Premenopausal women whose diet is high in isoflavone-rich soy products have a 30% lower risk of developing an invasive breast tumor compared to those with a very low intake, scientists from Roswell Park Cancer Institute explained at the 9th Annual American Association for Cancer Research (AACR) Frontiers in Cancer Prevention Research Conference.

Isoflavones belong to a class of usually naturally-occurring organic compounds that are related to the isoflavonoids. Many isoflavones act as phystoestrogens – nonsteroidal plant compounds that have estrogenic effects – in humans and other mammals. Isoflavones are antioxidants. They have been found to have cancer fighting qualities in several studies. Isoflavones can be found almost exclusively in the bean (Fabaceae/Leguminosae) family.

Researcher Anne Weaver, said:

This study was unique in that we looked at specific subtypes of breast cancer, and found a suggestion that menopausal status may play a role in risk.

Weaver and team compared data on 611 healthy females and 683 diagnosed with breast cancer. They gathered information on their eating habits via a food frequency questionnaire which measured isoflavones dietary (not supplemental) intake. They divided isoflavones ingestion into three groups.

The team discovered that the women who consumed the most isoflavones were about 30% less likely to develop an invasive breast tumor than those with very low consumption. The high isoflavones intake women also had a 60% lower risk of developing a Grade 1 tumor.

The scientists made the following observations related just to premenopausal women:

  • A 30% lower risk of Stage 1 disease among the highest isoflavone consumers
  • A 70% lower risk of developing a tumor bigger than 2cm among the highest isoflavone consumers
  • A 60% lower risk of developing Stage 2 breast cancer among the highest isoflavone consumers

The lower risks listed above were only observed among the premenopausal women; not the postmenopausal ones.

Weaver and team stressed that further studies and confirmation are needed and that their findings are not authoritative.

Source: American Association for Cancer Research

Written by Christian Nordqvist