Water Bottle Warning

Think twice before drinking hot liquids from plastic bottles. New research from the University of Cincinnati shown that bottles made of polycarbonate plastic can release a certain endocrine-disrupting chemical up to 55 times faster when exposed to hot water. A synthetic chemical also found in baby bottles, bisphenol A (BPA) is known to mimic female hormones and alter endocrine function. Although there's limited research on BPA's human-health effects, a number of animal studies have concluded that the chemical may interfere with reproduction and hamper brain development.

Even when they're not filled with hot liquid, polycarbonate bottles can leak BPA. But occasionally drinking cold water from plastic isn't likely to drastically increase your exposure, says Kirby Donnelly, Ph.D., head of Texas A&M University's Environmental and Occupational Health department. Still, he notes, opting for glass or stainless-steel bottles is the best way to avoid BPA and other potentially harmful synthetic chemicals.