The Study
Differences in expression and activity of beta,beta'-carotene-15,15'- oxygenase in liver and duodenum of cattle with yellow or white fat.
This study looked at cows with yellow fat and white fat and found that the yellow-fat cows had a bit more of a certain enzyme in their liver. But it didn’t change anything—it just noticed a difference. So we can’t say the enzyme made the fat yellow, just that they tended to go together.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Cows that eat grass store yellow pigment (beta-carotene) in their fat. Their bodies try to break it down with an enzyme in the liver, but not enough gets broken down.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 510 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The enzyme activity difference is statistically significant but too small to prevent pigment buildup, so fat stays yellow.
- 2Cows with yellow fat had 0.004 higher enzyme activity in the liver than cows with white fat (p = 0.004), but their liver made the same amount of enzyme mRNA.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of animal physiology and animal nutrition
Year
2007
Authors
A. Morales, A. Gonzalez, A. Varela-Echavarría, A. Shimada, O. Mora
Related Content
Claims (4)
When cattle eat grass, the beta-carotene in the grass builds up in their fat tissue and turns the fat yellow.
Cattle with yellow fat have higher levels of a specific liver enzyme that processes pigments than cattle with white fat, even though the genetic instructions for making the enzyme are the same, suggesting that regulation after gene expression affects enzyme activity.
Cattle with yellow fat and cattle with white fat have the same levels of β,β'-carotene-15,15'-oxygenase mRNA in their liver and duodenum, meaning differences in enzyme activity are not caused by differences in gene transcription.
Cattle with yellow fat and cattle with white fat have the same level of enzyme activity in their duodenum that breaks down beta-carotene, meaning differences in fat color are not primarily caused by how the intestine processes this compound.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.