Going Gluten Free May Raise Your Type 2 Diabetes Risk: Study
If you don't have celiac disease or a gluten sensitivity, here's one reason you might not want to give up bread entirely.
Good news, bread lovers: Eating gluten may be one way to reduce your type 2 diabetes risk, according to preliminary research presented yesterday at an American Heart Association meeting in Portland, Oregon. The study authors say more research is needed to draw firm conclusions, but that their findings might be one reason to reconsider going gluten free.
For people with celiac disease or a diagnosed gluten sensitivity, of course, going gluten free isn't optional. But this type of diet has become more popular in recent years in people without those conditions, even though there’s not much evidence that cutting out gluten—a protein found in wheat, rye, and barley—does much for long-term health.
So Harvard researchers decided to investigate the link between gluten consumption and health outcomes, gathering data from three long-running studies involving nearly 200,000 people total. People in these studies filled out food-frequency questionnaires every two years, and also had their health monitored regularly.
Over roughly three decades, more than 15,000 participants were diagnosed with type 2 diabetes. The researchers found that most participants had gluten intakes below 12 grams a day, and that within this range, those on the higher end were less likely to develop diabetes.
One reason that low gluten intake might be associated with higher diabetes risk was that people who ate less gluten also tended to eat less fiber, the researchers noticed. Controlling for this measure explained part of the disparity, but not all of it. Those in the highest percentile for gluten consumption still had a 13% lower diabetes risk than those in the lowest, who ate less than 4 grams.
Study participants got most of their gluten from pastas, cereals, pizza, muffins, pretzels, and bread, and averaged between 6 and 7 grams a day, overall.
The researchers note that because the study was observational and participants self-reported their food intake, they are unable to show that low-gluten diets directly increase the risk of diabetes. And they point out that they didn’t look at gluten-free diets, largely because the study started in the 1980s before these diets were widely adopted.
But the research does add to a growing body of evidence that avoiding gluten may not be the best choice for everyone. Foods marketed specifically as gluten-free and made with alternative ingredients can be lower in fiber and other important nutrients, says lead author Geng Zong, PhD, a research fellow in the department of Nutrition at Harvard University's T.H. Chan School of Public.
“Our research shows that maybe gluten free is not be so beneficial to your health, at least in terms of diabetes risk,” says Zong. His team is also studying the long-term effects of gluten consumption on other health measures, including heart disease and weight gain.
Last month, a report from the American College of Cardiology’s Prevention of Cardiovascular Disease Council also recommended against the adoption of gluten-free diets for people without a medical necessity, noting that many of their health claims were unsubstantiated.
If you do follow a gluten-free diet, Health’s contributing nutrition editor Cynthia Sass, RD, says it’s important to eat plenty of whole, fresh, and minimally-processed foods—like fruits, vegetables, and gluten-free grains like quinoa and brown rice. Not only will this help you get more fiber, but it may reduce your exposure to arsenic and mercury, which may be hidden in many gluten-free processed foods.
All this being said, this study should not be taken as an excuse to overindulge in white bread, sugary breakfast cereals, and other refined carbs. Whole grains—including whole-wheat bread and pasta—are still the healthiest way to get your gluten fix.