This post is part of the “To Try or Not to Try” blog series. Written by a registered dietitian (RD) or dietetic intern, each post explores the claims and science surrounding a different dietary pattern or trend. After compiling this research, each RD or RD2be gave the diet a grade based on whether it appears to hold up to the hype. A = “yes, go for it!” and F = “no way, absolutely not!”
About the Author:
Emily Rowe, RD works at Carilion Roanoke Memorial Hospital as a Pediatric Dietitian. She obtained her undergraduate degree from Virginia Tech and completed her dietetic internship through the University of Massachusetts, Amherst.
What is a gluten-free diet recommended for?
To begin, gluten is simply a protein found in wheat, rye and barley. Within the medical community, the gluten-free diet is primarily used as a treatment for celiac disease, a hereditary autoimmune disorder. In fact, the only way to manage celiac disease is through the complete removal of dietary gluten. For those with celiac disease, the consumption of gluten causes an immune response that attacks the small intestinal villi, which are small fingerlike projections that help absorb nutrients. If people with celiac disease fail to follow a gluten-free diet, the small intestinal villi will be severely damaged, become flat, and consequently will no longer be able to absorb nutrients properly; this leads to nutrient deficiencies. People living with non-celiac gluten sensitivity also benefit from the removal of gluten from their diet. Non-celiac gluten sensitivity involves similar symptoms of celiac disease, but an absence of the antibodies and intestinal damage seen in those with celiac disease (1-3). The effectiveness of a gluten-free diet for treating conditions such as arthritis, irritable bowel syndrome, and autism has not been scientifically proven (4-7).
Many people within the mainstream community believe the gluten-free diet is a quick fix solution to help them lose weight or get healthy. However, weight loss successes while following a gluten-free diet are commonly attributed to the removal of high-calorie gluten containing foods (like baked goods and pastries), which can be achieved without going gluten-free (8,9).
What foods are allowed on a gluten-free diet?
As stated in the name of this trendy diet, the “gluten-free diet” must be free of gluten-containing products. Some are more obvious and easy to identify, such as wheat, rye, and barley and foods commonly made with these products (crackers, baked goods, pastas, breads, cereals and breading mixes). Less obvious sources of gluten include processed lunch meats, salad dressings, candy bars, gravies, soups, malt beverages, and soy sauces. Even non-food products such as lipsticks, lip gloss, herbal/vitamin supplements, and some over the counter drugs can contain gluten. In order to be sure the foods you eat are gluten free, refer to a food’s ingredients list and avoid cross contact with gluten-containing foods. For further questions regarding what foods to avoid and what foods are “safe” to include, speak with a registered dietitian (1,10).
What is the overall nutrient composition?
The only modification is the removal of gluten-containing grains and food products; thus, a gluten-free diet doesn’t propose a specific macronutrient distribution. Adequate carbohydrates, fat, and protein can be obtained from a variety of foods to achieve the macronutrient distribution suggested by the Dietary Guidelines for Americans.
However, due to the removal of wheat, barley, and rye, those who choose to exclusively follow a gluten-free diet may increase their risk of inadequate intake of certain micronutrients. The FDA regulates the enrichment and fortification of numerous food products, some of which naturally contain gluten. Enrichment is the process of returning specific nutrients to foods that have been lost while being prepared or processed. For example, wheat naturally contains many important micronutrients such as iron and B vitamins. During the process of refining whole wheat flour to white flour, these valuable nutrients are lost; the enrichment process adds them back. Many gluten-containing products such as wheat flour and cereals are subject to fortification, meaning that additional valuable nutrients are added to improve the nutritional quality of food. The FDA has requirements of standardized foods that must be fortified, which include cereals, bakery products, bread, rolls, buns, and macaroni products. Unfortunately, many gluten-free products are not enriched or fortified with the vitamins and minerals that gluten-containing grain products are. As a result, deficiencies in these vitamins and minerals can occur in those who remove gluten from their diet (11,12).
Are the claims about a gluten-free diet supported by science?
It is well established that a gluten-free diet is the only way to manage celiac disease, as the consumption of gluten is the cause of the immune response that damages the intestines of people with this condition. People living with non-celiac gluten sensitivity have also been found to benefit from the removal of gluten from their diet (1-3).
Unfortunately, as previously mentioned, there is no scientific evidence to support that simply removing gluten from the diet results in weight loss. Research studies have shown both weight gain and weight loss on a gluten free diet. Additional research has also noted an increase in BMI and waist circumference with a decrease in whole grain intake, a common side effect to gluten removal. In most cases, weight loss successes while following a gluten free diet are commonly attributed an overall calorie deficit (8,9).
Additionally, the strength of the evidence varies and further research is needed to draw accurate, definitive conclusions on whether a gluten-free diet is useful in treating conditions such as arthritis, irritable bowel syndrome, and autism (4-7).
Who should definitely not try a gluten-free diet?
While removing gluten from your diet may not result in any drastic weight changes or greatly improve your overall health (sans those with celiac disease), it also doesn’t appear to have any negatives for any specific individual. The diet still allows for an appropriate macronutrient distribution. As long as one stays cognizant of micronutrient and fiber intake, this diet can be followed by anybody with no obvious detrimental long-term or short-term effects.
Is a gluten-free diet realistic and sustainable?
The gluten-free diet is a conundrum in how it is both sustainable and realistic for people to follow, but also appears to have some negative consequences for the environment. On the individual level, following this diet has become easier each year with the development of many gluten-free products and the increase in societal awareness. At one point in time, eating out at restaurants was close to impossible for those following a gluten-free diet, but now most restaurants carry gluten free alternatives to our favorite gluten-containing foods. The only downside to the individual is the cost increase of many gluten-free products.
On the environmental side, the shift towards lower carbohydrate diets and gluten-free grains appears to have some negative planetary effects. For example, the increase in popularity of gluten free grains such as quinoa has begun to put strain on the environment in the form of soil erosion and the spreading of pests and disease in the attempt to keep with the demands. Of course, it is important not to overlook the economic benefits for quinoa farmers who on average appear to be better off financially as a result of the increased demand for the grain.
Additionally, with an elimination of many carbohydrate foods, a shift to higher meat consumption commonly occurs. The environmental resources required for cattle and other livestock is much higher than what is needed to grow plants. The most mentionable differences being the amount of land and water. For example, a pound of beef requires about 1,851 gallons of water to produce while the same amount of rice only requires 300 gallons of water. The main take away message in terms of sustainability and reality when it comes to the gluten-free diet is to eliminate gluten when necessary, but continue to try and include a large variety of whole grains such as brown rice, corn, quinoa and sorghum with meals (17,18).
What are the overall pros and cons of a gluten-free diet?
For people with celiac disease, a gluten-free diet is extremely beneficial in that it prevents inflammation, intestinal damage, and malabsorption. It can also decrease symptoms in people with non-celiac gluten sensitivity.
However, some research shows it can have less than desirable effects if one is not knowledgeable on how to compensate for the subsequent removal of certain nutrients when gluten is eliminated. For example, gluten free diets have been associated with higher risks of type 2 diabetes due to decreased fiber intake — a known protective factor in preventing this condition. Along the same lines of decreased fiber intake, some studies have also revealed a negative correlation with fiber intake and BMI/waist circumference. As previously mentioned, a gluten-free diet could also result in micronutrient deficiencies due to the lack of fortification of gluten-free food products. Thus, if one chooses to follow this diet for any reason, they should meet with a medical professional/registered dietitian to ensure it is followed correctly and healthily (8,19).
A gluten-free diet may also adversely affect the gut microbiota. While the ideal diet for gut microbiota is not fully understood, in general, fiber is considered beneficial for gut health. Due to a common lack of fiber intake in people who follow a gluten-free diet, it may put them at an increased risk of developing alterations in gut bacteria. Some research has discovered that a gluten-free diet may decrease the bacteria that plays an important role in the metabolism of starch and an increase in a strain of bacteria that is more bile-tolerant. This is likely a result of changes in environment and resources for the bacteria allowing some strains to thrive and others to die off. Further studies may provide better insight to the benefits or disadvantages of the gluten-free diet on the health and quality of the gut mircobiome (13-16).
It is also important to note that gluten-free food products can sometimes be more expensive and less palatable than their traditional counterparts.
What grade do you give a gluten-free diet?
For individuals with celiac disease or non-celiac gluten sensitivity, I give this diet an A+ and recommend it to be followed strictly for their health. On the other hand, in terms of outcomes such as weight loss, I give the diet a D. At this time, the is no research/scientific consensus that suggests tremendous benefits of following a gluten-free diet for conditions such as autism, IBS or weight loss. In fact, there are much healthier, cheaper, and effective ways to lose weight.
What is your general recommendation for a healthy eating pattern for the average human?
As a registered dietitian, my general recommendation for a healthy eating pattern for the average person is centered around moderation. While it’s no surprise that certain foods have much a greater nutritional value than others, I believe that a healthy eating pattern can include all foods. Instead of having a mindset that focuses on restricting foods, macronutrients or certain food groups, I believe the goal should be to increase nutrient dense foods and consume all other foods in smaller amounts. Nutrient dense foods such as fruits, vegetables, lean meats and fish, beans/legumes, nuts, dairy products with no added sugar, and whole grains contain essential vitamins, minerals, proteins and fatty acids as well as other valuable nutrients such as fiber. These foods should make up a significant amount of a person’s daily intake, but should also not be consumed in excess. Other foods which don’t fall into the category of “nutrient dense” due to a lack of necessary nutrients, or an overall minimal nutritional benefit, should be limited and only make up a small portion of a person’s daily intake. This should set up a good base for an overall healthy eating pattern, but other important aspects of health including regular exercise, mindful eating and adequate sleep should not be overlooked.
This content is intended for informational and educational purposes only. It is not intended as medical advice, medical nutrition therapy, or individualized nutrition counseling. Talk to your doctor or another licensed healthcare practitioner before making any changes to your diet, medications, or exercise routine. The opinions of these authors are their own and are not approved, sponsored, or endorsed by any professional organizations including but not limited to the Academy of Nutrition and Dietetics, United States Department of Agriculture, Food and Drug Administration, National Institutes of Health, American Heart Association, and American Diabetes Association.