Beth MacIntosh is nutrition research and metabolism core project director at the N.C. Translational and Clinical Sciences Institute at UNC-Chapel Hill. Questions and answers have been edited.
Q: What is gluten?
Gluten is a protein found in wheat, barley and rye. Common gluten-containing foods include pastas, breads and cereals.
Q: What kinds of conditions affect a person’s ability to tolerate gluten? What happens in the digestive tract of people with these conditions when they ingest gluten?
Celiac disease, celiac sprue, nontropical sprue, gluten-sensitive enteropathy or gluten sensitivity are all conditions that make people intolerant or sensitive to gluten. In a healthy intestine, the intestine wall is covered with finger-like projections called villi. The villi increase the surface area, thereby enhancing the ability to absorb nutrients and release enzymes for digestion. In untreated celiac disease, the villi are partially or totally flattened. Over time this damage can trigger symptoms including abdominal cramping, bloating, diarrhea, constipation, joint pain, weight loss, infertility and fatigue. Because the disease causes damage to the intestine, it influences the absorption of vitamins and minerals and may also lead to nutrient deficiencies.
Q: Gluten-free products seem to be appearing everywhere these days – does this mean that gluten intolerance is on the rise or that gluten-free diets are becoming trendy?
The prevalence of celiac disease has increased, and studies indicate that it now affects about 1 out of every 133 people. It is estimated that 95 percent of those with the disease go undiagnosed and that it often takes up to 10 years to get the correct diagnosis. On top of that, food companies are taking advantage of the opportunity to put a new label on their product. Many foods that are labeled as gluten-free were always gluten-free, and others have been reformulated to be gluten-free.
Q: Are gluten-free diets inherently healthy? Do they really have weight-loss benefits beyond addressing food sensitivity?
No, gluten-free diets do not have any benefits for those who are not intolerant or sensitive to gluten. A gluten-free diet has not been proven to be effective for weight loss. While there are still plenty of tasty foods to eat on a gluten-free diet, it can be very challenging to follow. In addition, many products that contain gluten are important sources of B vitamins, so people on a gluten-free diet need to eat carefully planned, balanced meals in order to maintain vital nutrient intake.