Nutrition Science and Everyday Application - beta v 0.1

166 ALICE CALLAHAN, PHD, HEATHER LEONARD, MED, RDN, AND TAMBERLY POWELL, MS, RDN
Figure 3.20. Celiac disease is caused by an autoimmune response to gluten, found in wheat, rye,
and barley. At right is a section of the small intestine from a biopsy, visualized under a microscope,
from a celiac patient. The villi, which would normally be finger-like projections, are blunted and
flattened by damage caused by the disease.
Celiac disease is different from a wheat allergy in both cause and symptoms. Because
celiac disease is an autoimmune condition, the cells of the small intestine come under attack,
and damage causes chronic symptoms. A wheat allergy, on the other hand, is caused by
antibodies attacking an allergen in the wheat itself, and the symptoms are usually immediate
and acute.
Sometimes, people test negative for celiac disease but still believe that consuming gluten
is causing symptoms, usually gastrointestinal in nature. They may eliminate gluten from their
diet and find that they feel better. This is often called non-celiac gluten sensitivity (NCGS). It’s
not clear what causes NCGS or why a gluten-free diet is helpful. In some cases, it may be a
placebo effect. In others, it seems that it’s not gluten causing the problem but other dietary
components, such as FODMAPs, that happen to also be low in a gluten-free diet. And in
some cases, gluten does seem to cause symptoms in people without celiac disease, although
researchers don’t understand why. 11,12
Except in the case of celiac disease, wheat allergy, or confirmed NCGS, gluten-free foods
or a gluten-free diet are not inherently more healthful. In fact, packaged gluten-free foods
are often more highly processed, with more added sugar, salt, and fat, compared to foods
containing wheat. A gluten-free diet can also be lower in fiber, so those following the diet
should be sure to include naturally gluten-free whole grains, legumes, nuts, fruits, and
vegetables to provide adequate fiber. 13
Self-Check: