A new study carried out in Milan (see abstract below) is suggesting that some of the proteins in maize/corn contain amino acid sequences which resemble wheat/gluten so closely that eating maize or corn could have a similarly damaging effect on some coeliacs as eating wheat.
If this is correct it could have a very significant effect on the diets of those on gluten-free diets and on the gluten-free/freefrom food industry as maize/corn is one of the ingredients most widely used as a wheat alternative in gluten-free foods for coeliacs.
Plant Foods Hum Nutr. 2012 Feb 2. [Epub ahead of print]
Maize Prolamins Resistant to Peptic-tryptic Digestion Maintain Immune-recognition by IgA from Some Celiac Disease Patients.
Cabrera-Chávez F, Iametti S, Miriani M, de la Barca AM, Mamone G, Bonomi F.
Source
Dipartimento di Scienze Molecolari Agroalimentari, Università degli Studi di Milano, Milano, Italy.
Abstract
Maize is used as an alternative to wheat to elaborate foodstuffs for celiac patients in a gluten-free diet. However, some maize prolamins (zeins) contain amino acid sequences that resemble the wheat gluten immunodominant peptides and their integrity after gastrointestinal proteolysis is unknown. In this study, the celiac IgA-immunoreactivity to zeins from raw or nixtamalized grains, before and after peptic/tryptic digestion was evaluated and their possible immunogenicity was investigated by in silico methods. IgA from some celiac patients with HLA-DQ2 or DQ8 haplotypes recognized two alpha-zeins even after peptic/tryptic proteolysis. However, digestion affected zeins after denaturation, reduction, and alkylation, used for identification of prolamins as alpha-zein A20 and A30 by MS/MS sequencing. An in silico analysis indicated that other zeins contain similar sequences, or sequences that may bind even better to the HLA-DQ2/DQ8 molecules compared to the already identified ones. Results concur to indicate that relative abundance of these zeins, along with factors affecting their resistance to proteolysis, may be of paramount clinical relevance, and the use of maize in the formulation and preparation of gluten-free foods must be reevaluated in some cases of celiac disease.
PMID: 22298027 [PubMed - as supplied by publisher]
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