Soy linked to breast cancer survival
Evidence hints tofu might be good for you.
Taken at first blush, it sounds like pseudoscience: soy can treat breast cancer.
While the science is still far from settled, there is growing of evidence of a correlation between soy intake and breast cancer survival. This is remarkable because oestrogen-mimicking isoflavones in soy products were once considered cancer risk factors.
The most recent findings, published in the journal Cancer, come from a team led by Fang Fang Zhang of Tufts University in Massachusetts. The team set out to resolve the apparent contradiction between laboratory and epidemiological studies that found a link between higher isoflavone intake and reduced mortality, and other research that suggested the same compounds might reduce the effectiveness of hormone therapies.
Soy represents by far the largest source of isoflavones in the human diet.
The researchers studied the diets of 6,235 American and Canadian women with breast cancer. Over nine years, the women who consumed large amounts of isoflavone had a 21% lower risk of dying than those who didn’t.
The result was largely confined to hormone receptor-negative cancers – tumours that did not contain a protein to which oestrogen will bind. These cancers do not need oestrogen to grow, and usually don’t stop growing when treated with oestrogen-blocking hormones.
The study adds to other 2017 reports suggesting soy has other cancer-fighting properties. In February, researchers from the Universidade de Lisboa in Portugal reported its ability to inhibit enzymes linked to cell degradation in cancer growth. In a third study, biochemists from Aligarh Muslim University in Uttar Pradesh, India, revealed possible cancerfighting properties of a specific soy phytooestrogen called coumestrol.
WOMEN WHO CONSUMED LARGE AMOUNTS OF ISOFLAVONE HAD A 21% LOWER RISK OF DYING.
How isoflavones interact with cancer cells remains unclear. Nonetheless, says Zhang, “for women with hormone receptor-negative breast cancer, soy food products may potentially have a protective effect.”