What is Gluten?

With millions suffering from gluten intolerances and coeliac disease, our awareness of gluten has risen substantially in recent years. But do you know what it actually is, how it can affect some people, and what gluten-free really means? Our nutrition team answer some of the most frequently asked questions on the topic.

Gluten refers to a group of proteins that are found in some, but not all, grains. These grains include wheat, barley, rye and tricale (a cross between wheat and rye). The two main gluten proteins are called gliadin and glutenin.

What does gluten do?

Gluten plays a major role in many bakery products. When you add water to flour the sticky dough texture is due to gluten^[1]. Gluten forms a network that holds water in the structure. Gliadin allows dough to rise during baking and fermentation by trapping air, which forms pockets^[2]. Glutenin gives dough its strength and elasticity^[2]. The more the dough is mixed, the stronger the gluten network becomes changing the final product texture from light and crumbly to chewy. So longer mixing is desirable for bread, but less so for cake. Without gluten, the well-loved characteristics of many bakery products lost. As gluten forms a complex network, it can be hard to replicate with other ingredients^[3].

What is coeliac disease and non-coeliac gluten sensitivity?

Coeliac disease is a chronic autoimmune condition^[4]. It occurs because the body detects gluten that is ingested as a threat, similar to a virus. As a result, antibodies are produced, particularly in the gut, that subsequently cause inflammation and damage the lining of the small intestine. The symptoms of coeliac disease include a variety of gut issues, fatigue, joint pain and micronutrient deficiencies, such as iron^[4]. Coeliac disease may only present a few general symptoms, so can go undiagnosed^[5]. If you feel you have such symptoms or a relative has coeliac disease, it’s important to schedule a screening to determine a proper diagnosis.

Non-coeliac gluten sensitivity (also known as gluten intolerance) is diagnosed when an individual experiences intestinal distress, headaches and fatigue, amongst other symptoms, as a result of consuming gluten-containing foods but has not been diagnosed with coeliac disease or wheat allergy, although some symptoms may overlap^[6]. Self-diagnosis does not mean an individual has gluten sensitivity. In fact, many people who are self-diagnosed may have another dietary issue unrelated to gluten^[7] or no issues at all^{[7, 8]}. It has been found that of those who are self-diagnosed with gluten sensitivity as little as 7% may actually have symptoms as a result of gluten consumption^[8].

Another chronic autoimmune condition caused by gluten is called dermatitis herpetiformis. It is often linked to coeliac disease but has a lower prevalence in the population of approximately 0.03%^[9]. Dermatitis herpetiformis is characterised by itchy blisters/rashes, most commonly found on the elbows, knees and buttocks^[10].

Are people avoiding gluten unnecessarily?

It depends on the individual. If you have coeliac disease, wheat allergy or non-coeliac gluten sensitivity then the answer is no. Around 1% of the population are coeliac^[11]. It is highly likely that the number of people with non-coeliac gluten sensitivity is higher in the general population; however, due to self-diagnoses and lack of medical consultation there is considerable debate around the number of people affected by non-coeliac gluten sensitivity^[12]. The average figure appears to be approximately 6%^[13]. If you do not have any of the aforementioned conditions, then you do not need to avoid gluten. If you feel you might, it is important to get a professional medical diagnosis. Additionally, a dietitian will be able to ensure your diet and health do not suffer as a result of avoiding certain foods.

If someone doesn’t need to avoid gluten and does, are there any benefits?

Beyond managing gluten-related disorders the answer is no; in fact, a gluten-free diet can have negative consequences as a result of dietary restriction. It has been shown to result in an inadequate intake of fibre and magnesium, along with several other micronutrients^{[14, 15]} and an increase in sugar consumption^[16]. People who follow a gluten-free diet may well have a nutritious diet, however, it’s important to understand that eliminating certain foods does not automatically make a diet more nutritious. The reason that a gluten-free diet can have such consequences is that some gluten-free products may be higher in sugar and fat while being low in wholegrains^[17].

Furthermore, gluten-free alternatives tend to be over twice as expensive as their gluten-containing counterparts^[18] while being of a lower quality, particularly in terms of texture^[17].

Is gluten-free a fad?

It’s hard to define what a fad diet is, without pointing to examples, even though the term has existed for over 100 years^[19]. If someone is looking towards a gluten-free diet to improve the quality of their diet or for weight loss, then eliminating gluten is unlikely to help directly.

For those who must avoid gluten because of a dietary condition it is certainly not a fad. The increase in media coverage of “gluten-free” has improved the availability and variety of gluten-free options^[20]. It has also made “gluten-free” a more present sign on food labels. On the other hand, it has created more confusion around what coeliac disease is and how that differs from those who choose not to eat gluten for other reasons^[20].

What foods are gluten-free?

Most foods are gluten-free. This includes meat, poultry, nuts, seeds, dairy and fruit and vegetables. Although the most commonly consumed grains contain gluten, not all do. Some examples of gluten-free grains are corn, oats, buckwheat and quinoa. It’s important to note that grains naturally free of gluten may become contaminated during growing or processing if they come into contact with gluten-containing grains.

Processed foods can contain gluten when you may not expect them to, such as soy sauce. Although the labelling of gluten-free foods is not required there are laws surrounding it. A food can only be labelled as gluten-free if it contains 20ppm or less^[21].

How are gluten-free foods made?

To ensure all ingredients are gluten-free they must be grown in a separate, controlled environment. Different crops can often be grown in neighbouring fields or in the same field one after another, which can result in gluten contaminating naturally gluten-free crops. Once harvested the ingredients must be transported, handled and packed in a gluten-free environment. This may involve an entirely separate factory or a different part of the same factory where separate equipment and clothing is used. Additionally, a thorough cleaning procedure and adequate time (over 24 hours) between handling gluten-containing and gluten-free ingredients must be in place.

Gluten-free flours including tapioca, rice and corn flours can be used in replacement of gluten-containing flours, namely wheat flour. Additional ingredients such as emulsifiers to improve mixing, fibres for thickening and hydrocolloids to bind water may be added to a food that traditionally would contain gluten to replicate its varied functions^[17].

Are oats gluten-free?

Oats are naturally gluten-free. However, as mentioned above they are an example of a grain that can become contaminated with gluten. As a result, oats are often certified as suitable for people with coeliac disease by being grown and processed in a gluten-free environment^[22]. Around 8% of those with coeliac disease appear to have a reaction to gluten-free oats^[23]. This may be due to avenin. Avenin is another prolamin protein similar in structure to gluten which can cause an autoimmune response.

Gluten-free certification

Gluten-free certification is a way of confirming to consumers that a food, drink or supplement meets rigorous standards for gluten-free safety. Certification is obtained through third-party assurance which ensures that a manufacturer’s gluten-free processes and claims are correct.

There are multiple organisations that provide gluten-free certification with their own criteria that need to be met to be able to use their certification. The largest and most recognised in the EU is the Association of European Coeliac Societies (AOECS). Some of AOECS' criteria include having all products tested using a UKAS or equivalently accredited laboratory and having production facilities undergo approved audits. The certification needs to be renewed on a yearly basis. The Crossed Grain Symbol (see below) is a clear way for consumers to recognise that a product is certified “gluten-free” by AOECS.

Are Huel products gluten-free?

Most, but not all of our products are gluten-free. Our Black Edition Powder, Daily A-Z Vitamins, RTD and Complete Protein are all naturally gluten-free, so are safe to consume if you are coeliac. We offer gluten-free versions of Huel Powder v3.1 in vanilla, chocolate and salted caramel flavours which you can find here. All gluten-free Huel products contain less than 20ppm which is confirmed by batch testing.

References

1. Biesiekierski JR. What is gluten? Journal of gastroenterology and hepatology. 2017; 32 Suppl 1:78-81.

2. Barak S, et al. Influence of Gliadin and Glutenin Fractions on Rheological, Pasting, and Textural Properties of Dough. International Journal of Food Properties. 2014; 17(7):1428-38.

3. Watson F, et al. Gluten-Free Baking 2017. Available from: https://routt.extension.colostate.edu/wp-content/uploads/sites/4/2018/05/9.376-Gluten-Free-Baking.pdf.

4. NHS. Coeliac disease. Date Accessed: 30/10/19. [Available from: https://www.nhs.uk/conditions/coeliac-disease/causes/]

5. Rubio-Tapia A, et al. Increased prevalence and mortality in undiagnosed celiac disease. Gastroenterology. 2009; 137(1):88-93.

6. Leonard MM, et al. Celiac Disease and Nonceliac Gluten Sensitivity: A Review. Jama. 2017; 318(7):647-56.

7. Biesiekierski JR, et al. No Effects of Gluten in Patients With Self-Reported Non-Celiac Gluten Sensitivity After Dietary Reduction of Fermentable, Poorly Absorbed, Short-Chain Carbohydrates. Gastroenterology. 2013; 145(2):320-8.e3.

8. Lionetti E, et al. Re-challenge Studies in Non-celiac Gluten Sensitivity: A Systematic Review and Meta-Analysis. Frontiers in Physiology. 2017; 8(621).

9. West J, et al. Incidence and prevalence of celiac disease and dermatitis herpetiformis in the UK over two decades: population-based study. The American journal of gastroenterology. 2014; 109(5):757-68.

10. NHS Inform. Dermatitis herpetiformis. Date Accessed: 30/10/19. [Available from: https://www.nhsinform.scot/illnesses-and-conditions/skin-hair-and-nails/dermatitis-herpetiformis]

11. Singh P, et al. Global Prevalence of Celiac Disease: Systematic Review and Meta-analysis. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association. 2018; 16(6):823-36.e2.

12. Catassi C, et al. Non-Celiac Gluten sensitivity: the new frontier of gluten related disorders. Nutrients. 2013; 5(10):3839-53.

13. Sapone A, et al. Spectrum of gluten-related disorders: consensus on new nomenclature and classification. BMC Medicine. 2012; 10(1):13.

14. Tavakkoli A, et al. Characteristics of patients who avoid wheat and/or gluten in the absence of Celiac disease. Digestive diseases and sciences. 2014; 59(6):1255-61.

15. Vici G, et al. Gluten free diet and nutrient deficiencies: A review. Clinical nutrition (Edinburgh, Scotland). 2016; 35(6):1236-41.

16. Wild D, et al. Evidence of high sugar intake, and low fibre and mineral intake, in the gluten-free diet. Alimentary pharmacology & therapeutics. 2010; 32(4):573-81.

17. El Khoury D, et al. A Review on the Gluten-Free Diet: Technological and Nutritional Challenges. Nutrients. 2018; 10(10).

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

19. Diet and Diet Fads. The Hospital. 1908; 45(1160):173-4.

20. King JA, et al. Experiences of coeliac disease in a changing gluten-free landscape. Journal of human nutrition and dietetics : the official journal of the British Dietetic Association. 2019; 32(1):72-9.

21. EU. Commission Implementing Regulation (EU) No 828/2014 Official Journal of the European Union; 2014.

22. Gilissen LJWJ, et al. Why Oats Are Safe and Healthy for Celiac Disease Patients. Medical sciences (Basel, Switzerland). 2016; 4(4):21.

23. Hardy MY, et al. Ingestion of oats and barley in patients with celiac disease mobilizes cross-reactive T cells activated by avenin peptides and immuno-dominant hordein peptides. Journal of Autoimmunity. 2015; 56:56-65.