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Findings
Iguanas Let Their Guard Down
Iguanas on the Galapagos Islands may have taken the “just relax” mantra a little too far. With no predators besides hawks, which rarely attack them, the iguanas have failed to develop the appropriate stress response to danger. Researchers, including Tufts professor of biology Michael Romero, measured how close they were able to get to the iguanas—often as little as six feet—before the lizards moved away. After trailing the iguanas for 15 minutes, they looked at blood samples and found low levels of the stress hormone corticosterone. The iguanas’ inability to mount a flight response means that certain conservation practices, such as reintroducing tame animals into areas with aggressive predators, are unlikely to succeed.
A Blight on Sight
Low-quality carbs, like those found in potatoes, white bread, and white rice, may be linked to a common form of vision loss, according to research by Allen Taylor, chief of the Laboratory for Nutrition and Vision Research at the Jean Mayer USDA Human Nutrition Research Center on Aging. Taylor and his colleagues found that women who consumed diets with a relatively high glycemic index (that is, a tendency to cause rapid rises in blood glucose) were more likely to develop signs of macular degeneration than women who consumed diets with a low glycemic index. Given that the vessel-rich retina depends on blood glucose to function, researchers suspected that glucose metabolism might affect this part of the eye. The type of carbohydrates consumed appeared to matter more than the amount. The study was published in the American Journal of Clinical Nutrition.
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