How Healthy is a Gluten-Free Diet?

Twenty one percent of Americans report cutting gluten from their diets. Estimated sales of gluten-free foods in the United States have increased from $3.8 billion in 2011 to $10.5 billion in 2015. Some foods have gluten-free labels only to take advantage of this interest because they have never contained gluten. Many supermarkets now have gluten free sections. The most common reason why people report eating gluten-free foods is because they believe gluten-free is healthier.

Are gluten-free foods really healthier?

Gluten is a protein found in wheat, barley and rye. These foods are harmful to people with three conditions. The first is celiac disease in which the body reacts to gluten in a way that damages the small intestines. This affects about 1 percent of people. The second is wheat allergy that is usually an allergic reaction to non-gluten proteins in wheat. This also affects about 1 percent of people. The last condition is called non-celiac gluten sensitivity (NCGS) for which the cause is unclear. People with NCGS typically have symptoms that can occur with many other diseases such as fatigue, foggy mind and abdominal bloating. One estimate is this affects 5-10 percent of people. There is currently no test to determine if you have NCGS.

Doctors advise everyone with celiac disease and wheat allergy to avoid foods that contain gluten. Gluten-free foods are more expensive. Following a gluten-free diet is difficult. In a study of 82 patients with celiac disease, only 30 percent were able to pass a quiz on the gluten content of 17 common foods. The nutritional content of gluten-free foods is often worse than foods containing gluten. There is a risk of B vitamin and folic acid deficiency with a gluten-free diet.

Many people attempting for follow gluten free diets are concerned about NCGS. Since there is no test for NCGS, people often try a gluten-free diet to see if they feel better.  Feeling better is not always reliable. When people with possible NCGS are given a double blind challenge with either a placebo or gluten, many people get worse with the placebo. In one study, 68 percent of people with NCGS got worse after a gluten challenge while 40 percent got worse with a placebo. This worsening is primarily caused by the placebo response. Other research suggests food additives may be the actual cause for many NCGS symptoms.

The evidence indicates that 7-12 percent of people in the United States can benefit from avoiding gluten. Unfortunately, there is no standard test for the most common condition, NCGS. This means you may have to avoid gluten for a month to see if you feel better and then decide if you are benefiting from avoiding gluten. Ideally, you should also try gluten again to see if the symptoms recur before making a final decision. There is currently no scientific evidence that there is a health benefit for all people to avoid gluten.

Selected References

1. What you should know about America’s gluten-free fad: http://myfox8.com/2016/07/14/what-you-should-know-about-americas-gluten-free-fad/
2. Gluten-free sales statistics: http://www.statista.com/topics/2067/gluten-free-foods-market/
3. Khalid An, McMains KC: Gluten sensitivity: fact or fashion statement? Current Opinion in Otolaryngology & Head and Neck Surgery. 2016 June; 24(3):238-40.
4. Silvester JA, Weiten D, Graff LA, Walker JR, Duerksen DR: Is it gluten-free? Relationship between self-reported gluten-free diet adherence and knowledge of gluten content of foods. Nutrition. 2016 July-August; 32(7-8):777-83.
5. Foschia M, Horstmann S, Arendt EK, Zannini E: Nutritional therapy – Facing the gap between celiac disease and gluten-free food. International Journal of Food Microbiology 2016 June 15.
6. Cruchet S, Lucero Y, Cornejo V.: Truths, Myths and Needs of Special Diets: Attention-Deficit/Hyperactivity Disorder, Autism, Non-Celiac Gluten Sensitivity, and Vegetarianism. Annals of Nutrition and Metabolism. 2016; 68 Suppl 1:43-50.
7. Molina-Infante J, Santolaria S, Sanders DS, Fernández-Bañares F. Systematic review: non-coeliac gluten sensitivity. Alimentary Pharmacology & Therapeutics, 2015; 41:807–20.