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Are botanical estrogens safe?

“Nutritional supplements represent a $50 billion per year industry – one that’s not tightly regulated,” says Russ Turner, professor and director of the OSU Skeletal Biology Research Laboratory.

He and colleague Urszula Iwaniec are conducting research that will add to the body of knowledge about botanical estrogens found in many supplements. “We want to know if the benefits exceed the risks of taking botanical estrogens as supplements – who may benefit and who may be at risk when taking these supplements and what adverse side effects may exist,” Russ explains. “In the end, we hope to determine whether botanical estrogens represent a safe alternative to traditional hormone therapy.”

botanical supplements

Many women take plant-based estrogens that are advertised as natural, presuming they are safer than hormone replacement therapy.

“Manufacturers claim that supplements with botanical estrogens slow bone loss for postmenopausal women, lower the incidence of breast cancer, reduce hot flashes, and improve mental function,” says Urszula, whose research focuses on breast cancer metastases to bone. But these supplements also have the potential to mimic the detrimental actions of natural estrogens – those we produce ourselves – that can stimulate the growth of tissues that put us at risk of breast cancer, she explains.

Botanical estrogens are found in soy, dong quai, and wild yam. “In supplements, although they may be the same compound, they are processed – concentrated, purified, or extracted and sometimes chemically modified – and this is where the risk comes in,” Russ adds. “The impact of these processed botanical estrogens hasn’t been sufficiently tested.”

Russ and Urszula are collaborating with colleagues at the University of Illinois Botanical Research Center and the University of Mississippi on this project, funded by an $8 million, five-year grant from the National Institutes of Health. Together, they are investigating the impact of botanicals on bone health, breast cancer growth and metastasis, and cognitive function.