Bacteroidetes ratio. Finally, the Shannon index, which is used to assess bacterial diversity, decreased in tartrazine-treated male rats (p < 0.001) and increased in female rats (p < 0.001). These data indicate that tartrazine consumption, even at an acceptable daily limit, may have an effect on the composition of the gut microbiota. It is recommended that the possible effects of tartrazine-induced changes in microbiota on host health should be examined in further studies.