Nearly one in five packaged foods and drinks on US grocery shelves contain synthetic dyes — substances linked to hyperactivity and other behavioral problems in children. Brightly colored products, especially those high in sugar like candies, cereals, and sports drinks, are the biggest culprits. Credit: Shutterstock Nearly one in five packaged foods and drinks in the United States contain synthetic food dyes, according to new research that analyzed 39,763 grocery store products. The study was