Gluten troubles were once thought to be a problem primarily for those with celiac disease. But recent research indicates that gluten-related disorders extend to a far broader population, and affect far more than the digestive system. Duck through the doorway of Sweet Christine’s Bakery in Kennett Square, Pa., and you’re enveloped by the sights and smells of a classic neighborhood bakery. But what makes this bakery unusual is that everything from vanilla cupcakes to chewy chocolate-chip cookies to baguettes is gluten-free, baked with ingredients such as brown rice flour and tapioca, rather than wheat. As a result, the bakery has become a safe haven for people with both celiac disease and gluten intolerances.