A question people who know about celiac disease frequently ask is, “Why is the incidence of this condition increasing?” It was once considered a rare disease, but now it appears that around 1% of the people in many parts of the world have CD. Part of the increase may be due to improved diagnosis. But there are certainly more people coming down with celiac disease than in the past.
Some have suggested that people are eating more gluten than they used to. This could be because they are eating more products made with wheat, like bread and pasta, or because today’s wheat has more gluten.
An agricultural expert named Donald D. Kasarda recently discussed these ideas in a paper published in the Journal of Agricultural and Food Chemistry. In his opinion, eating greater amounts of gluten in the wheat used to make things liked baked goods and pasta is not necessarily responsible for the increase in CD.
Kasarda used all the information he could gather to estimate the amount of gluten in various wheats as well as the amount of wheat consumed per person over the years. Keep in mind that proteins were not “discovered” until some 250 years ago, and gluten is a protein. There is no actual data available for every piece of the puzzle.
Ways to at least indirectly measure the protein content of foods were developed in 1883, and how to best do this continued to undergo debate and experimentation. Not until the late 20th century was there a way to measure gluten. 70% to 75% of the protein in wheat is gluten.
In the very distant past, wild wheat most likely had higher protein content, which can be measured if these strains are grown now. The grains of these wheat’s were small, and as farmers domesticated wheat, they selected larger grains which had less protein.
As wheat was bred over the years, grains of more genetic complexity were developed. Farmers were looking at practical concerns like the yield of grain, and suitability for bread making. When making bread, wheat with more protein (and therefore gluten) is desirable. When baking pastries and cakes, wheat with less protein gives a better result. So-called “all-purpose flour” is not best for everything but can be used for most foods needing wheat.
The exact protein content of wheat from the first half of the 20th century is not known, because it depended on type of wheat as well as growing conditions and geography. The average ranged from a low near 12% to a high of almost 19%, with most falling in the middle. The relationship between celiac disease and gluten was not understood at all until 1950, and not generally accepted until even later. When given the choice, most bakers picked the wheat with higher protein content.
As a group, Americans ate more wheat in 1900 than 1970. Between 1970 and 2000, consumption rose slowly, but then started to go down again. Wheat consumption now is much less than in 1900, but higher than it was in 1970.
Kasarda made a number of reasonable assumptions to estimate gluten consumption during these years. He does not believe that there was a definite increase in the gluten content of wheat that coincided with the increase in celiac disease, although there was an increase in wheat consumption during some of the time.
He is also concerned about what is called “vital gluten.” When starch granules from wheat dough are washed, they yield vital gluten. Vital gluten is added to many foods to improve various qualities. For example, whole grain bread may have vital gluten added to increase its volume. Kasarda estimates that people are now getting 3 times as much vital gluten as they did in 1977. This coincides with the increase in celiac disease.
Between the increase in wheat eaten in the second half of the 20th century and the addition of vital gluten, people may be getting more gluten in their diet than at times in the past. There is no way to be certain of this. For example, people ate a lot of wheat in the 1930’s, and for some unknown reason that may have been environmental, the protein content of wheat in 1938 was an extremely high 18.78%. There may have been other periods when more gluten was actually consumed.
No one actually knows what turns on the celiac disease “switch.” People with CD on a gluten-free diet can have symptoms after eating as little as 50 to 100 mg of gluten. The average piece of wheat bread has 1.8 grams of gluten (1,800 mg).
Perhaps all these factors have led to average diets with more gluten than in the past, and that has triggered celiac disease in people with the genetic tendency to have it. More research is needed and is being done. Researchers are especially interested in finding wheat with less gluten and types of gluten that are less toxic for people with celiac disease.