1 interaction related to fermented soy
Tempeh is a fermented soybean cake rich in soy protein, and soy protein binds levothyroxine in the gut and reduces how much of the thyroid hormone is absorbed. Fermentation lowers isoflavone bioavailability but leaves the soy protein intact, so the absorption interference remains. Taken consistently close to the dose, this can lower thyroid hormone levels enough to push TSH out of its target range.
