If you want to brush up on your Gluten-free knowledge, here is a recent post on Harvard TH Chan’s Nutrition Source blog.
Of particular interest not only is the pace of growth, but that a top reason for choosing these foods (added emphasis):
“The gluten-free food industry has grown 136% from 2013 to 2015 with almost $12 billion in sales in 2015. Interestingly, studies show that people who do not have celiac disease are the biggest purchasers of gluten-free products.  Consumer surveys show that the top three reasons people select gluten-free foods are for “no reason,” because they are a “healthier option,” and for “digestive health.””