高中(學測,指考)模擬考◆英文題庫下載題庫

Does an organic strawberry contain more vitamin C than a conventional one? Maybe — or maybe not. Stanford University scientists have weighed in on the “maybe not” side of the debate after an extensive examination of four decades of research comparing organic and conventional foods. Fruits and vegetables labeled organic were, on average, no more nutritious than their conventional counterparts, which tend to be far less expensive. Another finding of the study was that organic produce, over all, contained higher levels of phosphorus than conventional produce. But because almost everyone gets adequate phosphorus from a wide variety of foods, they said, the higher levels in the organic produce are unlikely to confer any health benefit. All in all, they didn’t find any nutrition advantage in organic food. The study’s conclusions about pesticides, however, did seem likely to please organic food customers. Over all, the Stanford researchers concluded that 38 percent of conventional produce tested in the studies contained detectable residues, compared with 7 percent for the organic produce. They also noted a couple of studies that showed that children who ate organic produce had fewer pesticide traces in their urine. Similarly, organic meat contained considerably lower levels of antibiotic-resistant bacteria than conventionally raised animals did, though bacteria, antibiotic-resistant or otherwise, would be killed during cooking. People buy organic food for a variety of reasons — concerns about the effects of pesticides on young children, the environmental impact of large-scale conventional farming and the potential public health threat. But if the choice is based mainly on the hope that organic foods will provide more nutrients, “I would say there is no concrete evidence to choose one or the other,” Dr. Bravata, one of the scientists of the research, said.