Gluten-free diets have gained significant attention and popularity in recent years, with around 20% of consumers in the US at least occasionally purchasing foods and products marketed as gluten-free (which tend to be considerably more expensive) when shopping1,2. However, while a small proportion of people with gluten-related conditions do need to avoid gluten, for the vast majority, gluten and gluten-containing whole grains are highly beneficial. In fact, going gluten-free is considered unnecessary and may even have unintended adverse consequences.
What Is Gluten?
Gluten is a family of proteins, known as prolamins, naturally found in wheat, barley, and rye grains. Although gluten is often thought of as a single compound, it is in fact a collective term that refers to several different proteins with similar structures and properties in these grains — primarily gliadin and glutenin in wheat, hordein in barley, and secalin in rye.
How Common Are Gluten-Related Conditions?
There is a small percentage of people who can certainly benefit from eliminating gluten from the diet. For instance, celiac disease is an autoimmune disorder where the body’s immune system attacks its own tissues when gluten is consumed, which can damage the villi of the small intestine and interfere with the absorption of nutrients from food. The prevalence of celiac disease is estimated to be between 0.5% and 1.4% in North America3 — significantly lower than the prevalence of peanut allergy4.
A further 1-6% in the US may have non-celiac gluten sensitivity, a milder form of gluten intolerance5. It’s important to note that these estimates are largely based on self-diagnoses, because unlike celiac disease, there is a lack of reliable biomarkers for non-celiac gluten sensitivity. That means the estimates can be confounded by, for instance, the fact that symptoms produced by consumption of gluten-containing foods, especially ultra-processed foods like cakes and pastries, may not be attributable to the gluten itself6.
Is Gluten Healthy for Adults Without Gluten-Related Conditions?
For the vast majority of the population without celiac disease or gluten intolerance, avoiding gluten can be a mistake. As well as the starchy carbohydrates they contain which can help fuel exercise, gluten-containing whole grains are a significant source of fiber, protein, healthy fats, vitamins, minerals, and numerous beneficial phytochemicals7,8. In fact, there is comprehensive research that higher intake of whole grains, including wheat, barley and rye, is associated with:
- Lower blood pressure and reduced risk of cardiovascular disease
- Reduced risk of gastrointestinal cancers10,11
- Reduced risk of diabetes12
- Lower body fat13
The evidence strongly suggests that the vast majority of the population could miss out on the myriad health benefits of various whole grains by following a gluten-free diet14. The health benefits are so well documented that the WHO recommends consuming whole grains every day as part of their Healthy Diet guidelines15, and the USDA recommends adults consume 6-10 ounce equivalents of grains daily16.
As well as the benefits of other nutrients contained in whole grains, several studies suggest that gluten itself can be health-promoting. For instance, studies show that introducing additional gluten to the diet can improve blood lipids17, and gluten may also play a specific role in reducing blood pressure18.
Regarding gut health, a randomized controlled trial published in the journal Gastroenterology found no difference in gastrointestinal symptoms between healthy participants following a gluten-free diet who were randomly allocated to introduce gluten-free or organic gluten flour into the diet19. Looking more closely at the gut microbiome, a study published in Gut Microbes found that adherence to a gluten-free diet resulted in fewer healthy gut bacteria and greater numbers of unhealthy bacteria. Fecal samples of subjects consuming the gluten-free diet also exerted lower immune stimulatory effects than those of subjects on a regular gluten-containing diet20.
Should Athletes Consider a Gluten-Free Diet?
Compared to the general population, an even greater proportion of athletes follow a gluten-free diet, even in the absence of celiac disease or non-celiac gluten sensitivity. Most athletes do this in the belief that it could improve athletic performance, but there is a distinct lack of scientific evidence to support these assumptions21.
For instance, a double-blind placebo-controlled crossover trial examined the effects of a 7-day gluten-free or gluten-containing diet on 15-minute time trial performance. All food was provided, except for fresh fruit and vegetables, and habitual exercise was replicated between trials, with 16 grams per day of either gluten or placebo (whey protein) provided in an indistinguishable food bar. There was no statistical difference between treatments for cycling performance, gastrointestinal issues, overall wellbeing, or inflammatory markers22.
In fact, several potential negative effects of excluding gluten on performance have been identified, resulting from excessive food restrictions, including decreased energy and nutrient intake, and suboptimal fueling23. As a result, athletes excluding gluten unnecessarily could also be at increased risk for musculoskeletal injuries, iron-deficiency anemia, hormonal imbalances, and immune suppression24.
In terms of recovery, a recent randomized, double-blind, parallel-group design study assessed muscle protein synthetic response to 30 grams of wheat protein versus 30 grams of milk protein in young males. They took blood and muscle biopsies repeatedly for five hours following consumption and found no difference in muscle protein synthesis rates25 (studies comparing whey protein with other plant proteins like soy, pea and rice proteins have found similar results).
The Take Home Message
For those with celiac disease or non-celiac gluten sensitivity, avoiding gluten is usually the best course of action. But for the vast majority of adults, gluten and gluten-containing whole grains are highly beneficial, with higher consumption being associated with reduced risk of several important chronic diseases. Some of these benefits may be attributed directly to gluten itself, as well as the fiber and other nutrients contained in whole grains. Meanwhile, excluding gluten from the diet unnecessarily can result in reduced dietary quality, which can negatively impact both health and performance.
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- Statista (2022). Gluten Free Purchase Habits United States, accessed June 2023: https://www.statista.com/statistics/1329606/gluten-free-purchase-habits-united-states/
- Lee, A. R., Wolf, R. L., Lebwohl, B., Ciaccio, E. J., & Green, P. H. R. (2019). Persistent Economic Burden of the Gluten Free Diet. Nutrients, 11(2), 399. https://doi.org/10.3390/nu11020399
- Singh, P., Arora, A., Strand, T. A., Leffler, D. A., Catassi, C., Green, P. H., Kelly, C. P., Ahuja, V., & Makharia, G. K. (2018). Global Prevalence of Celiac Disease: Systematic Review and Meta-analysis. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association, 16(6), 823–836.e2. https://doi.org/10.1016/j.cgh.2017.06.037
- Warren, C., Lei, D., Sicherer, S., Schleimer, R., & Gupta, R. (2021). Prevalence and characteristics of peanut allergy in US adults. The Journal of allergy and clinical immunology, 147(6), 2263–2270.e5. https://doi.org/10.1016/j.jaci.2020.11.046
- Igbinedion, S. O., Ansari, J., Vasikaran, A., Gavins, F. N., Jordan, P., Boktor, M., & Alexander, J. S. (2017). Non-celiac gluten sensitivity: All wheat attack is not celiac. World journal of gastroenterology, 23(40), 7201–7210. https://doi.org/10.3748/wjg.v23.i40.7201
- Sabença, C., Ribeiro, M., Sousa, T., Poeta, P., Bagulho, A. S., & Igrejas, G. (2021). Wheat/Gluten-Related Disorders and Gluten-Free Diet Misconceptions: A Review. Foods (Basel, Switzerland), 10(8), 1765. https://doi.org/10.3390/foods10081765
- Barbaro, M. R., Cremon, C., Stanghellini, V., & Barbara, G. (2018). Recent advances in understanding non-celiac gluten sensitivity. F1000Research, 7, F1000 Faculty Rev-1631. https://doi.org/10.12688/f1000research.15849.1
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