Soy Protein Concentrate

Soy protein concentrate is soybean protein with most of the soluble sugars removed, leaving a product that is mostly protein. It is easier to digest than soybean meal, but it still contains soy isoflavones and no taurine. The Merck Veterinary Manual says plant protein sources are devoid of taurine, so cats need animal protein or added taurine. For a cat with a medical condition, ask your veterinarian.

Source: merckvetmanual.com

It raises a food's protein percentage at low cost. Soy protein concentrate is more refined than soybean meal, so it adds protein with less of the gas-forming sugar found in whole soy. In wet foods, soy proteins are also used to give chunks a meat-like texture. In dry food, its main job is to lift the crude protein number on the label.

Not on its own. The Merck Veterinary Manual says cats need taurine in the diet, have higher requirement levels for some amino acids such as arginine, and get no taurine from plant protein sources. Soy protein can supply many amino acids, but a food using it relies on meat or added taurine to meet AAFCO minimums. Pettings scores it on that basis.

Source: merckvetmanual.com

Soy does not appear among the feline food allergen sources in the Merck Veterinary Manual's table, which names beef, fish and chicken as common sources in cats and wheat, corn, dairy products and lamb as less common ones. Tufts veterinary nutritionists note that most pets with food allergies react to animal proteins. A cat can still react to any protein, and a veterinarian can confirm an allergy with an elimination diet trial.

Source: merckvetmanual.com

Pettings gives soy protein concentrate 1 out of 5 and lists it under soy. It appears on 7 of the 149 dry cat foods we list. It digests better than soybean meal, but it keeps soy's estrogen-like compounds and contains no taurine. Each food's page shows how it scores overall.