• The Listener
  • North & South
  • Noted
  • RNZ

The dangers of the 'gluten challenge'

Photo/Getty Images

If you have to do a gluten challenge before being tested for coeliac disease, beware of side effects.

Adopting a gluten-free diet before getting a definitive diagnosis of coeliac disease can be harmful to your health. This was the experience of Wellingtonian Iain Girvan, who suffered joint pain after reintroducing gluten into his diet after five months without it. The pain was so severe that he was on crutches for a month and had to work reduced hours from home.

What made matters worse for the 40-year-old public-sector consultant, was that he had to resume eating gluten to get an accurate diagnosis of coeliac disease. He’s been left wondering whether his decision to eat a gluten-free diet may have contributed to the pain that he is  still experiencing months later.

“It’s almost like the gluten challenge has kind of broken something, and I haven’t recovered.”

Girvan’s journey to his coeliac diagnosis started several years ago. The autoimmune condition affects the small intestine and is triggered by consuming gluten, a protein found in wheat, barley, rye and oats. Common symptoms include chronic diarrhoea or constipation, abdominal bloating, cramping, wind, tiredness, weakness, lack of energy, weight loss, nausea and vomiting.

Macro alias: ModuleRenderer

In Girvan’s case, it was less specific: “I started feeling kind of unwell; I had a stuffy nose, like a cold that wouldn’t go away, almost like a low-level flu, but not something you could pinpoint.”

It took three years of doctor’s visits and a barrage of tests to establish that he was positive for coeliac antibodies. It came as a surprise to Girvan, who has no family history of coeliac disease.

However, the blood test can’t provide a definitive diagnosis. The only way to get one is by having a biopsy to check for damage to the lining of the small intestine.

Girvan’s GP referred him for the procedure last August. “And he said, ‘Go gluten-free and then do the biopsy’, which turns out is not great advice.”

The official advice is to keep eating gluten until after a formal diagnosis of coeliac disease, because a gluten-free diet can affect the accuracy of blood tests and biopsies. Nonetheless, many people start a gluten-free diet without first getting a formal diagnosis.

Girvan started his diet unaware that the biopsy referral had been “lost in the system”. After submitting another referral, he was scheduled to have his biopsy in April. By that time, he had been on a gluten-free diet for five months and was feeling a lot better. “I had some energy back, I wasn’t feeling as sick and my concentration was a lot better.”

However, he needed to reintroduce gluten (a process known as a “gluten challenge”, in which a normal diet is resumed before testing, with the aim of eating about 10g of gluten a day) for an accurate diagnosis, something Girvan had reservations about doing, because he was feeling well.

The deciding factor was the need to confirm he had coeliac disease so he could access treatment.

Girvan completed the gluten challenge for three weeks, enjoying an extended “last supper” that included fish and chips, beer, doughnuts and pizza. But with the gluten-containing diet came the old symptoms of brain fog and lethargy, along with new and unexpected joint pain.

The biopsy confirmed his diagnosis of coeliac disease and Girvan immediately reverted to a gluten-free diet, which is the only way to manage the condition.

Months later, he is feeling slightly better, but still takes painkillers three or four times a day. He is unsure if another health problem underlies his now-chronic pain, but having taken the hard route to his diagnosis, he strongly recommends listening to the official advice.

This article was first published in the July 13, 2019 issue of the New Zealand Listener.