Fifty shades of food colours – Associations with cancer risk in a French cohort

Abstract Background Colour additives are frequently used in foods. A randomised controlled trial showed that some of them resulted in increased hyperactivity in children. Experimental studies suggested the activation of inflammation, oxidative stress, and genotoxicity. Since estimating dietary exposure to colour additives is challenging, no prospective epidemiological study had investigated their association with cancer risk so far. Methods This study included 102,485 French adults from the NutriNet-Santé cohort (78.8% female, 2009-2022). Exposure to food colours was estimated using repeated 24h dietary records linked to comprehensive, brand-specific food composition databases on additives. Associations with incident cancer risk were assessed using multivariable Cox models adjusted for common confounders. Results 3,511 incident cancer cases were diagnosed during the follow-up (including 1,026 breast, 431 prostate, and 279 colorectal cancers). Exposure to total food colour additives was associated with higher overall and breast cancer risks: HR higher vs non-exposure = 1.11 (1.02-1.22) and 1.25 (1.05-1.48), respectively. Positive associations with overall cancer were also observed with carotenoids food additives E160 (HR = 1.15 (1.05-1.25)) and curcumin E100 (HR = 1.10 (1.10-1.20)). Positive associations with breast cancer risk were observed with carotenoid additives (HR = 1.21 (1.04-1.42)) and carmine E120 (HR = 1.27 (1.08-1.49)). Plain caramel E150a was positively associated with colorectal cancer risk (HR = 1.52 (1.08-2.14)). Conclusions In this large cohort, we observed positive associations between the exposure to several types of food colour additives and overall, breast and colorectal cancer risks. Key messages • These findings provide pioneering epidemiological evidence regarding the link between food colours and cancer risk. • Should they be corroborated, these results could have significant public health implications, given the widespread presence of these cosmetic additives in ultra-processed foods.