Vegan Red: A Safer Alternative to Synthetic Food Dyes?

Abstract

Food colourants are widely used additives classified as either synthetic or natural. In recent years, consumers have increasingly favoured natural options, considering them safer and potentially beneficial due to their nutritional properties. This study examined the effects of a natural food colourant, commercially known as Vegan Red (RVEG), on zebrafish embryonic development. Its impact was compared with cochineal red E120, of animal origin, and the synthetic dye E124, which are associated with hyperactivity in children and allergies. Shield stage embryos were exposed for 72 h and then examined using a multidisciplinary approach to assess the effects on conventional toxicity endpoints, such as survival, hatching rate, heart rate, genotoxicity, and behavioural interferences, including the impact on muscle ultrastructure. The results demonstrated that RVEG, as well as E120, do not affect hatching, heart rate, and motility parameters. However, RVEG moderately alters skeletal muscle organisation and, more relevant, the expression of the gfap, chchd2, and notch1a genes. Based on standard toxicity parameters, the findings indicated that RVEG is less toxic than E124 and E120, but that the alterations induced in gene expression and muscle anatomy raise safety concerns.

Keywords: E120; E124; behaviour; gene expression; muscle ultrastructure; toxicity; vegan red; zebrafish embryos.

Figure 1

Effects of red dyes on hatching rate at 24, 48, and 72 h of exposure (a) and heart rate at 72 h of exposure (b). Significant differences were determined using one-way ANOVA followed by Tukey’s test (* p < 0.05).

Figure 2

Effects of red dyes on the embryos’ spontaneous movements while in the chorion. No significant differences were noticed (ns = not significant; one-way ANOVA followed by Tukey’s test).

Figure 3

Motility parameter of Danio rerio larvae, control or exposed to vegan red (RVEG), E120, or E124 for 72 h. (A) Velocity test (cm/s). (B) Acceleration test (cm/s²). (C) Distance moved (cm). (D) Steps (n). One-way ANOVA followed by Tukey’s test (* p < 0.05; ** p < 0.01; *** p < 0.001).

Figure 4

Skeletal muscle organisation in Danio rerio larvae, control or exposed to vegan red (RVEG), E120, or E124 for 72 h. (A–C) In control groups, dense myosepta (thin arrows) separate myomeres (m) containing regularly organised fibrils (*). Notice scarce interfibre connectives (thick arrows). (D–F) RVEG group displayed poorly stained myosepta (thin arrows), regular banding (*), and scarce interfibre connectives (thick arrows). In E120 (G–I) and E124 (J–L) groups, dispersed and pale myosepta (thin arrows), thick connectives separate single fibres (thick arrows), and regular banding (*) are visible. Myomers (m), neural tube (n), tail vessel (v). Semi-thin sections stained with toluidine blue. Magnification: 20×; 40×; 100×.

Figure 5

Ultrastructure of skeletal muscle in Danio rerio larvae, control or exposed to vegan red (RVEG), E120, or E124 for 72 h. (A–D) Regularly organised myofibrils with evident banding and Z-bands (z) in register are visible in the control group. Mitochondria (m) with tubular cristae and sarcoplasmic reticulum (arrow). (E–P) In dye-treated larvae, irregularly disposed myofibrils (*) with Z-bands (z) that are not always in register (double arrows) are visible. Dilated mitochondrial (m) cristae (empty arrows) and increased sarcoplasm among myofibrils (arrows). Significant increase in collagen content (c). Nuclei (n).

Figure 6

Effects of red food dyes on gfap, chchd2, and notch1a expression. Fold changes were calculated as: fold change = 2^−ΔΔCt. Blue lines indicated the fold change thresholds of 2 and 0.5, respectively. Values above 2 and below 0.5 were considered significant compared with the control. One-way ANOVA followed by Tukey’s test (* p < 0.05; *** p < 0.001; **** p < 0.0001).