Levels of the sex hormone – which strengthens bones – drop after the menopause making women particularly vulnerable to weakening condition.
But soya could help protect bone health both before and after the menopause.
Professor Pamela Hinton, a nutritionist at Missouri University, Columbia, US, said: “The findings suggest all women might see improved bone strength by adding some soya-based whole foods to their diet.”
And the report found the food could boost younger women’s bone strength.
Prof Hinton added: “Our findings suggest women don’t even need to eat as much soya as is found in typical Asian diets.”
The findings published in the journal Bone Reports are based on female rats that have previously been shown to be a good animal model of the menopause.
Osteoporosis blights the lives of three million British women with bones becoming fragile from loss of tissue due to hormone changes or vitamin D or calcium deficiency.
It is twice as prevalent in women as men – and usually starts from the age of 50.
There is no screening programme so it goes largely undiagnosed until a bone is fractured.
A third of sufferers do not know they have it until that happens.