Currently NICE, states if a patient is experiencing symptoms pointing to CD (including gastrointestinal distress and prolonged fatigue), tests for the presence of immunoglobulin A (IgA) and IgA tissue transglutaminase (tTG) are required, with positive results then indicating the need for an intestinal biopsy to confirm diagnosis. (2)

 A gluten free diet is then required as treatment to alleviate symptoms. In some cases, symptoms continue. In this instance, it could be the individual has non-responsive or refractory CD, and alternative tests will need to be carried out.

The BDA released an article in 2023 commenting on the imbalance between the proportion of individuals consuming a gluten free diet and those needing to adhere to a gluten free diet due to CD. (3) This came after a resurfacing of information around gluten sensitive individuals, which had subsided for multiple years, since initial findings in the 1980s. (4) (5) These individuals present with symptoms of CD - yet upon diagnostic testing, markers for CD are not present.

One theory for this, is evidence suggesting gluten sensitive individuals have an innate immune reaction to gluten whereas in CD there is both an innate and adaptive immune response. Yet, so far, there have been no antibodies associated with this to confirm the theory. (6) However, fructans - found in wheat, a component of the FODMAP foods, alongside amylase trypsin inhibitors (ATIs) - proteins found in seeds of cereals, including gluten - are seen to stimulate an innate immune response. (7)

It has been found a low-FODMAP diet, often advised to individuals with irritable bowel syndrome (IBS) experiencing similar symptoms to those with CD, is beneficial as dietary treatment for those who believe they are sensitive to gluten . However, in this instance it would actually be the wheat or ATIs they are sensitive to, producing the innate reaction and not gluten. Moving forward in the article, reference to any potential sensitivities will be under the umbrella of gluten.

It has also been found that 20% of gluten sensitive individuals filled the Rome III criteria used for IBS diagnosis compared to 3.89% of non-gluten sensitive individuals. (8) This then poses the question as to whether individuals who are stating an intolerance to gluten actually have IBS or if distinguishing between the two in the diagnosis stage is just challenging.

In 2015, the Salerno Experts’ criteria were developed for the attempted diagnosis of gluten sensitivity, separate to IBS, the test follows two stages. In the first stage the patient consumes a gluten containing diet to gain baseline symptom levels, then at time point zero, a gluten free diet is consumed for 6 weeks to determine changes in symptoms from the gluten containing diet. A symptomatic response is deemed valid when there is a difference of at least 30% from the baseline score.

Stage two is the gluten challenge, where a Double-Blind Placebo-Controlled Challenge with crossover is carried out, meaning the patient and dietitian do not know when gluten will be consumed as a rechallenge strategy to confirm diagnosis. (9) This criterion is useful, however far from practical considering the varying symptoms patients report. (10)

Regardless of how gluten sensitivities are diagnosed, it is useful to know the low-FODMAP diet can be applied to a patient as it is practical application to support symptoms alleviation. However, it is important to know in the long term whether a GF diet due to sensitivity could increase the risk of developing other diseases- which will then complicate dietary management- so far not the case in IBS. (11)

Gluten free foods contain reduced levels of vitamins B and D, as well as lower levels of iron, zinc, calcium, magnesium and fibre. Furthermore, wheat is a large source of protein for many individuals,6 and so removal could reduce daily protein intake. Additionally, there has been evidence to suggest gluten free diets can increase intake of higher glycaemic index foods, lipids and sodium.12

Therefore, when discussing a gluten free diet regardless of whether the patient does or does not have CD, there must be education around foods leading to weight gain and susceptibility to potential deficiencies.

Encouraging food diversity through education, can reduce both potential problems. However, it has been shown the cost of a gluten free diet is a lot higher than a gluten containing one,13 hence more financial burden is associated to those trying to stick to the diet alongside supporting their overall health.

In recent years there has been more commentary on a food shortage due to conflict, climate and economic changes and so the need to adapt staple crops such as wheat is a rapidly growing field. Through genetic modification, gluten can be adapted to improve product quality. (14). However, a focus on adaption to feed highly populated developed or developing countries adopting a gluten free diet could have more beneficial effects in years to come.