( .” McGraw and Ardia describe their...)ASU research shows connection between testosterone, dietary antioxidants and bird coloration

McGraw and Ardia describe their findings in “Do carotenoids buffer testosterone-induced immunosupression" An experimental test in a colorful songbird,” in the current issue (June 6, 2007) of Biology Letters, a journal of the Royal Society, London.

The researchers experimentally examined the relationship between testosterone, carotenoids and immune state in 35 male and female zebra finches. They surprisingly found that when they administered testosterone implants to zebra finches that it acted as a stimulant to the immune system. They went on to show that carotenoids acquired from food and circulating through the blood were changing in ways that were linked to testosterone levels. Birds who were given additional testosterone depleted their carotenoid levels and became healthier, as if they were combating testosterone directly with antioxidants.

“These findings show that there are nutrient specific mechanisms by which animals can avoid the immune costs of testosterone elevation and still keep their attractive and bright colors,” McGraw said. Most previous studies of this sort have focused on physiological or even genetic links between testosterone and health. He adds that it is worth considering the implications for human nutrition and health.

“If testosterone is having immunosuppressive effects in human men, perhaps they too could benefit from increased carotenoid intake, say, by eating more corn,” he said.

“This study certainly opens the door for future work on nutritional/antioxidant therapy for the hormonally immunocompromised,” McGraw added. “The interface between diet and health in animals is a fascinating one. But we need a much better understanding of their interactions, as with testosterone, at the molecular level.”
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Source:Arizona State University