NTP study: Food coloring byproduct is toxic to rat reproduction
Scientists in the Division of the National Toxicology Program (NTP) at NIEHS have demonstrated that 4-methylimidazole (4-MI) can cause toxic effects to rat reproduction and development. 4-MI, a chemical that is a byproduct of caramel coloring manufacturing, is found in various products, such as carbonated beverages, pancake syrup, and coffee. Previous studies have documented its adverse effects in liver and lung tissue, and the International Agency for Research on Cancer, part of the World Health Organization, has classified 4-MI as a possible human carcinogen.
Researchers exposed multiple generations of male and female rats to different doses of 4-MI via their diet. Rats that received 4-MI displayed a reduction in mating, producing litters, and number of offspring per litter. Such findings were associated with three outcomes:
- Exposed male rats and their offspring displayed abnormal changes in the prostate and delayed sperm release.
- Exposed female rats experienced disturbances in giving birth.
- Both sexes showed delays in pubertal development after 4-MI exposure.
The lowest dose of 4-MI at which these adverse effects were observed was 750 parts per million, equivalent to a daily intake of 50-60 mg per kg of body weight. This study expands the knowledge of potential health risks associated with 4-MI. (DY)
Citation: Behl M, Willson CJ, Cunny H, Foster PMD, McIntyre B, Shackelford C, Shockley KR, McBride S, Turner K, Waidyanatha S, Blystone CR. 2020. Multigenerational reproductive assessment of 4-methylimidazole administered in the diet to Hsd:Sprague Dawley SD rats. Reprod Toxicol; doi: 10.1016/j.reprotox.2020.03.005 [Online 27 March 2020].