Does Rye Bread Have Gluten?

Although I am not personally gluten sensitive beyond the normal sensitivity of all humans to gluten, a storage protein in the Triticeae grasses family, to which wheat and rye cereal grains belong, I do my best to avoid foods, containing these proteins.

I’ve operated a dedicated gluten-free bakery for 3 years. During that time, of course, I met and conversed with a lot of people, who suffered from gluten sensitivity. What is interesting, and what I wanted to discuss in this installment, is what some of them told me back then that they were fine, or at least they had milder reactions when consuming rye foods and breads. And, that’s despite the fact that most of them were highly sensitive to gluten.

As I said in the beginning both wheat and rye belong to the same botanical family and they both have the type of storage proteins that elicit allergic or auto-immune reactions in roughly 8 percent of the population.

So, let’s see what it is with rye foods and breads and whether they are safe for those, who should avoid gluten.

The storage proteins in the cereals from the triticeae family are called prolamins (there are other proteins in these grains, called “functional proteins”, but they don’t cause problems in gluten-sensitive people).

In wheat the problem-causing protein is known as gluten*and in rye – secalin (hordein in barley). Both of them contain a protein fraction, called gliadin, and precisely this is the fraction that’s the trouble maker in gluten-sensitive individuals.

There are several types of gliadins. The type of gliadin, affecting gluten-sensitive (and celiac) individuals to the greatest degree is a form of alpha-gliadin – a 33 amino acids-long fraction (33-mer gliadin). This fraction is not completely digested neither by stomach and pancreatic proteases nor by the enzymes in the upper small intestine (brush-border membrane enzymes).

It looks like from what we’ve found so far we can confidently conclude that rye foods, and of course rye breads, are not safe for people with gluten sensitivities. So, how come some of them still report better tolerance of these foods when compared to pure wheat containing foods and breads?

The answer (or at least partially) may be sought in the following:

  • as opposed to gliadin and glutenin in wheat, rye storage proteins do not form gluten when mixed with water and kneaded (keep in mind they still contain gliadin, which is what’s causing the problem in most people). Gluten provides one extra step for the digestive process of breaking down the gliadin fraction to smaller peptides
  • rye flour contains lower levels of prolamins and glutelins (gliadin-containing proteins) than wheat flour **
In conclusion, rye flour and foods are not safe for gluten-intolerant and celiac individuals. However, some less-sensitive people may be able to tolerate pure rye foods and rye breads better than other people with similar conditions due to the fact that there is less gliadin in rye when compared to wheat. Still, more and more evidence is coming out, demonstrating the ill-causing effects of the storage proteins in rye (1, 2).
If I personally had a well-pronounced gluten (gliadin) sensitivity in any form, I’d refrain from using any cereal grains from the triticeae family of grasses, including rye.

* Gluten actually forms only when wheat flour is mixed in water and the two proteins – glutenin and gliadin – form a complex network by associating via strong disulphide bonds. Before flour is mixed with water and kneaded these two proteins coexist separate from each other and not in the form of what’s known as gluten in bread making and other industries.

** Resource: “Food Biochemistry and Food Processing” By Benjamin K. Simpson

One Response

  1. Dear Ivan, thank you so much for your very detailed, professional explanation. We run a little, family bakery on The Samui Island, and bake a 100% rye sourdough bread. Some people came up with the info, that Rye flour doesn’t content any gluten, and I wasn’t sure…After reading your article, all came very clear. So, thank you again. I’ll be happy to share your article at my facebook page, too.

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