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Providing perspectives on recent research into vitamins and nutritionals


Non-Celiac Gluten Sensitivity and Digestive Enzymes

By Michael McBurney

A new paper evaluates the ‘healthfulness’ of gluten-free foods in Australia. A total of 3,213 packaged food products across 10 food categories were analyzed for nutritional quality using the Health Star Rating (HSR) system. The HSR system is calculated based on an algorithm factoring in nutritional quality. Unfortunately, they do not assess the food products in terms of the one attribute that often matters most - gluten exposure.

Wu and colleagues report that gluten-free products had higher HSR ratings for ice cream, corn and potato chips, and sugar-based confectionaries. The HSR ratings for gluten-free plain dry pasta were significantly lower (vs non-gluten-free). In most categories (plain dry pasta, breads, ready-to-eat breakfast cereals, cereal bars, and sweet biscuits), gluten-free products had consistently lower average protein content. In the abstract, the authors write, “The consumption of gluten-free products is unlikely to confer health benefits, unless there is clear evidence of gluten intolerance.

Gluten is the heart of the matter. Gluten is protein found in wheat, barley and rye which is very rich in the amino acid proline. Because of the unique structure of proline, intestinal enzymes often cannot cleave the bond between proline and other amino acids. This leaves large undigested residues, a 33 amino acid peptide (33-mer) derived from α-gliadin and a 25-mer peptide from γ-gliadin. These two immunogenic peptide residues bind to receptors found on the surface of pro-inflammatory T cells in the lamin propria of the small intestine. The 33- and 25-mer peptides derived from gluten are the primary initiators of celiac disease and non-celiac gluten sensitivity.

Notwithstanding the benefits of gluten in baking, nutritional ratings of food products may seem irrelevant if one is sensitive to gluten. It is the gluten content of these foods that is of primary importance. In the absence of celiac disease, 7.3% of Australians report adverse physiological effects, predominantly gastrointestinal, associated with wheat consumption. In short, they want to avoid consuming gluten. The prevalence of celiac disease varies geographically and is increasing in many regions, including Asian countries.

People are looking for gluten-free products. Gluten is one of the most commonly searched terms on the internet. Despite the 2013 FDA ruling on ‘gluten-free’ food labeling, consumers may still be exposed to low levels of gluten (20 parts per million of gluten).

Of several commercially available digestive enzyme supplements, only one using a prolyl endopeptidase enzyme from Aspergillus niger degrades immunogenic gluten epitopes. The prolyl endoprotease seems to be a promising option to degrade inadvertent dietary gluten.   

Main Citation

Wu JHY, Trevena H, Crino M, Stuart-Smith W, Faulkner-Hogg K, Louie JCY, Dunford E. Are gluten-free foods healthier than non-gluten-free foods? An evaluation of supermarket products in Australia. 2015 Br J Nutr doi: 10.1017/S0007114515002056

Other Citations

Golley S, Corsini N, Topping D, Morell M, Mohr P. Motivations for avoiding wheat consumption in Australi: results for a population survey. 2014 Publ Health Nutr doi: 10.1017/S136898000652

Catassi C, Gatti S, Fasano A. The new epidemiology of celiac disease. 2014 J Ped Gastroenterol Nutr doi: 10.1097/01.mpg.0000450393.23156.59

Kabbani TA, Vanga RR, Leffler DA, Villafuerte-Galvez J, Pallav K, Hansen J, Mukherjee R, Dennis M, Kelly CP. Celiac disease or non-celiac gluten sensitivity? An approach to clinical differential diagnosis. 2014 Am J Gastroenterol doi: 10.1038/ajg.2014.41

Janssen G, Christis C, Kooy-Winkelaar Y, Edens L, Smith D, van Veelen P, Koning F. Ineffective degradation of immunogenic gluten epitopes by currently available digestive enzyme supplements. 2015 PloSONE doi: 10.1371/journal.pone.0128065

Salden BN, Monserrat V, Troost FJ, Bruins MJ, Edens L, Bartholome R, Haenen GR, Winkens B, Koning F, Masclee AA. Randomised clinical trial: Aspergillus niger-derived enzyme digests gluten in the stomach of healthy volunteers. 2015 Aliment Pharmacol Therapeut doi: 10.1111/apt.13266