Hominy looks like corn that got puffed up and softened, and in a way, that’s exactly what it is. But the process behind it is one of the most clever pieces of food science humans ever came up with, and it was worked out in Mesoamerica long before modern science explained to us all what a vitamin is.

What is nixtamalization?

The word comes from Nahuatl, the language of the Aztecs: nextli (ashes) and tamalli (corn dough). It describes the alkaline cooking of corn, a process that originated in Mesoamerica.

Dried corn is cooked in water with lime (or, traditionally, wood ash), then left to soak. This lime is a white mineral powder, calcium hydroxide, sold as pickling lime or, in Mexican grocery stores, as cal. According to food scientists at the University of Nebraska–Lincoln, the alkaline solution breaks down and removes the pericarp (the tough outer skin), softens the inside of the kernel, and lets water and calcium move into the starchy center.

The treated corn is called nixtamal. Leave the kernels whole and you have hominy, the star of pozole. Grind them and you get masa, the dough behind tortillas, tamales, and pupusas.

Why it matters: what nixtamalization does to corn

It unlocks niacin

Corn contains niacin (vitamin B3), but much of it is bound up with carbohydrates and small proteins in a form your body has a hard time absorbing. As a medical review on niacin deficiency puts it, Indigenous peoples across the Americas ate corn treated with lime or wood ashes, which increased the bioavailability of its niacin.

That mattered enormously when corn traveled without the process. In the early 1900s, pellagra, the disease caused by niacin deficiency, was widespread in the Southern United States among people who depended heavily on corn. Same crop, different preparation, very different outcome.

Here’s the part I find fascinating: scientists have actually debated why it works. The UN Food and Agriculture Organization’s review of maize in human nutrition describes two camps: one points to the release of bound niacin, the other to a better balance of amino acids, which lowers how much niacin the body needs. The answer may well be a bit of both.

It adds calcium

Because the corn soaks in calcium hydroxide, it absorbs calcium. According to the FAO, the calcium content of tortillas can increase by up to about 400 percent compared with the original corn, and studies found that calcium to be highly bioavailable.

How much calcium ends up in the final food varies. A cup of canned hominy, for example, has only about 17 mg.

It lowers phytic acid

Phytic acid is what’s known as an antinutrient: a natural compound in grains and seeds that binds to minerals like iron and zinc and makes them harder to absorb. Nixtamalization reduces phytic acid levels, which can leave more of those minerals available.

It changes how corn’s protein behaves

Nixtamalization doesn’t add protein to corn, but it changes how available the protein that’s there is. In lab digestion tests summarized by the FAO, enzymes released twice as much digested protein from tortillas as from raw corn in the first stage of digestion, and essential amino acids, including lysine and tryptophan, came out at higher levels, suggesting a faster release from the proteins. Overall, the FAO reports that protein quality is “slightly but consistently better” in tortillas than in raw corn.

The process matters, though. One study found that very long soaking times reduced lysine and tryptophan, two amino acids corn is already short on, and lowered protein digestibility. Like a lot of cooking, it’s about doing it right, not just doing it.

A bonus: it can reduce mycotoxins

Corn can be contaminated with mycotoxins, toxic compounds produced by molds. Research from the University of Nebraska–Lincoln shows nixtamalization can reduce aflatoxins and fumonisins, though how much varies with the process.

Your corn tortillas go through the same process

Traditional corn tortillas are made from masa, which is ground nixtamal. Masa harina, the corn flour used to make tortillas at home, is dried and ground nixtamalized corn. So the corn tortillas in my chicken enchilada casserole and my free 3-day meal plan are getting the same treatment as hominy, just in a different shape.

Want to check your own? Look at the ingredient list. Nixtamalized corn is often listed as “corn treated with lime,” “nixtamal,” or with lime or calcium hydroxide as an ingredient.

Is hominy low-carb?

Not on its own. One cup of canned white hominy has about 24 grams of total carbs, with about 4 grams of fiber and 2 grams of protein. That’s not a free food, but it’s not off-limits either. A smaller portion in a brothy soup or stew fits comfortably in a low-carb day, the same way I use a little potato or rice when it’s what makes the dish.

FAQ – Frequently Asked Questions