Soy and other plants found to reduce breast cancer recurrence
CANCER DIGEST – Jan. 12, 2024 – Consumption of the equivalent of one cup of soy milk per day reduced the risk of breast cancer recurrence by 26 percent, a new analysis of data from 22 studies shows.
In addition, the analysis linked consumption of seeds, nuts, legumes, whole grains and flax seed among others, reduced the risk of death from any cause by 35 percent in postmenopausal women.
The study led by researchers at the BNICM HealthResearch Institute of Western Sydney University in Australia involved a review of data from 22 studies by investigators in Australia, Denmark, England, Norway and the U.S. The study analysis was co-directed by investigators from Johns Hopkins Kimmel Cancer Center and were published in the Jan. 10 journal NCI Cancer Spectrum.
“It is critically important to stress that these studies were conducted on women who received medical and/or surgical treatment for breast cancer, and that these foods and phytonutrients should not be considered as alternatives to treatment,” senior study author Channing Paller, M.D., director of prostate cancer clinical research and an associate professor of oncology at Johns Hopkins said in a press release.
All of the studies were observational, meaning investigators follow a group of people, in this case women who had been treated for breast cancer, for a period of time to observe the effect of certain risk factors.
In this study, analysis of data from six of the 22 studies showed that post menopausal breast cancer patients who consumed the equivalent of two to three servings of soy per day, where one serving equates to a cup of soy milk, three ounces of tofu or a half-cup of cooked soybeans, had a 26 percent reduction in their risk of breast cancer recurrence.
Another finding of the analysis was a 28 percent reduction in breast cancer death among women who consumed enterolactone, a compound produced from the digestion of lignans, which are found in seeds, nuts, legumes, whole grains, and fruits and vegetables. High levels of enterolactone are found in flaxseeds, cashew nuts, broccoli, brussels sprouts and other vegetables.
The researchers note that is not possible to calculate the effective dose of such lignans in the diet due to differences in individual metabolism.
The study also found less conclusive links to cancer risk reduction for green tea, and consumption of cruciferous vegetables, however, the researchers noted that this was largely because the average amounts of these foods consumed tended to be quite low in the studies reviewed.
The investigators concluded that this study highlights the need for more studies looking into the most effective doses of these compounds, and whether beginning consumption after diagnosis has the same effect.
Source: Johns Hopkins Medicine press release