The next time you’re looking at the leaves that have changed color with the change of seasons, know that what you’re looking at is also part of the blood that flows through your veins.
The same naturally occurring pigments that cause leaves to change colors are also some of the same pigments that make human plasma yellow.
What are xanthophylls?
“Xanthophylls are a class of carotenoid pigments that function in leaves as accessory light-harvesting pigments (they absorb sunlight in the blue-green part of the spectrum and transfer energy to chlorophyll for photosynthesis),” explained Krishna Niyogi, Professor, Plant and Microbial Biology, at Berkley University of California via email.
Xanthophylls also function in photoprotection as antioxidants and quenchers of excess excited chlorophyll states (when there are excess light conditions), he said. “And, they are essential structural components for the assembly of light-harvesting antenna proteins that surround the photosystems in chloroplasts,” Niyogi added.
But what are the leaf pigments doing in human plasma?
“The xanthophylls lutein and zeaxanthin enter the human body through dietary intake of xanthophyll-rich foods such as leafy green vegetables and yellow corn,” Niyogi said, explaining how xanthophylls end up in plasma. He added that these pigments don’t just give plasma its color, but are likely beneficial. “They accumulate in the macula of the retina, where they probably function as screening pigments and antioxidants that contribute to eye health,” he said.