Gluten-free foods: the hype of the modern-day man.

Much has been said and written about gluten. This has contributed, as is often the case in nutrition, to an abundance of controversial information circling the internet.

Increased awareness of medical conditions related to gluten has given rise to the gluten-free trend capturing many people’s attention in the social space. Beyond their established therapeutic role, gluten-free diets are now widely promoted as a means to improve gut health, enhance mental clarity, increase energy levels, and support bone health [1].

Introduced as the panacea for general digestive problems and tummy aches, this is not only a trending hashtag in social media, but a rapidly growing industry branch, and a lifestyle marketed by a myriad of social influencers online.

However, a gluten-free diet is inherently restrictive and could potentially have unwanted side-effects in the absence of a medical indication. Hence, the need to understand the science behind its effects.

Does a gluten-free diet truly benefit healthy individuals?

But first, what is gluten? The condensed version.

Gluten is the name of a complex mixture of different proteins found in cereals. It is further classified into two fractions, prolamins – a group of simple proteins that are responsible for the dough’s stickiness and ability to stretch – and glutenins, which play a role in the elasticity and strength. Interestingly, prolamins have different names depending on the plant species. For instance, the prolamins found in wheat are called gliadins; in barley - hordeins; in rye – secalins; in oats - avenins and the list goes on.

You can imagine gluten as the continuous viscoelastic protein network that forms when these two protein fractions are mixed with water, e.g., while baking. This is important because it shows a complex biophysiological picture of gluten as an important structural element, rather than a homogeneous substance.

Cereals have been part of human civilization since the dawn of agriculture. Comprising the primary source of plant-based protein in our diets, they are integrated in both food and feed production chains and build the backbone of the agricultural industry [2]. About half of the global dietary energy is provided by cereals [3], which is relevant when trying to exclude them entirely from your diet.

On the good side, not all cereals contain high amounts of gluten. There are even some that are naturally gluten-free such as corn, rice, sorghum, and pseudocereals like quinoa, amaranth, and buckwheat. However, the market dominance of gluten-rich cereals like wheat, barley, and rye is due to the desired characteristics they bring for food processing. From bread, to sauces, gravies, soups, and beverages like beer, when avoiding gluten, one must be careful of its prominent role as a food additive.

Disease trigger and gut invader

Gluten-related disorders (GRD) are chronic conditions related to the physiological reactions of the human body to gluten. There are 5 officially recognised GRDs - celiac disease (CD), non-celiac gluten sensitivity (NCGS), gluten ataxia, dermatitis herpetiformis (a chronic autoimmune skin condition), and wheat allergy – and they all differ in the underlying pathophysiological mechanisms that they trigger in the body.

For instance, whereas celiac patients experience a strong immune reaction that damages their small intestine lining, non-celiac gluten-sensitive people have the symptoms of a food allergy without the autoimmune reaction behind it. In contrast, wheat allergy triggers a potentially severe allergic reaction to wheat proteins, not exclusive to gluten.

As the underlying mechanisms differ drastically between GRDs, diagnosing them is not a simple feat [4]. Classic symptoms often overlap with other widespread conditions, like irritable bowel syndrome (IBS) or inflammatory bowel disease (Crohn’s disease). It takes time to isolate them properly before deciding on the appropriate diagnostic tests[BI1]

These, among other factors, contribute to an increase in self- or misguided diagnosis with GRD among Western societies. The most striking numbers being reported from the USA, where almost one-third of adults prefer to reduce or avoid gluten consumption, while the estimated prevalence of celiac disease, the most frequent GRD, remains 1 percent[BI2] [5]. The prevalence of CD in Europe is in the range between 0.2 and 3 percent, depending on region [6].

Why is it then that the gluten-free industry is growing disproportionately to the numbers of diagnosed GRD patients?

The rise of gluten-free as a lifestyle

A rising awareness of gluten’s pathological effects and a constantly improving food technology sector make up for the perfect combination for a thriving and expanding market. Even though prices of gluten-free products remain on average higher than their conventional counterparts, the choices of gluten-free foodstuffs and even cooked food options are growing.

The affordability of a fully gluten-free diet - if all products were replaced with their gluten-free market alternatives – will account for 42 to 60% of the monthly income of low-income families, according to a study from Cyprus [7], and is considered unaffordable for three of the four types of families commonly observed in Australia [8]. Additionally, given the limited product assortment despite recent improvements, and perceived taste differences, choosing the gluten-free lifestyle carries the risk of significantly restricting a person’s dietary options and cooking opportunities.

Nonetheless, gluten-free brands are growing their portfolio of products, supermarkets are introducing specially dedicated aisles, and increasingly restaurants are trying to adapt their menus to include gluten-free options, even though we are far from a fully ‘celiac-safe’ menu.

With an average of 8 thousand active social media profiles driving on the gluten-free train and an average of 17 thousand social posts per month [9], it is safe to say that your personalised algorithm will be safely supplied with the gluten-free information it needs.

In numerical terms, the ”gluten-free” phenomenon is feeding into a billion-dollar industry, valued at 7.4 billion USD globally in 2024 and projected to more than double by 2032 (15.4 billion USD) [10]. This development is also fuelled by the advance of diets that minimise the consumption of carbohydrates generally, such as low-carb or keto diets.

Against the backdrop of this growing industry, what does this mean for healthy individuals caught in the algorithm loop of the gluten-free lifestyle?

Effects of a gluten-free diet on healthy individuals.

Let us get to the core of the subject and dive straight into the science. A randomised, controlled, cross-over trial involving 60 Danish adults found alterations in the intestinal microbiome in the group with low gluten consumption. Specifically, 14 intestinal bacterial species were altered, out of which 11 decreased, particularly Bifidobacterium species [11]. This is in line with other studies findings [12]. However, no health effects were observed associated with this reduction.

Other studies focusing specifically on the biological value of Bifidobacteria in the human microbiome, underline their vital role in vitamin production and the antimicrobial defence of the gut [13]. Overall, Bifidobacteria species are considered integral parts of the human body, contribyting to the diversity and reamrkable teancity of the bacterial population residing in us.

However, back to the question of gluten, the microbiome changes appear to be driven by the differences in dietary fibre from the alternative cereals, and not by the absence of gluten specifically, which is yet again, consistent with other studies [14].

Improvements in bloating and subjective well-being were also reported. But scientists cannot say with certainty whether this was due to the microbiome changes, fermentation differences, or placebo effects, and long-term impact remains unknown [11].

These findings are consistent with other short-term studies, which have observed differences in immune system stimulation. Specifically, both the production of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-8), as well as anti-inflammatory cytokines (IL-10) was reduced, which may be linked to the reduced numbers of Bifidobacterium species [14], mentioned above. Cytokines are important mediators for the immune system that serve as signals when tissue is being attacked, is growing, or needs repair. Overall, a low gluten diet seems to dampen the microbiota-driven immune signalling, due to its lower fibre intake.

Furthermore, a gluten-free diet is often perceived as beneficial for weight loss. An analysis by Kim et al. using data from the National Nutrition US Survey (NHANES) from 2009 to 2014 examined adults without celiac disease who followed a gluten-free diet and found that, over one year, these individuals experienced modest weight loss, reduced waist circumference, and higher levels of high-density lipoprotein cholesterol compared with the general population. However, no significant differences were observed in the prevalence of metabolic syndrome or other cardiovascular risk factors [15]. As the study was retrospective in design, its findings indicate associations rather than a direct causal relationship between a gluten-free diet and these health outcomes. Generally, evidence behind the claim of gluten-free being beneficial against cardiovascular disease is scarce and not conclusive.

What is more, studies have found that many gluten-free products are not fortified and may lack key nutrients such as dietary fibre, folate, iron, niacin, riboflavin, and thiamine [16]. In addition, analyses of processed gluten-free foods have shown that these products often contain higher amounts of fat, including trans fats, as well as increased protein and salt levels when compared with similar foods that contain gluten [17][18]

Regarding bone health, publications have been exclusively focused on celiac patients. Due to a lack of information, it is not possible to extrapolate these results to healthy populations.

Overall clinical data is sparse and inconsistent, and there is no consensus on the benefits that a gluten-free diet may bring to a healthy individual. Therefore, we should be careful with the promises and claims circling online. Propagated and multiplied through myriads of channels, it is hard to trace back the original sources of the information.

Conclusion

Because eliminating gluten removes many commonly consumed foods, a gluten-free diet can increase the risk of nutritional deficiencies, particularly in B vitamins, fibre, and iron, thus negatively affecting gut health and reducing beneficial intestinal bacteria. Proper nutrition counselling is advised.

What is more, adhering to a gluten-free diet can reduce enjoyment and convenience of eating while substantially increasing food costs. Although more and more nutrient-dense gluten-free options are becoming available, the long-term health effects of maintaining a strict gluten-free diet in individuals without celiac disease remain unclear.

It appears that the majority of people following the trend do not have the physiological requirement to do so, and according to science likely do not experience any substantial gains from the absence of gluten specifically. It is advisable to carefully evaluate whether such dietary restrictions are necessary before recommending a gluten-free diet to someone, or deciding to follow it oneself, potentially imposing avoidable limitations.

References

[1]	Factor75, “5 Benefits of Eating a Gluten-Free Diet”.
[2]	C. Marinangeli, M. Nosworthy and A.-K. Shoveller, “Cereal proteins in the human diet: Reflecting on their contributions to daily protein intake,” Journal of Cereal Science, 2024.
[3]	Poutanen et al., “Grains – a major source of sustainable protein for health,” Nutrition Reviews, 2022.
[4]	Taraghikhah et al., “An updated overview of spectrum of gluten-related disorders: clinical and diagnostic aspects,” BMC Gastroenterology, 2020.
[5]	E. Watson, “30% of US adults trying to cut down on gluten, claims NPD Group,” Food Navigator USA, 2017. [Online]. Available: https://www.foodnavigator-usa.com/Article/2013/03/08/30-of-US-adults-trying-to-cut-down-on-gluten-claims-NPD-Group/.
[6]	Mustalahti et al., “The prevalence of celiac disease in Europe: results of a centralized, international mass screening project.,” Ann Med., 2010.
[7]	Chrysostomou et al, “The development of the gluten free healthy food basket in Cyprus. Is it affordable among low-income adults diagnosed with celiac disease?,” J Public Health (Oxf.), 2020.
[8]	K. Lambert and C. Ficken, “Cost and affordability of a nutritionally balanced gluten-free diet: Is following a gluten-free diet affordable?,” Nutrition & Dietetics, 2015.
[9]	SproutSocial, “Unlock the power of gluten-free influencer marketing,” 2025.
[10]	Fortune Business Insights, “Gluten-free Food Market Size, Share & Industry Analysis, By Type (Baby Food, Pastas & Pizzas, Snacks & RTE Products, Bakery Products, and Condiments & Dressings), By Distribution Channel (Supermarkets/Hypermarkets, Convenience Stores, Specialty Stores, Dr,” 2025.
[11]	Hansen et al, “A low-gluten diet induces changes in the intestinal microbiome of healthy Danish adults,” Nature communications, 2018.
[12]	De Palma et al, “Effects of a gluten-free diet on gut microbiota and immune function in healthy adult human subjects,” British Journal of Nutrition2009.
[13]	N. Devika and K. Raman, “Deciphering the metabolic capabilities of Bifidobacteria using genome-scale metabolic models,” Scientific Reports.
[14]	Y. Sanz, “Effects of a gluten-free diet on gut microbiota and immune function in healthy adult humans,” Gut Microbes, 2009.
[15]	Kim et al, “Obesity, Metabolic Syndrome, and Cardiovascular Risk in Gluten-Free Followers Without Celiac Disease in the United States: Results from the National Health and Nutrition Examination Survey 2009-2014,” Dig Dis Sci., 2017.
[16]	Vici et al, “Gluten free diet and nutrient deficiencies: A review,” Clinical Nutrition, 2016.
[17]	T. Kulai and M. Rashid, “Assessment of Nutritional Adequacy of Packaged Gluten-free Food Products,” Can J Diet Pract Res., 2014.
[18]	H. Staudacher and P. Gibson, “How healthy is a gluten-free diet?,” British Journal of Nutrition.