Part 1: Wheat vs Gluten – Medical Perspective

4 July 2022. By FACTS in Allergen Management, Regulatory & Nutrition

FACTS receives many inquiries about the ‘significant cereal’ group, also called ‘gluten-containing’ cereals elsewhere in the world. We sympathetically refer to this as ‘Wheat vs Gluten confusion’. The goal of this four-part series is to help you go from confusion to clarity.
In part 1, we look at the medical perspective: who is affected, how, and why.

Why is there confusion?

We’re sure that – as for most things in life – there are many answers to this. But it seems there may be two main reasons:

Not everyone in the food industry understands why consumers avoid significant cereals, and that not every consumer has the same reason. For example, some consumers only avoid wheat, while others avoid all of the significant cereals because they contain gluten.
The consolidation of four different cereals into a single group – ‘significant cereals’ – promotes the idea that these cereals trigger a single adverse food reaction.

What is meant by ‘significant cereals’?

This is a group name used by the South African regulations relating to the labelling and advertising of foodstuffs (R. 146/2010) to describe the edible seeds of wheat, rye, barley, oats and their crossbred hybrids.

What is the significance of these cereals?

They contain proteins that trigger adverse reactions in sensitive individuals and make up one of the common allergens regulated in South Africa.

Each significant cereal contains many proteins. Some proteins are allergenic, or can trigger the body’s immune system. Some are specific to a particular cereal and trigger allergic reactions; whereas the protein gluten, present in wheat, rye and barley, viewed by the immune system to be identical, triggers coeliac disease (CD) symptoms in genetically susceptible individuals.

Wheat is a major allergen, meaning it triggers allergic reactions in a significant number of individuals. Although rye, barley and oats can also trigger allergic reactions, they do so in a less significant number of consumers. As gluten is present in all these cereals, they present a risk to all gluten-affected individuals.

THE SOUTH AFRICAN REGULATIONS RELATING TO THE LABELLING AND ADVERTISING OF FOODSTUFFS (R. 146/2010)

IMPORTANT DEFINITIONS

‘significant cereal’ means any one of the following cereals:

Wheat, meaning any species belonging to the genus Triticum, including varieties such as kamut and spelt;
Rye, meaning any species belonging to the genus Secale;
Barley, meaning any species belonging to the genus Hordein;
Oats; or
Crossbred hybrids of wheat, rye or barley (e.g. triticale, which is a cross between wheat and rye).

‘common allergen’ means egg, cow’s milk, crustaceans and molluscs, fish, peanuts, soya beans, tree nuts and any significant cereals, as well as any ingredient derived from these foodstuffs that has retained its allergenicity in the final product.

So, what is gluten?

From a functional point of view, gluten plays a key role in the structural properties of baked goods, such as bread and pasta. Gluten is the collective name for the storage proteins found in the endosperm of wheat, rye, barley and oats. It is a protein that consists of two linked protein subunits, glutelins and prolamins. The prolamins found in wheat (gliadin), rye (secalin) and barley (hordein) are rich in proline and glutamine amino acids, while avenin (oats) contains lesser amounts. Although these proteins are all different, they contain both individual and common immunoreactive epitopes (parts of the protein that bind with specific antibodies, triggering an adverse reaction). Some epitopes trigger allergic reactions, and others CD. Avenin seems to be different, in that it is tolerated by most CD patients.

Why are oats included in the significant cereal group?

As mentioned above, although oats are a significant cereal they do not trigger adverse reactions in the bulk of individuals with CD. Thus, if oats are pure – meaning not contaminated with other significant cereals – they may be classified as a gluten-free grain, and safe for CD patients. However, it has been shown that a small subgroup of patients (fewer than 5%) may be intolerant to pure oats. Moreover, in practice oats are almost always unavoidably contaminated with considerable amounts of wheat, rye or barley. Thus, oats are classified as a significant cereal.

Which conditions are triggered by significant cereals?

Aside from CD, which has a prevalence of approximately 1%, 20 to 45 of every 100 adults with a self-reported food sensitivity believes it is due to gluten. The role that different food components play in bringing about gastrointestinal (GI) symptoms (a common complaint) is a complex one, and our understanding of all its triggers is incomplete. Thus, gluten is unlikely to be the only culprit in such a large group of individuals.

The thin line between CD, irritable bowel syndrome (IBS) and non-coeliac gluten sensitivity (NCGS) is not always clearly distinguishable, making it difficult to differentiate between them.

As alluded to earlier, disorders related to the significant cereal group are broadly categorised into allergic reactions (e.g. wheat allergy), autoimmune reactions (e.g. CD) and reactions that do not involve the immune system (wheat/gluten intolerance).

Let’s have a closer look at the most prominent disorders:

Wheat allergies are an immune-mediated reaction to wheat proteins, and the onset of symptoms is normally acute (i.e. rapid onset). Even minute amounts of the wheat present in a product can cause an allergic reaction, and symptoms range from mild skin, gastrointestinal or respiratory symptoms to potentially life-threatening anaphylaxis in severe cases. Individuals with wheat allergies must follow a strict wheat-free diet to avoid reactions.

Coeliac disease (CD), also called celiac disease, is a lifelong autoimmune systemic disorder, triggered by gluten, that leads to the progressive deterioration of the lining of the small intestine.

Individuals with classic CD present with signs and symptoms of food malabsorption (diarrhoea, abdominal pain, bloating, wind, distension, weight loss or growth failure). In non-classic CD, non-specific signs and symptoms (iron deficiency anaemia, osteoporosis, fatigue) or even asymptomatic presentation are now accepted to be common. The presentation may feature one or more of the above symptoms, with high or low intensity.

Patients with long-term, neglected CD have elevated risk for the development of cancers, diabetes, infertility, adverse pregnancy outcome, impaired bone health (including osteoporosis) and mortality. In children, CD may be associated with growth failure and delayed puberty.

For CD patients, introducing a gluten-free diet can lead to significant improvement in symptoms, abnormal biochemical measures, and quality of life. A lifelong gluten-free diet is the only way to avoid the symptoms and complications of the disease. Because a small subgroup of patients with CD may also be intolerant to pure oats, there is reluctance in some countries to advise liberal consumption of oats, because it is difficult to guarantee that commercially available oats will be free of contamination from other grains.

Whether or not oats are safe to consume has been debated for years. As mentioned above, in general, oats themselves may be safely consumed by individuals with CD; but they may be contaminated by wheat, and pure, uncontaminated gluten-free oats are often not available.

The safe limit for gluten intake varies from patient to patient. It was long considered to be 10 to 100mg/day, although a later study has indicated that the upper limit should be no more than 50mg/day.

Non-coeliac wheat sensitivity (NCWS), also called non-coeliac gluten sensitivity, is difficult to diagnose; its exact aetiology (cause) is broadly unknown, and its relationship with other disorders such as IBS is murky. NCWS symptoms include IBS-like intestinal and extra-intestinal manifestations (lethargy, fatigue, skin rash, gynaecological troubles, headache, joint and muscle pain, leg or arm numbness, anaemia, depression, anxiety, psychosis), which start a few hours or days after exposure to wheat gluten and resolve when wheat and gluten are removed from the diet. An NCWS diagnosis is only proposed when other conditions such as CD, wheat allergies, autoimmune conditions, lactose and fructose intolerance, inflammatory bowel disease and pancreatic insufficiency have been excluded.

To reiterate: wheat contains many proteins. Some proteins trigger wheat-allergic reactions, while gluten (one of the proteins in wheat) triggers CD symptoms in genetically susceptible individuals. Individuals with wheat allergies need to avoid only wheat; those with CD should avoid wheat, rye, barley and oats.

In closing, it seems many in our community diagnose themselves as being gluten sensitive, when in fact they don’t suffer from that condition; but for those with a real problem with gluten and wheat, even a low level of exposure can have serious immediate and/or long-term health effects. Manufacturers therefore have a responsibility to take the intentional or accidental presence of gluten and wheat in their products seriously, and our regulations have clear guidelines for this. If you want to learn more, read the rest of this series. Should you have any queries regarding allergen claims, allergen management or testing, please don’t hesitate to contact us.