Gluten-free diets have been gaining popularity over the last several years, but is eliminating gluten actually beneficial to your health? Does gluten cause inflammation? Who should consider eliminating gluten?
Here, we answer these questions, breaking down the science behind gluten, and how it affects the health of different people. Our goal is to empower you with the facts, so you can make informed decisions about your health, including whether or not gluten should be a part of your diet.
What is gluten?
Gluten is a group of proteins found in certain grains including wheat, barley, rye, and triticale (a hybrid of wheat and rye). It can also be added to foods to enhance flavor and texture, as gluten is a structural protein that helps foods hold their shape. (1)
Common gluten-containing products and foods include certain grains, breads, baked goods, soups, pasta, pizza, cereals, soy sauce, food colorings, and other processed foods.
What to look for on a nutrition label: (2)
Wheat: (including semolina, durum, wheat berries, spelt, farina, farro, kamut, graham, couscous, bulgur)
Barley: (including all forms of malt, brewer’s yeast)
Rye: (including pumpernickel)
Oats: Oats are naturally gluten-free, however, cross-contact of certain grains can make them gluten-containing unless labeled Certified Gluten-Free
Does gluten cause inflammation?
Gluten does not appear to be inherently inflammatory. In fact, many gluten-containing foods, like whole, unrefined grains (think farro, bulgar, and other whole grain products), can be health-supportive, providing vitamins, minerals, protein and high fiber carbohydrates.
Digestive enzymes help to break down proteins like gluten, so they can be effectively digested. While certain by-products of gluten are not fully broken down, they can usually be processed in the intestines without causing digestive distress or inflammation in most people. (7)
However, there are certain conditions that can trigger inflammation when gluten is consumed including, celiac disease, non-celiac gluten/wheat sensitivity (NCGS or NCWS), and wheat allergies. These conditions can cause varying types and degrees of inflammation in the body when gluten is consumed, which can have negative implications on the digestive system and overall health. (7, 8)
Here is a closer look at the spectrum of gluten intolerances:
Celiac disease is a genetic, autoimmune disease that affects an estimated 1% of the U.S. population, which is about 2 million people (not accounting for the many people that go undiagnosed or misdiagnosed). (4, 3) It is considered the most severe of gluten intolerances, as it can cause significant, long-term intestinal damage and can lead to other complications such as malnutrition, nervous and immune system complications, and other chronic conditions. (5)
Symptoms of celiac disease can vary but typically include diarrhea or constipation, bloating and gas, and abdominal pain as well as other non-digestive symptoms like fatigue, headaches, peripheral neuropathy, joint pain, and menstrual disruption. (9) These symptoms are related to malabsorption due to damage to the small intestine lining, gut irritation, intestinal barrier permeability, and generalized inflammation. (14) However, some people with celiac disease may have little to no symptoms, and the age of symptom onset can vary greatly. (9)
Celiac disease can be diagnosed by a healthcare professional with lab testing and in some cases an endoscopy with intestinal biopsy. Currently, the only treatment for celiac disease is to avoid all gluten-containing foods and practice cross-contamination precautions. (10)
A wheat allergy is a specific reaction to wheat proteins that can cause an inflammatory response. These proteins include albumin, globulin, gliadin, and gluten.
In the case of a wheat allergy, the body will recognize the proteins in wheat as dangerous substances, and will produce antibodies against them. Unlike celiac disease and NCGS, a wheat allergy is not specific to gluten. (12)
The symptoms of a wheat allergy are similar to other common allergic reactions and can include itching, hives, congestion, headache, difficulty breathing, nausea/vomiting, diarrhea, and even anaphylaxis. Wheat allergies are most common in young children. However, some adults may continue to have, or even develop, wheat allergies, as they get older. (12)
Non-Celiac Gluten/Wheat Sensitivity (NCGS/NCWS)
Non-celiac gluten sensitivity (NCGS) is a condition in which someone has adverse reactions to gluten-containing foods, but does not have a positive test result for celiac disease or a wheat allergy. Because it can be harder to identify and diagnose, it can make treatment and the prevention of inflammation challenging.
Those with NCGS may experience symptoms similar to those with celiac disease after ingesting gluten, which may be related to gut irritation, increased permeability of the intestinal barrier, and inflammation. (14)
Symptoms may include diarrhea, gas, bloating, fatigue, “brain fog”, and abdominal cramps. Currently, the only way to diagnose NCGS is through an elimination diet. If someone has adverse reactions to gluten, has tested negative for celiac, and has symptom relief after eliminating gluten from the diet, they can be diagnosed with non-celiac gluten sensitivity. (6)
NCGS is not well understood and lacks definitive parameters for diagnosis. For example, someone may eliminate gluten from the diet and feel improvement in their symptoms, but it may be other components to the food actually causing the problem, such as foods high in FODMAPs.
FODMAPs, including wheat-based products, can be common triggers for gastrointestinal distress, particularly for those with IBS. (6, 11) Additionally, if someone cuts out highly processed, gluten-containing foods with high amounts of added sugar and saturated fats, in favor of more whole, plant-based foods, they may feel an improvement in their digestion and overall health, but it may not have to do with gluten specifically, but rather the nutritional composition of the diet.
If you are having symptoms of NCGS/NCWS, we recommend working with a Registered Dietitian Nutritionist to help identify the specific cause, so you can modify the diet accordingly.
(4) A note on other autoimmune disorders:
Because people with celiac disease have an increased risk of other autoimmune disorders, including arthritis, Hashimoto’s and multiple sclerosis (MS), sometimes gluten-free diets are recommended for these individuals. However, gluten-free diets are not established, therapeutic dietary interventions for these diseases at this time unless the individual has been diagnosed with celiac disease, a wheat allergy, or non-celiac gluten/wheat sensitivity. (15,13)
The bottom line on gluten:
Eliminating gluten from the diet seems to only be beneficial for those that are susceptible to the potentially inflammatory effects of gluten. This includes those that have celiac disease, a wheat allergy, or non-celiac gluten/wheat sensitivity (NCGS/NCWS), as those conditions can cause varying degrees of inflammatory responses when gluten is consumed.
For others, gluten-containing foods, such as whole grains, can be nutritionally dense, healthy additions to the diet. In general, you want to avoid eliminating certain food groups unless you have a medical condition or personal or cultural reason to do so, as you are limiting the scope of nutrients you can get from your diet, which can lead to deficiencies.
While a gluten-free diet can reduce gut dysbiosis, permeability, and inflammation in those with celiac disease, wheat allergies, or NCGS, it can actually negatively impact gut health in those without gluten intolerances. Research is limited, and there are many confounding variables in dietary studies, but some evidence shows that gluten-free diets in healthy individuals may reduce good bacteria in the gut, creating a more favorable environment for potentially harmful bacteria to grow. (16, 17)
If you tolerate gluten, meaning you do not notice any side effects when eating a gluten-containing food, then there is currently no strong evidence to support eliminating it. It is also important to note that gluten-free foods, including packaged foods, are not inherently healthier options, and can actually come with more added sugar and saturated fats, and less fiber and protein, depending on the product.
Whether you choose to go gluten-free or not, our recommendation remains the same on consuming a diet rich in fruits, vegetables, lean proteins, legumes, healthy fats, and whole grains. For those following a gluten-free diet, whole grains may include gluten-free oats, brown rice, and quinoa for example.
Have more questions about gluten? Work with a Culina Health Registered Dietitian Nutritionist to get personalized virtual nutrition care that is covered by insurance. Schedule a free intro call to get started!