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Are There Really Different Types of Wheat With ‘Safe’ Gluten?

Stormy

Doctors hear stories about people with celiac disease who can tolerate wheat some of the time depending on where they are. For example, one woman can eat a croissant in Paris or pasta in Italy without symptoms. But any gluten-containing food in the United States makes her sick immediately. This type of story is considered anecdotal, and while there may be many other people with similar stories, they do not prove anything from a scientific standpoint.

Is there something different about wheat from different parts of the world? Is there something different between modern wheat and ancient wheat? Have wheat-growing practices over the centuries or more modern techniques changed the properties of gluten in wheat and other grains? If there are less problematic varieties of wheat, and they can be identified, it could lead to designer wheat or a known available wheat that could be tolerated by patients with CD.

While work is active in this area, unfortunately so far, wheat containing “good” gluten has not been found.

Gluten is the name for the proteins in wheat including gliadins and glutenins. All of the gluten proteins, especially what are called α-gliadins, cause reactions in people with CD. Proteins are made of amino acids. Gluten proteins, especially α-gliadins contain a lot of the amino acids glutamine and proline. These two amino acids are sticky, and that is part of what makes the consistency of bread and other products made from wheat. However, glutamine is thought also to be responsible for the way gluten causes problems for people with celiac disease.

In the intestine, an enzyme called tissue transglutaminase (tTG) converts the glutamine into glutamic acid. The pieces of gliadin that have been changed in this way bind to certain receptors in people predisposed to have celiac disease. This leads to a long chain of biologic and chemical processes that ultimately turn into the signs and symptoms of the disease.

Researchers have determined the amino acid sequences of the gliadins and glutenins thought to be problematic. This has been a big job, and a lot has been learned about which pieces are the most toxic as well as how to test grains for them. What is called an ELISA (Enzyme-Linked Immunosorbent Assay) can be used to sample gliadins to find certain pieces known to be what is called immunogenic.

A recently-published study from Italy investigated ancient strains of grain that some people hope might be less toxic for people with CD than modern wheat. The potential for inducing celiac disease based on the content of the ancient durum wheats Graziella Ra and Kamut was analyzed. The α-gliadins in these two ancient wheats were compared to more contemporary durum wheat, including Cappelli (a traditional Italian wheat), as well as modern varieties Flaminio, Grazia and Svevo.

There is some difference of opinion among scientists studying wheat as to the exact name or derivation of some of these wheats. However, most agree that Kamut is derived from an ancient relative of what is now called T. durum. Graziella Ra is a similar to Kamut, was brought to Italy in the 1970’s, and then not used for a long time, having recently been “rediscovered.” Capelli was the first durum wheat selected for cultivation in the past, whereas Grazia and Flaminio are modern and used now for making most bread and pasta in Italy. There is no question that these wheat varieties have different properties in terms of growth, yield, nutritional content, and appearance. What is not known is how they might differ in relation to patients with celiac disease.

The study analyzed these wheat varieties thoroughly. The older wheats had even more of the α-gliadins thought to trigger reactions in patients with celiac disease than the newer wheats. This made sense to the investigators, because the older wheats were thought to be higher in protein. More protein means that the wheat is higher in glutenins and gliadins. While some of the gliadins in older wheat have different amino acid sequences, they seem to still be able to stimulate the cells that start the reactions of celiac disease.

The researchers doing the study do believe further research should be undertaken to look at the different amino acid sequences of certain gliadins because some of them may be less stimulatory. However, the total content of all gliadins and glutenins in the wheat varieties and the fact that there are more in the older wheat and not less, led them to the belief that the ancient wheat grains are definitely not safer for people with celiac disease. This was their conclusion:

“Therefore, we suggest that Graziella Ra and Kamut are potentially as toxic as modern wheats with reference to CD and strongly recommend that they should not be introduced in the diet of celiac patients.”

The techniques used to analyze these wheat varieties can be used on different kinds of wheat as well as other grains. There may be grains that do have less stimulatory gliadins. It is also possible that techniques will be developed to engineer wheat with less of these proteins or medication discovered to inactivate them. At the current time, though, people with celiac disease need to continue to consider all wheat as off the gluten-free diet.

References:
Colomba M.S., Gregorini A. Are Ancient Durum Wheats Less Toxic to Celiac Patients? A Study of α-Gliadin from Graziella Ra and Kamut. The Scientific World Journal. Volume 2012, Article ID 837416, 8 pages
Van Herpen T. W., Goryunova S.V., van der Schoot J., et al. Alpha-gliadin genes from the A, B, and D genomes of wheat contain different sets of celiac disease epitopes. BMC Genomics 2006, 7:1-13.
Morón B., Cebolla Á., Manyani H., et al. Sensitive detection of cereal fractions that are toxic to celiac disease patients by using monoclonal antibodies to a main immunogenic wheat peptide.  American Journal of Clinical Nutrition 2008; 87: 405–14.
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