1 interaction related to fermented soy
Tempeh is a fermented soybean cake, and soy protein binds levothyroxine in the gut and reduces its absorption, with documented decreases of 16 percent at 20 grams of soy protein and over 35 percent at 40 grams. Fermentation reduces isoflavone bioavailability but leaves intact soy protein that still interferes with thyroid hormone uptake.