Your hair color may predict your future health, according to findings from a new study.
Researchers studying wild boars found that the animals with gray hair actually lived longer and led a healthier life.
However, the latest findings are more ominous for redheads. Researchers from Spain's Museo Nacional de Ciencias Naturales found that boars with more reddish hair tended to have more cell damage compared to gray boars.
The study, published in the July/August issue of the journal Physiological and Biochemical Zoology, revealed that red boars generally had higher levels of oxidative stress or damage that occurs as toxins from cell respiration accumulate over time.
Lead researcher Ismael Galván and his team explain that the connection between red fur and poor health could be because the process of producing reddish pigment uses up an essential antioxidant capable of fighting off foreign free radicals that causes oxidative stress of cell damage.
The latest findings could provide clues as to why red seems to be such a costly color in animals. Previous studies found that in humans, red hair and red pigments, or melanins, in skin are linked to higher rates of cancer.
"Given that all higher vertebrates, including humans, share the same types of melanins in skin, hair and plumage, these results increase our scant current knowledge on the physiological consequences of pigmentation," Galván said in a statement.
Galván and his team examined two types of melanin: eumelanins and pheomelanins.
Eumelanins produces dark colors like brown and black and pheomelanins produce brighter colors like red or rich chestnut hues.
Unlike eumelanin, pheomelanin eats up a chemical called glutathione, or GSH, to produce the color.
GSH is a powerful intracellular antioxidant, which means it can halt the harmful chemical reaction of oxidation that cause free radicals and cause cellular damage.
Researchers were curious to see whether producing red hair would use up the antioxidant and leave the body's cells more vulnerable to free radicals.
The scientists studied a population of wild boars in Doñana National Park in southwestern Spain by measuring the boars oxidative stress in the animals' muscles, and found that the more pheomelanin, which produces reddish pigments, a boar had in its fur, the more likely it was to have less GSH in the muscle cells and more oxidative stress.
"This suggests that certain colorations may have important consequences for wild boars," Galván said. "Pheomelanin responsible for chestnut colorations may make animals more susceptible to oxidative damage."
However, grey hair, a consequence from not having as much melanin, appeared to signal good health in wild boars.
"As with human hair, wild boars show hair graying all across their body fur," Galván said. "But we found that boars showing hair graying were actually those in prime condition and with the lowest levels of oxidative damage."
"Far from being a sign of age-related decline, hair graying seems to indicate good condition in wild boars," he said
However, researchers noted that previous studies have suggested that grey hair in other animals can be caused by cellular stress, and damage to melanocytes or the body's pigment-producing cells may explain why roots turn grey with age.