Past about 60 mg of isoflavones a day, the benefit stops growing
In pooled observational data on breast cancer survivors, recurrence risk fell as soy isoflavone intake rose, reaching about 30 percent lower at that point and no lower past it.
What the study found
The benefit stops climbing at about 60 mg of isoflavones a day
Pooled observational data on breast cancer survivors show recurrence risk falling as soy isoflavone intake rises, reaching about a 30 percent reduction at that point and no lower past it. The curve's departure from a straight line cleared significance, so the plateau is a measured shape.
The caveat · The curve bends for recurrence only
The shape comes from observational data, so it maps an association rather than a demonstrated causal curve. Nonlinearity cleared significance for recurrence only; for breast-cancer death and death from any cause it did not, and most of the reduction there sat between 20 and 40 mg a day.