The Study
Effect of Dietary Carotenoid on Egg Yolk Color and Singlet Oxygen Quenching Activity of Laying Hens
This study is like a carefully run science experiment with chickens. It shows that giving certain colorful plant extracts to hens really does change how red or yellow their egg yolks become, and makes the yolks better at fighting harmful molecules. But it only tells us about eggs from these specific hens, not about people eating the eggs.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Some chickens are fed special plant powders to make their egg yolks more orange. This study checked which chickens make the most colorful and healthy yolks when given these powders.
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 515 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The darker orange yolks have more antioxidants, which may be better for health, but the study doesn’t prove it changes nutrition for people eating the eggs.
- 2After 4 weeks, eggs from chickens fed paprika, marigold, or Paracoccus powder had yolk color scores from 9.7 to 14.4 (vs 7.2–7.3 normally).
- 3Silky Fowl chickens had more yellow-orange nutrients in their yolks than Rhode Island Reds.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of Poultry Science
Year
2022
Authors
S. Kojima, Sakura Koizumi, Yukari Kawami, Yuna Shigeta, Aya Osawa
Related Content
Claims (6)
Giving certain plant and bacterial supplements to two types of chickens—Rhode Island Reds and Silkies—makes their egg yolks richer in colorful nutrients called carotenoids after a month, and Silkies seem to absorb more of these nutrients than the other chickens.
Silky Fowl chickens put more eye-healthy nutrients into their egg yolks than Rhode Island Reds when they eat certain colorful plant supplements — it’s in their genes!
Giving hens certain natural supplements like paprika or marigold extract makes their egg yolks better at neutralizing harmful oxygen, and this works in two different types of chickens after a month.
Giving chickens certain natural color supplements like paprika or special bacteria powder makes their egg yolks much more yellow or orange — way more colorful than usual.
Silky Fowl chickens naturally have eggs with better antioxidant power than Rhode Island Red chickens, even without any special diet — and it gets even stronger when they eat carotenoids.
Farmers add paprika and marigold to chicken food to make egg yolks look more orange because people think those eggs are healthier—even if they're not.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.