According to halakhah (Jewish law), bread needs to have been made from any of five grains (wheat, barley, oats, rye, and spelt) and a majority proportion of water to any other "liquid" (classified as oil, sugar, honey, and eggs). Yeast added to the mixture is not taken into consideration as shown with matzah during Pesach (Passover). Therefore if one encounters a "bread" product made with apple juice (rather than water), it is technically mezonot (a baked good) rather than motzi. [In frumspeak (lingo used by frum Jews, those who are ritually observant), foods are often categorized by the blessing one recites before eating it. Therefore, hamotzi is anything that is actual bread, and requires the ritual washing and full Birkat ha-Mazon (Grace after Meals). Mezonot is the last word of the blessing on any other flour-based product that is not bread, such as cookies, crackers, cake, and pasta.]
Called the "staff of life", bread is the basis of a meal. During Shabbat, Jews sit down to several meals, all containing challah, a "fancy" braided loaf. This can be problematic for the person who is gluten-sensitive. Solutions for some have included not eating the bread at all or eating a small bite (depending on the sensitivity level). No rabbi worth following would suggest that one with a food allergy should feel forced to eat bread, as pikuach nefesh (saving one's life) takes precedence over the observance of mitzvot (commandments).
There are several gluten-free "breads" on the market made from rice flour. The best-tasting one I have found is made by Food for Life (see picture at beginning of post). They make an entire line of whole grain (for the non-celiac) as well as gluten-free/wheat-free bread products. They are rice flour-based and are considered she-hakol (the "catch-all" blessing for food that is no longer in its original recognizable form). All their products are certified by the kaf-K as pareve. Food for Life is also sold at Trader Joe's and Whole Foods. Some have the custom of regarding this as "bread" and will treat it as motzi since it is "bread" to them. However, it is not motzi.
Since I am gluten-sensitive and not a celiac, I have started to bake loaves of oat bread for exclusive consumption on Shabbat (I'Y'H, I will post recipe and pictures soon) while eating the rice flour bread during the week. I like this custom I have taken for myself since it reminds me of the specialness that Chazal (Rabbis from the Talmudic era) placed upon bread in the first place. Historically, it was common for poor people to make "bread" from "inferior" flours by grinding lesser grains (as well as legumes and nuts). Wheat was more expensive and it therefore makes sense that it would have been reserved for "special occasions" such as Shabbat. Today, wheat flour is VERY available and eaten, sometimes to excess.
Please check for my post Pesach for the Gluten Sensitive where I will go into detail about handling Pesach.
[Note: I advocate a high consumption of whole grains in any eating plan rather than enriched. All whole grains have the fiber and vitamins that are stripped in the refining process, but added in a synthetic form as "enrichment". Non-gluten sensitive people should continue to select whole grains at least half the time over the white stuff. To illustrate my point to people, I have taken white flour and water, mixed it together and made paste. (This does not work with whole wheat flour.) In my case, as well as the millions of people worldwide who are gluten sensitive, eating wheat adds more problems than it is worth. It is recommended for gluten sensitive people to choose brown rice over white and other non-gluten grains as a part of a balanced varied diet.]