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Last summer, the FDA finally defined "gluten-free" foods as those containing no wheat, barley, or rye (unless the gluten protein has been removed) and having less than 20 parts per million of gluten. The new rules take effect in August 2014. But there's still a problem: While most people with celiac disease or gluten sensitivities can safely tolerate a scant amount of gluten, many can't . Foods labeled "gluten free" or "no gluten" might still make them sick.