Enlarge By Damian Dovarganes, AP People shop at the Costco Wholesale store in Burbank, Calif. Costco said Oct. 28 it will start accepting food stamps nationwide after testing them in New York. KIDS ON FOOD STAMPS KIDS ON FOOD STAMPS FOOD STAMP ELIGIBILITY FOOD STAMP ELIGIBILITY Food stamp eligibility for a family of four: • Monthly gross income: $2,389 or less • Cash resources, such as a bank account: $2,000 Source: U.S. Department of Agriculture Half of American kids will live in households receiving food stamps before age 20, according to a study reported Monday in Archives of Pediatrics & Adolescent Medicine. Although one in five children rely on food stamps for years, many more live in families who turn to food stamps during a short-term crisis, says author Mark Rank of Washington University in St. Louis. He analyzed 30 years of data from the University of Michigan's Panel Study of Income Dynamics survey. RETAILERS: Costco to accept food stamps nationwide VIDEO: Healthy breakfast on $1 HEALTHY LUNCH: On just $2 "This is what children can expect over a period of time, not just during a recession," Rank says. "It shows that the period of childhood, rather than a period of safety and security, is really a time, for a lot of kids, of economic turmoil and risk." Rank says his study, the first of its kind, may underestimate how many families struggle with grocery bills. Only about 67% of people who are eligible for food stamps actually receive them, the Department of Agriculture says. Good nutrition in childhood is crucial, doctors say. Nutritional programs such as food stamps — officially known as the USDA's Supplemental Nutrition Assistance Program — improve children's health and help them do better in school, says James Weill of the advocacy group Food Research and Action Center, who wasn't involved in the new study. More than 35.8 million Americans used food stamps in July — nearly 6.8 million more than a year earlier, Weill's group says. About half of food stamp recipients are children, Rank says. "There is a large pool of people who are poor or who are living close to poverty at any given time," Weill says. "People don't like talking about it. They don't tell their neighbors, 'I was on food stamps 10 years ago.' " Robert Rector of the Heritage Foundation, a Washington think tank, says the study design and survey data are solid. But he says the findings are neither surprising nor troubling. "That's effectively like saying that at some point in a 20-year period, a parent would be unemployed for a month or so," Rector says. "There's no evidence that even consistent poverty in the U.S. produces a nutritional risk," he says, noting that rich and poor children tend to have about the same intake of protein, vitamins and minerals. Guidelines: You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. You share in the USA TODAY community, so please keep your comments smart and civil. Don't attack other readers personally, and keep your language decent. Use the "Report Abuse" button to make a difference. Read more