If you have been diagnosed with celiac disease, you have been told to follow a gluten-free diet. As you are trying to follow the diet, you will discover that gluten is a hidden ingredient in many things.
Gluten can also contaminate supposedly gluten-free foods if wheat flour is processed on the same equipment as say, rice flour. The rice flour could then have gluten in it.
How much gluten can a person with celiac disease tolerate?
There have been many studies looking at how much gluten is safe for a patient with CD. Many use a “gold standard” test, seeing what happens to actual people with CD who take in gluten, followed by intestinal biopsies to detect damage.
The gliadins in gluten have been used in some studies. They make up the half (50%) of gluten that people with CD react to. In one early study done in 1984, gliadins were given to patients with CD. 10 milligrams of gliadin did not cause a problem; 100 milligrams of gliadin were associated with minimal changes. 500 milligrams caused clear changes in the intestinal lining. 1000 milligrams caused more severe abnormalities. From this study, it appeared that between 10 and 100 milligrams of gliadin might be relatively safe. This translates into 20 to 200 mg of gluten.
A four-week challenge test in which children with CD were given daily doses of gliadin also looked at small bowel biopsy changes. 10 children got 100 milligrams a day. With this amount of gliadin, there were increased numbers of white blood cells seen on the biopsy, an early finding in CD. These children did not have symptoms. When given 500 milligrams of gliadin a day, more abnormalities were seen in biopsied tissue, and 3 of the 10 children had symptoms. This study concluded that 100 mg of gliadin (equal to 200 mg of gluten) was not safe.
A randomized trial with a larger number of participants used purified gluten, either 10 milligrams or 50 milligrams a day for a three-month period. There was at least one patient who had return of symptoms at 10 mg of gluten a day. Some had changes on biopsy at 50 milligrams of gluten a day, but others did not.
The authors of this study concluded that less than 50 mg of gluten a day is probably safe for most people with CD. This study showed that different people tolerate different amounts of gluten. While less than 10 milligrams a day would be the safest amount of gluten for patients all with CD to take in, a 50 milligram level may be more realistic.
Looking at actual dietary gluten, it is difficult to accurately measure small amounts of the substance in food. Regulatory bodies in Europe and the United States (the FDA) have suggested which tests should be used, as well as how much gluten can be allowed in so-called gluten-free food. These measurements are in ppm, which means parts per million. This kind of measurement is hard to compare to the milligrams used in research.
As an example, 100 ppm of gluten means that there can be 10 mg of gluten in 100 grams of food product. In some countries, people on gluten-free diets may eat as much as 500 grams of wheat substitutes a day. If the wheat substitutes contain 100 ppm, or 10 mg per 100 grams, anyone eating 500 grams of wheat substitute a day could get 50 mg of gluten.
As a source of reference, a standard serving of pasta is about 100 grams. At 100 ppm, there could be 10 mg of gluten in a serving of the gluten-free product. In the United States and many southern European countries, 20 ppm is the threshold that has been proposed for wheat-substitutes that can be called gluten free.
This should be low enough to keep people from eating significantly less than 50 mg per day. One serving of pasta could contain about 2 milligrams of gluten. Even eating substitute grains three times a day would probably not trigger symptoms in most people.
|ppm Gluten||Serving Size||Gluten|
|200||100 g||20 mg|
|100||100 g||10 mg|
|20||100 g||2 mg|
|10||100 g||1 mg|
If you eat a lot of truly gluten-free food, not grains or cereals with gluten removed, but pure sources of meats and vegetables and fruit, you will not be eating gluten. Once you start eating processed food, you may be eating gluten without knowing it.
If you try and keep your use of gluten-free substitutes down, you will not be eating too much gluten. If you buy gluten-free products that have been certified by the Gluten-Free Certification Organization, these have less than 10 ppm of gluten.
So, the goal is to eat as much completely gluten-free food as possibly, to buy gluten-free wheat substitutes with as little gluten as possible, and to try and remember that gluten substitutes are not truly gluten free.
Depending on the source of your substitutes and how much you eat, you could get too much gluten. How much is too much depends on the person. It may be as little as 10 mg a day for some people.
If you continue to have symptoms, you need to reevaluate what you are eating. A dietitian can help. Every person with celiac disease is different.