“Gluten-free substitute foods tend to have more fat, more sugar and more salt than gluten-containing counterparts, in general,” Dr. Lebwohl added. Gluten provides elasticity in dough and helps thicken various processed foods, so it can also be found in products like energy bars and deli meats. To compensate for the loss of texture, Dr. Lebwohl said, “gluten-free substitutes are often less healthy.”
Starting a gluten-free diet can also “interfere with the ability to detect celiac disease,” said Dr. Lebwohl, because the two abnormalities picked up by the primary testing tools for celiac disease — a blood test, which looks for certain antibodies, and a biopsy, which looks for intestinal damage — can normalize after just a few weeks of eliminating gluten.
“One of the frustrating scenarios for both doctor and patient is when a patient has a number of symptoms, starts a gluten-free diet, feels a lot better — maybe 90 percent better — but we still don’t know if they have celiac or not,” he said. “If someone is experiencing symptoms that might be related to celiac disease, that person should get tested first, before starting a gluten-free diet.”
While much has been written in books and online sources about the purported benefits of avoiding gluten, such as weight loss, cognitive well-being and overall wellness, these claims are not supported by evidence. Though some patients with irritable bowel syndrome, or I.B.S., may see symptoms improve after cutting out gluten-containing foods, research suggests it’s likely to be a result of something other than gluten.
Only about 1 percent of Americans have true celiac disease, a serious autoimmune disorder, and should follow a strict gluten-free diet. Another 6 percent or so have non-celiac gluten sensitivity, a milder condition tied to digestive problems and other symptoms that does not result in a positive test for celiac disease; observing whether symptoms improve after a trial elimination of gluten is the main method of diagnosis.
For everyone else, following a gluten-free diet is not advised. Still, a 2013 report by the NPD Group, a market research firm, found that as many as one in three Americans were trying to avoid gluten.
“The potential adverse health effects of gluten in those sensitive to it have reverberated in cyberspace, creating the impression that gluten is a bona fide toxin, harmful to all,” writes Dr. David L. Katz, director of the Yale-Griffin Prevention Research Center in his forthcoming book, “The Truth About Food.” “This is false; gluten is not ‘bad’ for those tolerant of it, any more than peanuts are ‘bad’ for people free of peanut allergy.”
“Avoiding whole grains because you’ve heard gluten is bad is like avoiding whole fruits because you’ve heard fructose is bad,” Dr. Katz said in an interview. A diet without gluten is most often associated with the inclusion of what he calls “ultra-processed, gluten-free junk foods” and the exclusion of highly nutritious whole grains. “Avoiding it systematically produces net harm both to diet and to health.”
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