Study Shows Gluten-Free Diets May Not Be the Health Boost You Think

If you’re filling your shopping cart with gluten-free breads, cereals, and other foods to improve your health, you might be better off choosing gluten-containing alternatives instead.

That’s the conclusion of a study published in December in the journal Plant Foods for Human Nutrition, which found that gluten-free products were, on average, higher in sugar and calories and contained less protein, dietary fibers, and some essential nutrients.

Gluten, a storage protein in wheat grains, is found in wheat flour-based foods. People with celiac disease, wheat allergies, or gluten sensitivities need to stay away from gluten because it can cause gastrointestinal problems and other symptoms when consumed. Celiac disease affects an estimated 1% of Americans, and it’s believed that up to 6% of the population has a gluten sensitivity.

Yet, one study found that about 22% of people without a diagnosed gluten sensitivity reported following or trying a gluten-free diet due to beliefs, often from unreliable sources, that the diet is healthier and more nutritious. Gluten-free products are a multi-billion-dollar industry.

“Many perceived benefits of gluten-free products, such as weight control, diabetes management, improved mental clarity, and enhanced bone health, are often reported in popular media, leading people to believe that avoiding gluten improves overall health,” Sachin Rustgi, PhD, study co-author and an associate professor of molecular breeding in Clemson University’s Department of Plant and Environmental Sciences, told Health. “However, these claims are not substantiated by medical research.”

Previous studies have found similar downsides to gluten-free foods, but they took place outside the U.S., Rustgi said.

To understand the nutritional profiles of gluten-free foods specifically found in the U.S., Rustgi and his colleagues decided to compare gluten-free products and their gluten-containing counterparts sold by the same manufacturer.

They settled on 39 products, including baked goods, snacks, ready meals, and breakfast items, and compared information about calories, sugar, dietary fiber, protein content, and price found on manufacturer and supermarket websites. 

Gluten-free products differed from the alternatives in some key ways. For one, they contained approximately 5% more sugar than their gluten-containing counterparts, with bakery products having the highest average sugar content.

The average calorie content of gluten-free items was also higher, at 377.88 kilocalories per 100 grams, compared to 352.02 kilocalories per 100 grams for regular products.

Foods free of gluten also had less protein, ranging from 0 to 32.5 grams per product compared to 1.24 to 76.67 grams for gluten-containing products. The protein content of some popular gluten-free items like tortilla wraps, pancake and waffle mix, seeded bread, and noodles was generally less than half of that found in gluten-containing equivalents.

Overall, the results weren’t surprising, the authors noted. Gluten-free products frequently replace traditional wheat flours with ingredients like corn starch, corn flour, and rice flour, which are naturally higher in carbohydrates and lower in protein.

The authors said that, for the sake of people who can’t eat gluten, they hope the findings spark changes to the way these products are manufactured.

However, there was one bright spot for gluten-free foods: They averaged about 22% higher in dietary fiber content than comparable gluten-containing products. That’s likely because gluten-free products often have added ingredients like inulin or amaranth that increase fiber content, Halle Saperstein, RD, a clinical dietitian at the Henry Ford Health System, told Health.

Of course, people with celiac disease, wheat allergies, or gluten sensitivities don’t have a choice as to whether to follow a gluten-free diet. But for everyone else, the findings suggest there are real reasons not to avoid gluten if you don’t have to.

“Your overall diet may be lacking in key components to a healthy diet, which may lead to nutritional deficiencies, gastrointestinal complications, and even weight gain,” said Saperstein. “Following a gluten-free diet, if not medically advised, can also lead to an alteration in our gut microbiomes,” leading to an overgrowth of harmful bacteria.

However, Shonali Soans, RD, a registered dietitian with the Integrative Health and Wellbeing program at Weill Cornell Medicine and New York-Presbyterian, told Health that whether a product is good for you or not goes beyond its gluten status.

“How healthy or unhealthy a product is depends on the ingredients and processing of the product, whether it’s gluten-containing or gluten-free,” she said.

Soans recommends following a varied diet based on whole foods rich in nutrients rather than packaged food to promote gut microbiome and overall health. If you opt for packaged foods, read product labels and look for whole-food ingredients without additives, refined sugars, or gums.

Even if you choose to nix gluten, Soans suggests not giving up healthy whole grains, which promote cardiovascular health and help regulate the digestive system.

“There are many naturally gluten-free grains out there like buckwheat, amaranth, quinoa, teff, sorghum, and so on that I think everyone could benefit from including in their diets in an effort to add more variety in, whether they are gluten intolerant or not,” said Soans.