Whether you make equol depends on the bacteria in your gut
It is made from daidzein, one of soy's isoflavones, by gut bacteria. In the study that set the standard test, 59 percent of 29 vegetarians could and 25 percent of 12 others.
What the study found
Equol is not in soy; gut bacteria build it, and not everyone's can
It is made from daidzein, one of soy's isoflavones, by bacteria living in the gut. In the study that set the standard test for who can do this, 59 percent of 29 vegetarians could and 25 percent of 12 non-vegetarians could, which suggests diet beyond soy itself decides it.
The caveat · A quarter is three of twelve people
Twenty-five percent of twelve people is three people, so the familiar claim that a quarter to a third of Westerners are producers is consistent with this study rather than established by it. Its lasting contribution is the test, not the prevalence, and the work was done at a company that sells soy.