That definitely is true for someone who has celiac disease, because as we previously explained, the autoimmune disorder prevents the person from absorbing nutrients unless he or she avoids gluten. But for most of us, gluten isn't going to have that effect. And avoiding gluten actually may lead to a less nutritious diet if you're not careful. For most people, whole wheat flour is a major source of dietary fiber, so gluten-free dieters risk not getting enough unless they make an effort to replace it with sources such as fruits, vegetables, beans and brown rice [source: Strawbridge].
Additionally, conventional products, like your typical loaf of wheat bread, often are enriched with nutrients such as iron, calcium, thiamine, riboflavin and folate. When you avoid those grain products, you may also get lesser amounts of those nutrients, unless you take a vitamin supplement to counteract the loss. Additionally, cutting out gluten may cause a decrease in beneficial bacteria in the gut, which can have a negative impact on your immune system [sources: UW Health, Strawbridge].