By Reed Mangels, PhD, RD
VRG often gets questions about the oxalate content of vegan foods. Some people limit their dietary oxalate intake because of conditions such as kidney stones, fibromyalgia, and interstitial cystitis. There are a number of resources for people interested in knowing more about the amount of oxalate in different foods. We pointed out some in this blog post from 2011: http://www.vrg.org/blog/2011/05/30/oxalic-acid/. Jack Norris, RD, a vegan dietitian, frequently writes about oxalates on his blog. One of his posts led us to a list of tables developed by the Harvard School of Public Health, which list the oxalate content of many foods. Even with all of these resources, we were stumped when we received a question from a reader about the amount of oxalate in seitan.
We contacted Michael Liebman, PhD, a professor at the University of Wyoming, who has done research on the oxalate content of foods. He agreed to analyze a sample of gluten flour which is used to make seitan. Dr. Liebman found that 100 grams of Arrowhead Mills Vital Wheat Gluten had 54 mg of total oxalate and 15.1 mg of soluble oxalate. Soluble oxalate appears to be more easily absorbed. Dr. Liebman concluded that a tablespoon of Vital Wheat Gluten (which weighs 9 grams) has 4.9 mg of total oxalate.
We took these numbers and used a recipe for seitan from Vegetarian Journal. According to this recipe, 2 cups of gluten flour yields 5 or 6 servings (4 ounces) of seitan. The gluten flour would contribute 26-31 mg of oxalate to a 4 ounce serving of seitan. The total oxalate in the seitan would be somewhat higher depending on the other ingredients which were used. Other ingredients in the seitan recipe were not included in the calculation. These ingredients include garlic powder, ground ginger, water or vegetable stock, lite tamari, Braggs liquid amino acids, or soy sauce, and optional sesame oil. The broth to cook the seitan contains tamari or soy sauce, kombu (a type of seaweed), and optional ginger. We are uncertain as to how much oxalate from the broth ingredients is present in the seitan and if some oxalate from the seitan is lost into the cooking broth so our estimate of the oxalate content of the seitan is just that, an estimate. Ginger, garlic, and soy sauce have all been identified as low in oxalates in one or more databases.
The contents of this blog, website, and our other publications, including Vegetarian Journal, are not intended to provide personal medical advice. Medical advice should be obtained from a qualified health professional. We often depend on product and ingredient information from company statements. It is impossible to be 100% sure about a statement, info can change, people have different views, and mistakes can be made. Please use your best judgment about whether a product is suitable for you. To be sure, do further research or confirmation on your own.