The first part of this interview appeared in the Apr/May 2013 issue of Paleo Magazine.
Jessica Biesiekierski was always interested in the relationship between diet and health, so when she was offered a scholarship to Melbourne Australia’s esteemed Monash University, she accepted without hesitation. She focused her research on the health effects of dietary carbohydrates called FODMAPs and has won awards from the Australian Gastroenterology Society and the Nutrition Society of Australia for her work. While in the middle of submitting her PhD thesis, Jessica took the time to talk to us about her research and to discuss some of it’s practical implications.
(Tony) What are your thoughts on the self-diagnosis of something like celiac disease?
(Jessica) Worldwide, there is an increasing number of people without celiac disease claiming to be gluten sensitive. My PhD research has found that 45% of self-perceived non-celiac gluten sensitive patients reported to have self-initiated the GFD (gluten-free diet) without dietetic supervision or education. This raises concerns for following a nutritionally adequate diet. In addition, a GFD can be more expensive than a gluten-containing diet and can be socially isolating.
In a survey of 132 patients with self-perceived non-celiac gluten sensitivity, I found two in three did not have celiac disease adequately excluded. Disease investigation prior to removal of gluten is essential to reduce the risks and complications if left untreated.
Do you think the diagnostic procedures for determining things like celiac disease are reliable? Are there any tests/procedures that are best for making an accurate diagnosis?
Investigation for celiac disease can be reliably and accurately done. With gastroscopy, you can biopsy the small bowel to assess damage. Adequate dietary gluten intake is required prior to having the gastroscopy so if gluten intake has already been removed or reduced, gluten challenges must be implemented. For example, a patient may be instructed to eat at least four slices wheat bread for a minimum four weeks. This step remains the gold standard for diagnosis.
A blood sample can also reveal raised celiac disease-associated antibodies. As with biopsies, adequate dietary gluten intake is required here as well. Although serological methods (ie. blood tests) are predictive, they alone are not sufficient for diagnosis.
Genetic testing can also reveal if someone is positive for the celiac specific genotype (HLA-DQ2 and/or -DQ8). This genotype is necessary (via a blood sample) for celiac disease. The genotype is of important screening value, given it is the only test that seems capable of excluding celiac disease for life.
Are there certain labs that are more reliable in your opinion?
Providing patients are under the guidance of a specialized gastroenterologist, diagnosis should be reliable.
Do you have any thoughts on “gluten intolerance” and how it differs from celiac disease?
For my PhD, I performed a series of three definitive experiments where the effect of gluten, free from contamination from carbohydrates, was evaluated in patients with IBS where celiac disease had been definitively excluded and who had reported benefit on a GFD.
The first study showed that gluten can trigger GI symptoms and tiredness in parallel groups and without a controlled background. Using a crossover design, the second study showed no evidence of specific or dose-dependent effects of gluten, but FODMAP restriction uniformly reduced residual symptoms. In the third study, a gluten re-challenge showed poor reproducibility of symptom induction to a specific protein. In all studies, there was no evidence for an underlying mechanism in non-celiac gluten sensitivity despite having analyzed a range of immune, inflammation and digestive markers.
Analysis of commercially available cereal grain products found rye- and wheat-derived products to contain the highest FODMAP content, predominantly fructans and GOS. The products with the lowest FODMAP contents were mostly gluten-free, based on rice, oat, quinoa and corn ingredients. It is likely, therefore, that ‘gluten restriction’ will automatically reduce a patient’s dietary FODMAP intake and this may explain why so many people report to feel better on a gluten-free diet.
What are your thoughts on preemptively avoiding gluten to avoid the development of celiac disease?
Celiac disease remains undiagnosed in the majority of patients. Accurate diagnosis ensures adequate management and support and also screening of associated complications. In European countries, celiac patients also have a subsidy to assist in the financial costs associated with the GFD.