Carlos Solis
Researchers studying orange and red melanin in bird feathers found that producing the pigment helps prevent cellular damage.
But what about humans? It turns out the pigment in red hair has a hidden strength we didn’t know about. This pigment, called pheomelanin, needs the amino acid cysteine to be made. Too much cysteine inside cells can cause oxidative damage, ScienceAlert reports.
According to a study by a team at the National Museum of Natural Sciences in Spain, people with genetic variants that promote pheomelanin production may have special cells capable of converting excess cysteine—obtained from food or the environment—into pigment.
Using zebra finches as a model, the scientists showed that pheomelanin can play a protective role in cellular health.
The researchers ran an experiment with male finches that couldn’t produce pheomelanin. After a month of feeding those birds extra cysteine, the males that lacked the pigment showed higher levels of oxidative damage than the birds that could make pheomelanin.
Female zebra finches do not produce pheomelanin, so blocking its production had no effect on them. Still, females given extra cysteine showed slightly higher oxidative damage than females that did not receive the supplement. The results suggest excess cysteine contributes to cellular damage, and producing pheomelanin may protect against that harm.
In humans, pheomelanin is concentrated in the lips, nipples, and genitals. In people with red hair, it’s also present in the hair and skin.
Researchers think the genetic variants that boost pheomelanin production probably help cells keep cysteine levels in balance by channeling surplus cysteine into pigment production.
“These results provide the first experimental evidence of the physiological role of pheomelanin, specifically its ability to prevent the toxic effects of excess cysteine, which helps us better understand the risk of developing melanoma and the evolution of animal coloration,” the authors of the study wrote in their report.
The findings were published in the journal PNAS Nexus.
Photo: Unsplash
