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Fecal mutagenicity arising from ingestion of fried ground beef in the human
Abstract:
Fried ground beef has been shown to contain mutagens, and the major mutagenic component has been identified as 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). Mutagens in feces of 3 adult volunteers were fractionated by treatment of the feces with blue cotton followed by chromatography on a carboxymethyl cellulose column. The chromatographic fraction, corresponding to MeIQx in terms of the position of elution, was examined for mutagenicity in S. typhimurium TA98 with metabolic activation. When meals containing no heated meat were eaten, this fraction of feces showed little or no mutagenicity. On eating fried ground beef, the feces excreted in the next two days showed greatly increased mutagenicity in this fraction. By eating no-meat meal subsequent to the meat meal, the mutagenicity resumed the original low level on the fourth day after the meat meal. The components in the mutagenic fraction were probably metabolites of the mutagens present in cooked meat, since analysis by high pressure liquid chromatography of the mutagenic fraction showed that the active components in the feces were different from the mutagens in cooked meat.
Insights
Consuming fried ground beef increases mutagens in feces, likely due to metabolites of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx). Fecal mutagenicity returns to baseline levels after a meat-free diet.
Area of Science:
- Food toxicology
- Gastrointestinal health
- Chemical carcinogenesis
Background:
- Fried meats contain mutagens, notably 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx).
- Human gut microbiota may metabolize dietary mutagens.
- Assessing the impact of cooked meat mutagens on human fecal mutagenicity is crucial.
Purpose of the Study:
- To investigate the presence and origin of mutagens in human feces after consuming fried ground beef.
- To determine if MeIQx or its metabolites contribute to fecal mutagenicity.
- To assess the reversibility of increased fecal mutagenicity.
Main Methods:
- Fecal samples from three volunteers were analyzed.
- Mutagens were isolated using blue cotton treatment and carboxymethyl cellulose chromatography.
- Mutagenicity was assessed using the Ames test with Salmonella typhimurium TA98 and metabolic activation.
- High-pressure liquid chromatography (HPLC) was used for component analysis.
Main Results:
- Feces from volunteers who consumed fried ground beef showed significantly increased mutagenicity in a MeIQx-corresponding fraction.
- This elevated mutagenicity was observed in feces excreted within two days after meat consumption.
- Mutagenicity returned to baseline levels by the fourth day after resuming a meat-free diet.
- HPLC analysis indicated that the active fecal components differed from the original mutagens in cooked meat, suggesting metabolism.
Conclusions:
- Fried ground beef consumption leads to increased mutagenicity in human feces, likely from metabolites of cooked meat mutagens like MeIQx.
- The human gut appears to metabolize these dietary mutagens.
- Fecal mutagenicity is transient and reversible with dietary changes.