Gluten is a protein found in wheat, barley, and rye. People who suffer from the autoimmune disorder Celiac disease are unable to consume any gluten in any form, usually even in extremely trace amounts. A gluten-free diet is the only treatment for Celiac disease, and requires extraordinary care to avoid "hidden" glutens common in processed food, often under the guise "natural flavorings".
Maintaining a gluten-free diet requires selecting grocery products with some care. Locally, Hiller's, Arbor Farms, Trader Joe's and Whole Foods each carry an assortment of gluten-free items and either label them as such or can provide a list of items in stock. Some specialists, such as Tasty Bakery, offer gluten-free baked goods.
Eating out is also a challenge because restaurant chefs, kitchen staff, and servers often fail to understand the nature of the requirement unless they have been specifically educated or trained on the topic. Silvio's Organic Pizza and the Stadium Market each offer gluten-free pizza, the Mainstreet Ventures restaurants each have gluten-free menus, as do Paesano's and Outback Steakhouse. The vegetarian restaurant Seva specializes in catering to people with food allergies, including gluten sensitivities - you can ask for a gluten-free menu, and for the Book Of Ingredients that lists the ingredients in every item on the menu. And almost everything at the Indian buffet restaurant Earthen Jar is gluten-free, including baked goods for dessert. Other restaurants, such as Eve, are comfortable addressing the issue for diners. Event caterers are, as a rule, less reliable about accommodating gluten-free diners. Angel Food Catering and Moveable Feast are two notable exceptions; each has staff trained to understand the issue.
The local support group is an e-mail list, where you can ask questions and connect with other local gluten-free people anytime. It's like a support group that is in session 24x7. Newcomers are welcome. The group keeps databases of reviews of local restaurants, grocery stores, and medical practitioners. You can find it here:: Gluten-Free Ann Arbor