The Study
Low cleavage activity of 15,15'dioxygenase to convert beta-carotene to retinal in cattle compared with goats, is associated with the yellow pigmentation of adipose tissue.
This study watched what happened when cows and goats ate different amounts of orange plant food. It found that cows ended up with yellower fat and had less of a certain enzyme than goats. But it didn’t prove the enzyme caused the yellow color — it just saw them happen together.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
Cows and goats eat the same yellow plant food, but cows keep more of the yellow pigment in their fat, making it look yellow.
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 511 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes — this explains why butter and beef fat can be yellow while goat milk and meat fat stay white, even when both animals eat the same diet.
- 2Cows had 0.19 to 0.45 units of enzyme activity in their gut; goats had 1.4 to 1.99 units.
- 3Cows kept more beta-carotene in fat, goats cleared it quickly.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
International journal for vitamin and nutrition research. Internationale Zeitschrift fur Vitamin- und Ernahrungsforschung. Journal international de vitaminologie et de nutrition
Year
2000
Authors
Ofelia Mora, J. Romano, E. González, F. Ruiz, Armando Shimada
Related Content
Claims (6)
When cattle eat grass, the beta-carotene in the grass builds up in their fat tissue and turns the fat yellow.
Cattle have less enzyme activity in their small intestine than goats, leading to more beta-carotene stored in their fat and yellower fat color, even when both animals eat the same amount of beta-carotene.
When cattle are fed more beta-carotene, their duodenal enzyme activity that converts beta-carotene to retinal increases from 0.19 to 0.45 nmol retinal per mg S-9 protein per hour, but this activity is consistently lower than in goats under the same feeding conditions.
When given the same dietary supplement, goats show beta-carotene in their blood only on day 10, while cattle maintain blood beta-carotene levels that match their intake throughout 120 days.
In cattle and goats, higher amounts of beta-carotene in the diet lead to higher levels of beta-carotene stored in the liver, with the highest storage occurring at a dose of 352 mg per kg of dry matter.
When cattle and goats eat the same amount of beta-carotene, cattle store more of it in their fat tissue than goats do.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.