The Facts about Gluten-Free Eating
Gluten-free diets are popular, but it is unclear how helpful they may be for most people.
The gluten-free foods market has exploded in the past decade. It is important for people following or considering a gluten-free diet to know the facts.
Gluten Sensitivities: Gluten refers to a family of proteins found in wheat, barley, rye, and triticale. Gluten proteins give dough its elasticity. For the approximately one percent of the population with celiac disease (a genetically-based autoimmune reaction to gluten) following a gluten-free diet is essential to health.
Data suggest that approximately ten percent of people feel they have sensitivity to wheat, even though they do not have celiac disease. “There is a condition known as non-celiac gluten sensitivity (NCGS),” says John Leung, MD, an allergist, gastroenterologist, and director of the Center for Food Related Diseases at Tufts Medical Center. “Patients present with no evidence of celiac disease in blood tests or biopsies, but they report their gastrointestinal symptoms improve with avoidance of gluten.” However, a large review of studies surprisingly found that most people who follow a gluten-free diet for self-diagnosed NCGS do not actually develop any symptoms after eating gluten. “A recent study published in the journal Gastroenterology provides evidence that many people who think they have gluten sensitivity may actually be reacting to fructans, short-chain carbohydrates found in wheat, onions, and a number of other plant foods,” says Leung.
Around twenty percent of consumers who follow a gluten-free diet do so because they consider it a healthy lifestyle option, but there have been no major studies on the use of a gluten-free diet for general health benefits or for weight loss. “Gluten-free diets may potentially help people move toward a healthier dietary pattern because they prohibit refined wheat products and the added sugars found in many wheat-rich foods,” suggests Dariush Mozaffarian, MD, DrPH, dean of the Friedman School of Nutrition Science and Policy and Editor-in-Chief of Tufts Health & Nutrition Letter, “but few health benefits may occur if gluten-containing foods are simply replaced with white rice and other refined starches.”
The Gluten-Free Diet: For those with celiac disease, following a gluten-free diet involves more than just avoiding wheat, barley, rye, and triticale. “Breads, pastries, baked goods, cereals, and wheat pastas are common gluten-containing foods, but processed foods may contain gluten-containing additives like malts and unprocessed wheat starch,” says Nicola McKeown, PhD, a scientist at Tufts’ Jean Mayer USDA Human Nutrition Research Center on Aging, “so gluten may be hiding in foods like granola bars and salad dressings.” Minimally processed fruits, vegetables, beans, nuts, seeds, and animal proteins are naturally gluten-free, as are a number of grains such as buckwheat, corn, and rice. For processed foods, gluten-free labels can help identify safe choices, although many products are not marked, so learning what to look for on ingredient lists is important.
Some scientists are concerned that replacing gluten-containing foods with gluten-free refined starches may increase risk for nutrient inadequacy. “Processed gluten-free foods, such as gluten-free cookies or snack foods, are often made from unfortified or unenriched rice, tapioca, corn, or potato flours,” says McKeown. “This means they lack certain nutrients (like iron, folic acid, and other B vitamins) that are found in whole grains and typically added to commercial wheat flour. These types of processed gluten-free foods also may be of low nutritional quality, as they are often high in calories, sugar, and sodium, and low in fiber.” Since many processed gluten-free foods are made with rice flour, there is also some concern about over-exposure to arsenic-contaminated rice when following a gluten-free diet. Additionally, data from a recent study in the Journal of Human Nutrition and Dietetics suggest gluten-free processed foods may be more expensive than their gluten-containing counterparts. Replacing gluten-containing foods with naturally gluten-free whole grains (like brown rice, corn, buckwheat, and quinoa) instead of processed gluten-free products should improve the nutritional quality of a gluten-free diet.
While it is possible to construct a nutritious gluten-free diet, this diet should not be undertaken without expert nutritional guidance. Also, other illnesses can present with similar symptoms. “Patients often associate gastrointestinal symptoms with food, however not all gastrointestinal symptoms result from food intolerance or hypersensitivity,” says Leung. “Sometimes there can be an intrinsic gastrointestinal disorder causing the problem, forexample chronic pancreatitis, inflammatory bowel disease, ulcerative colitis, or other gastrointestinal diseases.” People who think they are sensitive to gluten should speak with their healthcare provider before beginning a gluten-free diet.
Avoid gluten-containing foods if you have been diagnosed with celiac disease or non-celiac gluten sensitivity.