Allura Red AC and colon cancer mechanisms reviewed
What it found
In lab and animal studies, Allura Red AC damaged DNA, changed gut bacteria and caused low-grade colon inflammation.
The authors say it is not classified as a carcinogen but deserves more study.
What they found
Studies in people
Human exposure
Children aged 5 to 9 have the highest exposure to Allura Red AC, mainly from juice drinks, soft drinks, icings and ice cream cones. Lower-income, less-educated and African American individuals tend to have higher intake.
Hyperactivity in children
The 2007 Southampton study found that consuming Allura Red AC along with other synthetic dyes was associated with increased hyperactivity in children. This led the EU to require a warning label on foods containing these dyes.
Animal and lab studies
DNA damage in animals
Some mouse studies found DNA damage in colon cells after a single dose of 10 mg/kg or after 6 hours to 1 week at 7 mg/kg and 14 mg/kg. Other mouse studies found no DNA damage. All the negative studies used male mice, which may point to a sex difference.
Colon inflammation in mice
In mice, consuming Allura Red AC at 7 mg/kg/day for 10 months led to low-grade inflammation in the distal colon, higher levels of an inflammation marker called IL-6 in the blood, and more iNOS in the colon. Other mouse studies showed it worsened colitis, especially with early-life exposure.
Gut bacteria changes
Allura Red AC is broken down by gut bacteria through a process called azo reduction. This produces metabolites that can damage DNA and cause inflammation. Many common gut bacteria can do this, but E. coli is poor at it.
Other findings
Consumption increase
Since the 1970s, the amount of Allura Red AC certified by the FDA has risen about 25-fold. In 1977, average consumption was about 9 mg per day (0.13 mg/kg/day).
What the authors conclude
“Although there is no direct evidence that Allura Red AC alone causes cancer, it is important to note that experiments specifically designed to investigate Allura Red AC’s potential to accelerate the development of colorectal and other cancers have not yet been conducted.”
Also in their conclusions
- They say that increasing independent evidence shows Allura Red AC interacts with inflammation, DNA damage and the microbiome, all of which are involved in colorectal cancer.
- They call for government agencies like the FDA and EFSA to comprehensively evaluate food dyes such as Allura Red AC.
- They suggest that if future results support their hypotheses, the Delaney Clause could be used to prohibit further use of Allura Red in the USA.
How it was done
The authors note that synthetic food dye use rose in the 1970s and 1980s, followed by more metabolic diseases and early-onset colorectal cancer in the 1990s. They wanted to examine whether Allura Red AC might contribute to colon cancer.
The authors reviewed published studies on Allura Red AC, including animal experiments, lab tests and human surveys. They also described their own mouse study where Allura Red AC was given at 7 mg/kg/day for 10 months.
What it can’t tell you
- Most of the evidence comes from animal and lab studies, so it cannot show what happens in people.
- The human studies are surveys that can show links but not cause and effect.
- The authors note that no experiments have directly tested whether Allura Red AC alone causes cancer.
Who paid
- Funding
- Funded by NCI NIH HHS; NIH HHS (from the PubMed record).
- Authors work at
- University of South Carolina, United States
The paper
- Title
- Allura Red AC is a xenobiotic. Is it also a carcinogen?
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Hofseth LJ, Hebert JR, Murphy EA, et al (2024). Allura Red AC is a xenobiotic. Is it also a carcinogen?. Carcinogenesis. doi:10.1093/carcin/bgae057Free full textPubMed 39129647DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error