Seitan – A High Lysine Food
Awhile back, a reader sent me a copy of a 2009 paper that analyzed the amino acid amounts in wheat gluten protein (1).
The USDA nutrient database does not give amino acid amounts for wheat gluten and it doesn’t include seitan at all. I have long suspected that seitan would be a good source of the amino acid lysine (which is generally the limiting amino acid in vegan diets), but I had no way to verify this until getting the 2009 paper.
Upon doing some calculations I estimate that White Wave seitan has approximately 656 mg of lysine per serving, making it one of the highest sources of lysine among plant foods. I have added this information to Table 3 of Protein at VeganHealth.org. You can see more details about how I came up with this amount in the footnotes of the table, if interested.
There is one disconcerting thing about the 2009 paper – it has no amounts for tryptophan and no explanation as to why. And if you add up the amounts of the other amino acids in mg/g of protein, it comes to almost exactly 1 g, leaving no room for tryptophan. I have written the authors to find out why this might be.
The paper is rather technical and not being a laboratory scientist, I didn’t even understand most of it. If any readers would like to take a look at it, let me know through the contact form.
In any case, I feel confident now that seitan is a good source of lysine and I have added it to my protein recommendations as an option for getting your daily amount of lysine.
Addendum of November 7, 2012:
I have communicated with one of the paper’s authors, Dr. Ine Rombouts who told me that the protein in wheat is 80% gluten and that gluten is very low in tryptophan – that it only has negligible amounts. The other 20% of wheat protein is made up of albumins and globulins which have more tryptophan. This is why wheat has tryphtophan but wheat gluten does not.
1. Rombouts I, Lamberts L, Celus I, Lagrain B, Brijs K, Delcour JA. Wheat gluten amino acid composition analysis by high-performance anion-exchange chromatography with integrated pulsed amperometric detection. J Chromatogr A. 2009 Jul 17;1216(29):5557-62. Epub 2009 Jun 3. | link