What’s The Deal With Gluten?

What’s The Deal With Gluten?

Gluten is a protein found in wheat, rye, and barley. It is actually a pretty cool glue like protein that holds foods together and results in that gooey consistency that people love in baked goods. Contrary to what I and many others once thought based on gluten’s lower digestibility score, it may not actually be that bad for muscle protein synthesis [1].

What many people don’t know is that a gluten-free diet is not going to result in more weight loss when we control for calories and protein, and gluten-free products are definitely not automatically healthier [2].

In fact, gluten-free products tend to be 2 to 3 times more expensive and many times are higher in calories and lower in fiber and protein than their gluten containing counterparts [3-7].

So, if you don’t have celiac disease or any digestive symptoms it is probably not in your best interest nutritionally or socially to militantly avoid gluten.

Now, what if you are worried that you have celiac disease or an autoimmune or digestive problem with gluten?

First, celiac disease is for sure a thing and it appears to affect 0.7 to 1.4% of people depending on how it is diagnosed [8]. For a thorough review of the pathophysiology and diagnostic criteria of celiac disease see the review by Leonard et al., 2017 in JAMA [9] or the review by Caio et al., 2019[10].

A lifelong gluten-free diet is currently the only viable treatment for celiac disease, although not all individuals with celiac disease respond to a gluten-free diet [11] and the threshold of gluten tolerance seems to be highly individual and debated [12].

Additionally, many people who think they are following a gluten free diet are probably encountering small amounts of gluten [13, 14] and to truly consume a diet completely void of gluten is likely very difficult [15], but does look to be possible [16].

“Following a gluten-free diet for treatment of celiac disease was reportedly more burdensome than treatments for type 1 diabetes, IBS, inflammatory bowel disease, and congestive heart failure. Those with end-stage renal disease on hemodialysis were the only group to report a higher treatment burden than those with celiac disease.” 

-Silvester et al., 2021 [11]

What’s even more vehemently debated is whether non-celiac gluten sensitivity (NCGS) or non-celiac wheat sensitivity (NCWS) are real or even independently caused by gluten and/or wheat [17-23].

A recent systemic review and meta-analysis of gluten re-challenge studies in individuals with NCGS by Lionetti et al., 2017 found that there was no real significant difference in the percentage of patients that responded to gluten versus a placebo [24].*

This may leave many to the knee-jerk reaction that NCGS or NCWS aren’t even real, but what’s clear is that these individuals have digestive symptoms and/or problems outside of their gastro intestinal tract.

The real culprit here may be something called FODMAPs which are fermentable carbohydrates that are also found in wheat [19, 25, 26]. However, it is important to note that there are highly individually variable responses here and some people are certainly reactive to gluten [23].

This subject is extremely complex and involves a lot of acronyms and fancy words. What I think is unhelpful is the over simplification that gluten is BAD and everyone should avoid it or that gluten is not a problem and everyone can just eat it.

The first step if someone believes they have a problem with gluten is to undergo testing for celiac disease and a wheat allergy with a qualified medical professional.

Even if celiac disease testing comes back negative a lower FODMAP diet and gluten-free diet may be initiated. If these dietary changes alleviate symptoms a double-blind gluten challenge (without FODMAPs) can help potentially identify the culprit and a reintroduction of FODMAPs may be initiated at 4 to 6 weeks to potentially find someone’s individual FODMAP tolerance. These types of dietary changes should probably not be done reactively or without the help of an extremely knowledgeable professional who is also aware of the problems associated with the noceboes and placebos of this realm.

“In general, the implementation of a GFD and a low-FODMAP diet in NCGS patients should be considered if improvement of clinical manifestations is seen, but medical and dietitian advice is recommended to prevent any nutritional deficiencies that could appear due to the dietary restrictions.” 

-Cárdenas-Torres et al., 2021 [27]


*“The overall pooled percentage of patients with a diagnosis of NCGS relapsing after a gluten challenge was 36% as compared to 31% relapsing after placebo (p = 0.2) which is statistically non-significant. [However], the overall pooled percentage of patients with a diagnosis of NCGS relapsing after a gluten challenge performed according to the Salerno criteria was significantly higher as compared to the percentage of patients relapsing after placebo (40 vs. 24%; p = 0.003)”. [24]


1. Pinckaers, P.J.M., et al., No differences in muscle protein synthesis rates following ingestion of wheat protein, milk protein, and their protein blend in healthy, young males. Br J Nutr, 2021. 126(12): p. 1832-1842.

2. Marcason, W., Is there evidence to support the claim that a gluten-free diet should be used for weight loss? J Am Diet Assoc, 2011. 111(11): p. 1786.

3. Vici, G., et al., Gluten free diet and nutrient deficiencies: A review. Clin Nutr, 2016. 35(6): p. 1236-1241.

4. Taetzsch, A., et al., Are Gluten-Free Diets More Nutritious? An Evaluation of Self-Selected and Recommended Gluten-Free and Gluten-Containing Dietary Patterns. Nutrients, 2018. 10(12).

5. Missbach, B., et al., Gluten-free food database: the nutritional quality and cost of packaged gluten-free foods. PeerJ, 2015. 3: p. e1337.

6. Melini, V. and F. Melini, Gluten-Free Diet: Gaps and Needs for a Healthier Diet. Nutrients, 2019. 11(1).

7. Diez-Sampedro, A., et al., A Gluten-Free Diet, Not an Appropriate Choice without a Medical Diagnosis. J Nutr Metab, 2019. 2019: p. 2438934.

8. Singh, P., et al., Global Prevalence of Celiac Disease: Systematic Review and Meta-analysis. Clin Gastroenterol Hepatol, 2018. 16(6): p. 823-836 e2.

9. Leonard, M.M., et al., Celiac Disease and Nonceliac Gluten Sensitivity: A Review. JAMA, 2017. 318(7): p. 647-656.

10. Caio, G., et al., Celiac disease: a comprehensive current review. BMC Med, 2019. 17(1): p. 142.

11. Silvester, J.A., A. Therrien, and C.P. Kelly, Celiac Disease: Fallacies and Facts. Am J Gastroenterol, 2021. 116(6): p. 1148-1155.

12. Catassi, C., et al., A prospective, double-blind, placebo-controlled trial to establish a safe gluten threshold for patients with celiac disease. Am J Clin Nutr, 2007. 85(1): p. 160-6.

13. Abu-Janb, N. and M. Jaana, Facilitators and barriers to adherence to gluten-free diet among adults with celiac disease: a systematic review. J Hum Nutr Diet, 2020. 33(6): p. 786-810.

14. Stefanolo, J.P., et al., Real-World Gluten Exposure in Patients With Celiac Disease on Gluten-Free Diets, Determined From Gliadin Immunogenic Peptides in Urine and Fecal Samples. Clin Gastroenterol Hepatol, 2021. 19(3): p. 484-491 e1.

15. Syage, J.A., et al., Determination of gluten consumption in celiac disease patients on a gluten-free diet. Am J Clin Nutr, 2018. 107(2): p. 201-207.

16. Monachesi, C., et al., Quantification of Accidental Gluten Contamination in the Diet of Children with Treated Celiac Disease. Nutrients, 2021. 13(1).

17. Koumbi, L., O. Giouleme, and E. Vassilopoulou, Non-Celiac Gluten Sensitivity and Irritable Bowel Disease: Looking for the Culprits. Curr Dev Nutr, 2020. 4(12): p. nzaa176.

18. Mumolo, M.G., et al., Is Gluten the Only Culprit for Non-Celiac Gluten/Wheat Sensitivity? Nutrients, 2020. 12(12).

19. Dieterich, W. and Y. Zopf, Gluten and FODMAPS-Sense of a Restriction/When Is Restriction Necessary? Nutrients, 2019. 11(8).

20. Sabenca, C., et al., Wheat/Gluten-Related Disorders and Gluten-Free Diet Misconceptions: A Review. Foods, 2021. 10(8).

21. Catassi, C., et al., Diagnosis of Non-Celiac Gluten Sensitivity (NCGS): The Salerno Experts' Criteria. Nutrients, 2015. 7(6): p. 4966-77.

22. Sergi, C., V. Villanacci, and A. Carroccio, Non-celiac wheat sensitivity: rationality and irrationality of a gluten-free diet in individuals affected with non-celiac disease: a review. BMC Gastroenterol, 2021. 21(1): p. 5.

23. Whelan, K., FODMAPs or gluten as inducers of symptoms in irritable bowel syndrome: separating the wheat from the chaff. Am J Clin Nutr, 2022. 115(2): p. 327-328.

24. Lionetti, E., et al., Re-challenge Studies in Non-celiac Gluten Sensitivity: A Systematic Review and Meta-Analysis. Front Physiol, 2017. 8: p. 621.

25. Nordin, E., et al., Fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), but not gluten, elicit modest symptoms of irritable bowel syndrome: a double-blind, placebo-controlled, randomized three-way crossover trial. Am J Clin Nutr, 2022. 115(2): p. 344-352.

26. Mohseni, F., et al., The effect of low FODMAP diet with and without gluten on irritable bowel syndrome: A double blind, placebo controlled randomized clinical trial. Clin Nutr ESPEN, 2022. 47: p. 45-50.

27. Cardenas-Torres, F.I., et al., Non-Celiac Gluten Sensitivity: An Update. Medicina (Kaunas), 2021. 57(6).