If you have read about the definitions of “gluten-free” proposed by both the Food and Drug Administration and the Codex Alimentarius Commission you may be wondering just how much gluten is in a product containing 20 parts per million gluten…

The proportion 20 parts per million is the same as .002%. This is also the same as 20 milligrams of gluten per 1 kilogram of food or 20 milligrams of gluten per 35.27 ounces of food. To put this amount into context, a 1-ounce (28.35 grams) slice of gluten-free bread containing 20 parts per million gluten would contain 0.57 milligrams of gluten.

You also may be wondering how much gluten might be eaten each day if grain foods (bread, pasta, breakfast cereal) contained 20 parts per million gluten (rememeber, under FDA’s proposed rule, gluten-free foods must contain less than 20 parts per million gluten. This is a maximum amount and many products are likely to contain less than this amount).

If you require 1,800 to 2,000 calories a day you should eat 6 1-ounce grain equivalents each day. Six ounces of grain food containing 20 ppm gluten would contain 3.42 milligrams of gluten.

If you require 2,200 calories a day you should eat 7 1-ounce grain equivalents each day. Seven ounces of grain food containing 20 ppm gluten would contain 3.99 milligrams of gluten.

If you require 2,400 calories a day you should eat 8 1-ounce grain equivalents each day. Eight ounces of grain food containing 20 ppm gluten would contain 4.56 milligrams of gluten.

If you require 2,800 to 3,200 calories a day you should eat 10 1-ounce grain equivalents each day. Ten ounces of grain foods containing 20 ppm gluten would contain 5.70 milligrams of gluten.

So now you might be wondering whether eating 3 to 6 milligrams of gluten daily is safe. In 2007 Catassi and colleagues assessed the effects of consuming capsules containing 0, 10, and 50 milligrams of gluten on the intestinal morphology of persons with celiac disease who reportedly were compliant with a gluten-free diet (Am J Clin Nutr 2007;85:160-166). During the study participants maintained a strict gluten-free diet  and were only allowed to consume specially marked gluten-free cereal foods containing less than 20 parts per million gluten. Gluten intake from the diet was estimated to be less than 5 milligrams. Researchers found a significant decrease in the villous height to crypt depth ratio in the group taking the 50 milligram capsule. No significant change was found in the vh/cd ratio in the group taking the 10 milligram capsule.

What this means

Even if all of the gluten-free grain foods you ate contained 20 parts per million gluten (and they probably won’t) you would have to eat a lot more than the recommended number of servings to approach an intake of 10 milligrams of gluten.

For more information on the definitions of “gluten-free” proposed by both the Food and Drug Administration and the Codex Alimentarius Commission go to the Newletter home page at www.glutenfreedietitian.com and click on “Codex standard for gluten-free foods” and “FDA gluten-free labeling.”