This year, with nearly one in five U.S. adult consumers purchasing or consuming products tagged as gluten-free, sales of gluten-free foods and beverages are expected to reach $4.2 billion, reports Packaged Facts. The report indicates that the gluten-free category is seeing saw a compound annual growth rate of 28% over the past four-year period. While Packaged Facts expects growth to moderate, it views the segment reaching $6.6 billion in sales by 2017.