Think it’s gluten-free? Why some foods can still pose risks for coeliacs

Lupine porridge with dried fruits and blueberries. Photo / Getty Images

Question:

As a coeliac, I’m looking at buying lupin-containing foods, which most online searches say contains no gluten. However, Christchurch-based Gerry’s Bakeries says on its website its Lupin Power Flakes product contains gluten, even though lupin is gluten-free.

Answer:

Lupin is a legume available in several forms,
including whole beans, kernels, bran and flour. These ingredients can be used in baked goods, cereals, sauces, desserts and confectionery. Although it is not yet widely used in New Zealand foods, it may become more common because lupin flour is naturally high in fibre and protein, and is gluten-free.

Indeed, lupin has a distinctly different nutritional profile to other legumes, being low in starch. Studies suggest it supports satiety, improves blood pressure and may improve cholesterol markers and blood sugar control, although more research is needed.

So, why would lupin flakes be listed as containing gluten? First, it’s helpful to distinguish between gluten and allergens. Lupin is closely related to peanuts and soybeans; it is considered an allergen particularly because people with a peanut allergy may also react to it.

For this reason, local food manufacturers must declare lupin on food labels, just as they must declare other major allergens such as wheat, egg, milk, fish and peanuts.

Gluten must also be declared when present, but it is not classified as an allergen in the same way.

Gluten is a protein found in wheat, rye, barley, spelt and triticale (a hybrid of wheat and rye). It gives dough its elastic, stretchy properties and helps baked goods maintain their structure, chewy texture and airy volume. This is desirable for many foods, but gluten poses a serious problem for people with coeliac disease, an autoimmune condition in which ingestion of gluten triggers inflammation and damage to the small intestine.

The inner surface of a healthy small intestine is lined with tiny, finger-like projections known as villi, which increase the surface area for nutrient absorption. In coeliac disease, gluten exposure damages and flattens these villi, reducing the body’s ability to absorb nutrients effectively. During time, this can lead to deficiencies in iron, folate and calcium.

Symptoms of coeliac disease can include diarrhoea, fatigue, weakness, lethargy, anaemia (due to iron or folate deficiency) and abdominal bloating. Symptoms can extend to flatulence, cramping, nausea and vomiting, and in some people, weight loss. In children, untreated coeliac disease can lead to poor growth, delayed development and irritability.

Given your diagnosis, strictly avoiding gluten is essential. Although lupin is naturally gluten-free, contamination can occur during harvesting, transport or processing. For example, lupin may be handled in facilities that also process wheat or other gluten-containing grains, allowing trace amounts of gluten to be transferred via shared equipment, storage systems or transport containers.

This appears to be the most likely explanation for the situation with Gerry’s Lupin Power Flakes: although lupin itself does not contain gluten, the finished product may contain small amounts due to cross-contamination. (Gerry’s Bakeries did not respond to the Listener’s request for comment.)

For a similar reason, manufacturers of oats do not make gluten-free claims on the package, even though oats naturally contain no gluten. Oats do contain a protein called avenin that is structurally similar to gluten; a small percentage of people with coeliac disease do react to this.

Under the Food Standards Code in New Zealand, to be labelled “gluten-free” a product must contain no detectable gluten, oats or oat products, and no cereals containing gluten that have been malted, or their derivatives. This strict threshold is designed to ensure the safety of people with coeliac disease.

If traces of gluten might be present through cross-contamination, manufacturers may voluntarily indicate this on the label with wording such as “May contain gluten” or “Made in a facility that also processes wheat”.

It is certainly possible that not all lupin products are off limits for coeliacs: for example, some forms (such as flour) may be produced under stricter controls and tested to meet gluten-free standards while others are not.

For coeliac consumers, the presence of a formal “gluten-free” label remains the most reliable guide.

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