By Kathleen Doheny
WebMD Health News
Reviewed by Brunilda Nazario, MD
Sept. 16, 2016 -- Not that many years ago, the letters "GF" on a restaurant menu would likely have puzzled many people. No longer.
These days, a gluten-free lifestyle has become one of the most popular diet trends in the U.S. One in five people now reduce or eliminate gluten, a protein found in wheat, barley or rye, in their diet, according to a 2015 Gallup poll.
Avoiding gluten is crucial for people with celiac disease. That's because in them, gluten damages the small intestine and nutrients can't be absorbed. Its symptoms include diarrhea, constipation, bloating, and pain.
But only about 1% of the population has celiac disease, and that number hasn't changed in recent years, says Hyun-seok Kim, MD, a doctor at Rutgers New Jersey Medical School in Newark. In a study released earlier this month, he looked at a national survey taken from 2009 to 2014. Although celiac disease numbers remained stable during that time, the number of people following a gluten-free diet tripled, from 0.5% of the population to nearly 2%.
The study's researchers say that some who follow a gluten-free diet without a diagnosis of celiac disease may have non-celiac gluten sensitivity. People with non-celiac gluten sensitivity have similar symptoms but don't have celiac disease. People with a wheat allergy may also follow the diet to prevent an allergic reaction.
But do others need to go gluten-free?
Who Is Going Gluten-Free, and Why?
Nearly 100 million Americans say they ate gluten-free products in 2015, says William F. Balistreri, MD, a doctor at Cincinnati Children's Hospital Medical Center. Americans spent an estimated $4 billion on gluten-free products in 2015, he says.
Kim's research has found that women are more likely than men to avoid gluten, and the diet is more popular among 20- to 39-year-olds. It's also popular among world-class athletes. In another survey, 41% of 910 world-class athletes and Olympic medalists said they followed a gluten-free diet at least half the time, and most had self-diagnosed their gluten sensitivity. Among the many stars reportedly going gluten-free are Gwyneth Paltrow, Russell Crowe, and Kim Kardashian.
"It's a trendy diet," says Peter H.R. Green, MD, director of the Celiac Disease Center at Columbia University, who wrote a book on gluten. "People want quick fixes, and diets are frequently used as a quick fix for issues.''
Many health care professionals such as dietitians and psychiatrists promote the diet to people without diagnosed celiac disease, Green says. He says that an executive, who did not have celiac disease, told him his life coach recommended going gluten-free. He suspects that the association with celiac disease gives the gluten-free diet a medical legitimacy, so health care professionals may feel it's responsible to recommend it.
Who Really Needs Gluten-Free and Does It Help?
If you have celiac disease, a gluten-free diet can provide relief from bloating and intestinal problems, Kim says. Although people who self-diagnose their gluten sensitivity report the same relief from symptoms, Kim says more research is needed. In one study, Balistreri notes, people with diarrhea-predominant irritable bowel syndrome (IBS) reported a gluten-free diet helped their symptoms, although more research is needed.
People have also reported that they lost weight after avoiding gluten, according to a commentary accompanying Kim's study. But the Celiac Disease Foundation says gluten-free diets may actually result in weight gain. In people with celiac disease, more nutrients are absorbed into the body as the intestines heal on a gluten-free diet, and gluten-free foods may also be higher in sugar and fat.
But Alessio Fasano, MD, director of the Center for Celiac Research and Treatment at Massachusetts General Hospital, says, ''Everybody affected by a gluten-related disorder, including people with celiac disease, wheat allergy, and non-celiac gluten sensitivity, should embrace a gluten-free diet.''
Although not all health care professionals agree, Fasano says that gluten sensitivity is definitely real: "The debate is, what it is and how many are affected by it."
Some experts say that the sensitivity to the gluten in wheat might not be the whole story. Wheat contains both gluten and poorly absorbed carbohydrates that can make you gassy. Limiting these carbohydrates has helped those with irritable bowel syndrome. This involves cutting out wheat, rye, lactose, fructose, apples, and other gassy fruits. Other research has also found that those with self-reported non-celiac gluten sensitivity improved on a gluten-free diet but improved even more when these carbohydrates were cut out, Balistreri says.
People who cut out gluten may also simply be eating healthier, others suggest. Many highly-processed foods contain gluten, and eliminating them may help people feel better.
Gluten-Free: The Downsides
While the gluten-free diet ''is lifesaving for those with celiac," Green says, for those without medical indications, ''we don't think a gluten-free diet is a very healthy diet. ... It's low in fiber and often enriched in fat and calories."
It also puts people at risk of nutritional deficiencies, Green says. "Wheat flour is fortified. They add folic acid, [other] B vitamins, and iron. Rice flour, a mainstay of gluten-free foods, is not. We have seen people with vitamin B deficiency." B vitamins help convert food into fuel, help repair cells, and have other important roles. Gluten-free diets are not always easy to follow, Green says. The products are typically more expensive than products that contain gluten.
Also, parents should not place children on a gluten-free diet without a medical reason, Fasano says.
"If the kid does not have celiac disease or allergy [to wheat], there is no reason to go on a gluten-free diet," he says. People who go on a gluten-free diet without a medical need often think they are choosing a healthy lifestyle, but they may be harming their health, Green says.
In an op-ed piece he co-wrote for the Los Angeles Times, he writes: "What gluten-free faddists don't seem to realize is that in excluding gluten, they're also excluding a host of nutrients that keep them out of the doctor's office, not in it."
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SOURCES: JAMA Internal Medicine, published online Sept. 6, 2016.Alessio Fasano, MD, director, Center for Celiac Research and Treatment, Massachusetts General Hospital. Hyun-seok Kim, MD, internal medicine resident, Rutgers New Jersey Medical School, Newark. Peter H.R. Green, MD, director, Celiac Disease Center, Columbia University, New York. William Balistreri, MD, gastroenterologist, Cincinnati Children's Hospital. Medscape: "Should We All Go Gluten-Free?" Feb. 4, 2016. Celiac Disease Foundation. Beyond Celiac.
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