Pictured Recipe: Spaghetti Squash with Roasted Tomatoes, Beans & Almond Pesto
Forgoing gluten has been touted by celebrities and professional athletes as a healthful way to lose weight, boost your mood, improve overall health and ramp up athletic performance. And the public has taken notice: surveys suggest that nearly one in three Americans want to reduce the gluten in their diets, with other research estimating that those who were on a gluten-free diet without medical necessity nearly tripled from 1.6 million people in 2010, to more than 5 million people in 2014.
But it turns out that this trend is founded on rocky ground. "There is no evidence that removing gluten from the diet is, in and of itself, a means to better health or weight loss," said Rachel Begun, M.S., R.D.N., nutrition advocate and special diets expert. Because gluten is in many foods we should limit—cookies, cakes and refined grains—the anecdotal success of the diet may instead be due to eating more nutrient-rich foods, such as fruits and vegetables, beans, nuts, gluten-free whole grains, dairy and lean meats. "The ironic thing is that these foods—which we recommend to everyone for a healthy diet—are all naturally gluten-free," adds Begun.
Pictured Recipe: Sweet Potato Carbonara with Spinach & Mushrooms
Many misconceptions about gluten come from its involvement in three clinically diagnosed disorders that are estimated to affect up to 8 percent of the U.S. population: celiac disease, wheat allergy and nonceliac gluten sensitivity (NCGS). Gluten is a protein in wheat, rye and barley that isn't fully broken down during digestion. Some of these protein pieces cross the intestinal barrier, where our bodies normally mop them up without consequence. In celiac disease, these proteins cause an immune response and intestinal damage, with the only treatment being strict adherence to a gluten-free lifestyle. The symptoms of celiac can be GI-related (diarrhea, abdominal pain and weight loss) or non-GI (headaches, fatigue and joint pain), which can make it hard to self-diagnose. Similarly, wheat allergy is an immune-mediated disorder that causes a rapid onset of symptoms, including nausea, vomiting and respiratory trouble. These two disorders can be diagnosed using blood tests and confirmed, in the case of celiac disease, with a biopsy. NCGS, however, is a diagnosis of elimination. People with NCGS do not have celiac disease or inflammation, yet experience many of the same symptoms. Scientists do not yet know what causes NCGS (it could be another component of wheat besides gluten), but some patients do feel better after following a gluten-free diet, hence its name.
In these disorders, gluten needs to be avoided. But given the number of Americans choosing a gluten-free diet without first seeing a celiac-trained gastroenterologist, it seems that self-diagnoses are driving this trend. "Some people remove gluten and feel better, so they think that it doesn't matter if they are diagnosed with celiac disease or NCGS," says Maureen Leonard, M.D., clinical director of the Center for Celiac Research & Treatment at Massachusetts General Hospital. "But [a clinical diagnosis] has other implications—not only for family members, but for themselves." First-degree family members have a 5 to 20 percent higher risk of developing a gluten disorder compared to the general population. Plus, celiac patients themselves may have an increased risk of developing other autoimmune conditions, such as type 1 diabetes, thyroiditis or inflammatory bowel disorder.
Pictured Recipe: Spaghetti Squash Lasagna with Broccolini
While many naturally gluten-free foods make up a wholesome diet, whole grains, including wheat, are an important source of protein, fiber, vitamins and minerals (especially iron and zinc). Gluten-containing whole grains have also been shown to have beneficial effects on inflammation, blood sugar levels and antioxidant activity, and their consumption has been associated with a reduced risk of heart disease. In fact, a recent study published in the BMJ that compared gluten consumption to the risk of heart disease in a 26-year study of 100,000 men and women found that participants with the highest level of gluten consumption had a 15 percent lower risk of heart disease than those who ate the least gluten.
Furthermore, there's little evidence that gluten causes inflammation in those without celiac disease. Preliminary studies that did find an increase in inflammation are inconclusive, done in those with underlying gastrointestinal disorders and in whom celiac disease was often not clinically ruled out. Additionally, research in those with irritable bowel syndrome (IBS) is often confounded by the inclusion of foods that cause gas production and can make symptoms worse, called FODMAPs. FODMAPs is a collective term that includes foods high in fructose (like apples and pears), oligosaccharides (wheat and onions), galacto-oligosaccharides (legumes) and sugar polyols (sorbitol and mannitol). Because a gluten-free diet is also low in FODMAPs, this—not the absence of gluten—may be responsible for the improvement in symptoms. There's also not enough evidence that intestinal permeability—or leaky gut—is affected by eating gluten or not in those without celiac.
Despite the claims of professional athletes, there's no evidence that going gluten-free boosts endurance. A preliminary study in 13 healthy competitive Australian cyclists who were randomized to consume either a gluten-containing or gluten-free diet (with the food provided to them) found no change in performance after a week on either diet.
As far as going sans gluten for weight loss, the jury is still out. There have been no published trials to date examining the effect of the gluten-free diet and its impact on weight in those without celiac, and studies following newly diagnosed celiac patients have mixed results. One study published in the European Journal of Internal Medicine followed 698 newly diagnosed adults for one year after starting a gluten-free diet, finding that 69 percent of those who were underweight at diagnosis gained a healthy amount of weight, while 18 percent of those who began as overweight lost weight post-treatment.
Loading up on gluten-free products, which often contain the same amount of calories as their gluten-containing counterparts, may also not be beneficial for your waistline. "A diet consisting of too many gluten-free cakes, cookies and other foods containing mostly refined grains and empty starches is going to be high in calories while providing very little nutrition," says Begun, "which can lead to nutrition deficiencies and weight gain." Research in patients with celiac disease has found that the gluten-free diet is often low in fiber and several micronutrients (vitamins D and B12, folate, iron, zinc, magnesium and calcium), and may be higher in added sugars and saturated fat.
"Gluten-free" is far from an indicator of healthfulness. If you suspect gluten is an issue, seek a gastroenterologist who specializes in celiac disease and NCGS before making the switch. "This is so we can properly evaluate for celiac disease or nonceliac gluten sensitivity, counsel patients on how to embrace a gluten-free lifestyle and check in with them regularly to make sure they have a well-balanced diet and that there are no nutritional deficiencies," says Leonard.