Sat Aug 24, 2013 (foodconsumer.org) -- A new Japanese study published in Current Nutrition and Food Science suggests that using a particular probiotic beverage and soy isoflavone consumption since adolescence can reduce the risk of breast cancer significantly.

The case-control study led by M. Toi from School of Public Health The University of Tokyo in Tokyo, Japan and colleagues shows that both a beverage with Lactobacillus casei Shirota (BLS) and soy consumption since adolescence were independently associated with up to 50% reduced risk of breast cancer.

For the study, 306 cases of breast cancer and 662 controls aged 40 to 55 were compared for their diet, lifestyle and other breast cancer risk factors which were surveyed through a self-administered questionnaire and an interview.

Drinking the beverage with Lactobacillus casei Shirota four or more times a week was associated with 35% reduced risk of breast cancer, which is significant, compared with those drinking the probiotic beverage fewer than four times per week.

Similarly, those in the highest quartile of soy consumption (soy isoflavone consumption) were 52% less likely to develop breast cancer, compared with those in the lowest quartile.  There was an inverse association between soy isoflavone consumption and the risk of breast cancer.

Also, there seemed to be a BLS-isoflavone interaction which was statistically non-significant though.

The researchers concluded "Regular consumption of BLS and isoflavones since adolescence was inversely associated with the incidence of breast cancer in Japanese women."

In many cases, breast cancer is preventable.  The disease is diagnosed in more than 230,000 women in the United States annually and the disease and its complications kill more than 37,000 women every year in the U.S alone.

An authoritative organization suggests that two most certain breast cancer risk factors are hormone replacement therapy and radiation even though many other risk factors may also contribute to the development of the disease. (david liu)