Reading labels when you avoid gluten

Most of this site is about words on packaging that mean nothing. This is the exception, and it is worth appreciating.

Under 21 CFR 101.91, a food labelled “gluten-free” in the US must contain less than 20 parts per million of gluten. The rule names exactly three gluten-containing grains: wheat, rye and barley. It is a threshold, it is testable, and a manufacturer using the phrase has to meet it.

So when you see that claim, you are being told something specific by someone who can be held to it. Treat it as the strongest signal on the package, stronger than the ingredient list.

Two different conditions, one word

Worth separating early, because the labelling systems treat them differently and that difference causes most of the confusion below.

Coeliac disease is an immune reaction to gluten, the protein in wheat, rye and barley. It is managed by keeping total gluten intake below a threshold, which is why parts per million matter.

Wheat allergy is an allergic response to wheat proteins specifically. Rye and barley are not necessarily involved. Allergen labelling covers wheat, because wheat is one of the nine major US allergens.

If you have coeliac disease, the gluten-free claim is the thing to look for. If you have a wheat allergy, allergen labelling is doing more work for you, and rye and barley may not be your concern at all.

The gap: barley has no allergen warning

This is the single most useful thing on this page.

Wheat is a major allergen, so it gets declared prominently. Barley is a gluten-containing grain but is not a major US allergen, so it gets no bold “Contains” statement.

The practical result is Barley malt extract, sitting quietly in the middle of a breakfast cereal’s ingredient list with nothing to draw your eye. Two regulations written for two different problems, meeting at an awkward angle. If you see the word “malt” in a food and you are avoiding gluten, assume barley.

The reassuring one

Modified food starch worries people and mostly should not. It can be made from corn, potato, tapioca or wheat, and in the US it is usually corn. If it is made from wheat, allergen rules require wheat to be declared, so a US label that says only “modified food starch” is not telling you about a wheat product.

And “modified” here means physically or chemically treated so the starch thickens properly. It has nothing to do with genetic modification, which is a separate thing under a separate name.

The one that is not food

Hydrolysed wheat protein is wheat, and it appears in shampoos and soaps as often as in food. For coeliac disease this is generally less of a concern than swallowed gluten, since coeliac is a reaction to gluten that is eaten. For wheat allergy the picture is different, and the reason is genuinely remarkable: a specific hydrolysed wheat protein in a Japanese facial soap sensitised more than two thousand people through the skin, who then reacted to eating wheat.

That is worth reading in full, and it is the reason we treat the bathroom and the kitchen as one problem.

The habit

Look for the gluten-free claim first, because it is the only thing on the package that carries a number behind it. If it is not there, read the list for wheat, rye, barley and malt. And re-read products you already trust when the packaging changes, since a redesign often travels with a reformulation.

The general mechanics are in how to read an ingredient label.