Superbrewed Food Postbiotic Cultured Protein Exhibits Effective Muscle-Building Response: Study

Superbrewed Food recently presented new clinical findings on its postbiotic cultured protein SB1 at Nutrition 2026, the annual meeting of the American Society for Nutrition (ASN).

The study, conducted by Nicolaas E.P. Deutz, MD, PhD, director of the Center for Translational Research in Aging and Longevity at Texas A&M University, was a randomized, single-blind, placebo-controlled crossover study and the first of its kind to directly compare postbiotic cultured protein against whey protein and pea protein isolates. The study used a novel stable isotope pulse technique that measured amino acid bioavailability and the intracellular anabolic response to a meal.

Postbiotic cultured protein performed comparably to whey, and either matched or outperformed pea protein, the most widely used plant-based alternative.

Net intracellular protein synthesis, expressed as a percentage of ingested protein, was 65% for whey, 47% for pea, and 53% for postbiotic cultured protein. All three proteins had a bioavailability of approximately 75%.

Lysine was a common limiting factor across all three sources. Intracellular utilization of lysine was statistically comparable across all three proteins, making it the key limiting amino acid regardless of source. The comparable shortfalls in lysine and methionine relative to intracellular demand required the body to draw on its own amino acid reserves to compensate, regardless of protein source.

Utilization data showed that fewer essential amino acids would need to be added to the postbiotic cultured protein than pea protein to optimize quality.

“This stable isotope pulse method lets us measure not just how much protein-derived amino acids appear in the blood after a meal, but how efficiently the body actually uses those amino acids inside the cell to build new protein,” said Deutz. “What stood out is that postbiotic cultured protein performed on par with whey protein, and that lysine emerged as the limiting amino acid across all three sources, even whey. That tells us protein quality can’t be assumed from a label; it has to be measured directly, and postbiotic protein measured up.”

“For years, the alternative protein industry has asked consumers to trade nutrition for sustainability. This independent study, conducted by one of the most rigorous protein metabolism research labs in the world, shows that trade-off doesn’t have to exist,” said Bryan Tracy, PhD, CEO and co-founder of Superbrewed Food. “Postbiotic cultured protein delivered an anabolic response and bioavailability on par with whey and a stronger amino acid foundation than pea protein, all from a non-GMO, zero-lactose, allergen-free ingredient made through fermentation, the same natural process used to brew beer and culture yogurt. This is the kind of independent, peer-reviewed evidence our industry needs to move fermentation-derived protein from promising to proven.”