[ti:Obesity and Brain Development: Is There a Link?] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:01.08]In the United States, about 25 million children are either overweight or obese. [00:09.56]A new study explored how being overweight or obese might affect brain development in children. [00:19.04]A report on the study appeared this month in JAMA Pediatrics, [00:24.56]a publication of the American Medical Association. [00:29.80]The writers suggested a link between body mass index, brain development [00:36.44]and "executive functions, such as working memory." [00:41.56]An editorial published with the report called the study an important addition [00:48.12]to growing evidence of a link between weight, brain structure and mental function. [00:56.32]It also warned against misinterpreting the findings. [01:01.96]The study involved 3,190 U.S. boys and girls, aged 9 and 10. [01:11.84]Researchers had height and weight measurements and MRI scans of their brains. [01:19.28]MRI is short for magnetic resonance imaging, [01:24.48]a method used to take pictures of organs and tissues within the body. [01:31.44]The children took computer-based tests of mental function, [01:36.48]including memory, language, reasoning and impulse control. [01:43.32]Nearly 1,000 of the kids — almost 1 in 3 — were overweight or obese, similar to levels nationwide. [01:54.52]Researchers found differences in the brain scan images of the heaviest children. [02:02.32]They observed slightly less volume -- the amount of space -- in the brain behind the forehead. [02:09.64]This area controls what are known as "executive function" tasks. [02:15.68]Such tasks include things like planning, controlling impulses [02:21.32]and dealing with two or more activities at the same time. [02:27.00]Compared with normal-weight children, the differences were small, [02:32.44]noted Scott Mackey, a neuroscientist at the University of Vermont. [02:39.04]The heaviest children also had slightly worse results on the computer-based tests of executive function. [02:49.16]But it is unknown whether any of the differences [02:53.20]had much of an effect on children's behavior or performance in school. [02:59.28]Those are the opinions of Mackey and Jennifer Laurent, a University of Vermont researcher. [03:06.76]Laurent was the lead author of the report on the study. [03:12.04]It is also unclear how the differences relate to weight. [03:17.60]Mackey said other factors not measured in the study, [03:22.08]including physical activity and good nutrition, are likely important. [03:29.08]Research in adults has linked obesity with low-level inflammation throughout the body. [03:37.36]The condition can damage blood vessels and may increase risks for heart disease and loss of mental ability. [03:46.60]Some studies have also found less brain volume in obese adults. [03:52.88]Researchers suspect that the decreased brain volume could be from inflammation. [04:00.92]The new study raises the possibility that inflammatory changes affecting weight, [04:07.48]brain structure and brain function might begin in childhood. [04:14.20]Eliana Perrin is a doctor and specialist of children's health at Duke University in North Carolina. [04:23.32]She co-wrote the editorial published in JAMA Pediatrics. [04:28.40]She says that people should be careful about how they interpret the study. [04:34.56]"We don't know which direction these relationships go nor do they suggest [04:40.92]that people with obesity are not as smart as people at a healthy weight," she said. [04:47.96]The latest research confirms results of earlier studies in children and adults, [04:54.80]but it leaves many questions unanswered, said Marci Gluck. [05:00.64]Gluck is with the U.S. National Institute of Diabetes and Digestive and Kidney Diseases. [05:08.12]She was not part of the research, and warned people against making a link [05:13.92]between executive function and intelligence. [05:17.72]Natasha Schvey is an obesity researcher with the Uniformed Services University of the Health Sciences. [05:27.96]She called the study impressive, but noted that many factors influence people's diets and obesity. [05:38.08]"We know from a lot of really good research that obesity is not as much [05:43.68]in an individual's control as we think it is. [05:48.04]People talk about willpower — that's a very small part of the equation," she said. [05:54.32]"There are much bigger contributors to our weight and a lot of it is genetic." [06:01.20]I'm John Russell. 更多听力请访问51VOA.COM