June 24, 2010
A new study reported in the June 16 2010 issue of Journal of Medicinal Food suggests that eating soy and Brazil nuts may help fight prostate cancer.
The study led by Kumi-Diaka J. from the Florida Atlantic University found a genistein-selenium combination promotes apoptosis of prostate cancer cells, programmed cell deaths.
Genistein is a metabolite of soybeans and selenium is found high in Brazil nuts. Photochemicals in soy have been found to be antimutorigenic and may protect against human cancers.
In the study, the researchers tested the effects of the genistein-selenium combo on chemosensitivity and matrix metalloproteinase-2 (MMP-2) expression in hormone-independent PC3 prostate cancer cells and hormone dependent LNCaP prostate cancer cells.
Individual genistein and selenium and a combination of the two all significantly inhibited the growth of both types of prostate cancer cells and the expression of MMP-2 in a dose- and time-dependent manner regardless of its hormonal status.
MMP-2 expression in cancer cells has been associated with active invasion and metastasis, according to the researchers.
The genistein-selenium combo was most effective in inhibiting the growth of the prostate cancer cells of both types.
All the inhibition was realized through the induction of apoptosis and was caspase-dependent.
Genistein and selenium or the combo had no effect on the healthy prostate epithelial cells.
The researchers suggested that genistein and selenium or the combo may be used to prevent prostate cancer or treat the disease as an adjuvant therapy.
The majority of soy produced in the U.S. are genetically modified and some studies suggest that eating GM soy may not be safe. Eating too much of selenium can also exert some toxic effect.
Selenium is found high in shrimp, crab meat, halibut and salmon fish in addition to Brazil nuts. But Brazil nuts contain much higher levels of selenium.
Prostate cancer is diagnosed in about 190,000 men in the United States each year and the disease kills about 35,000 men each year in the country, according to the National Cancer Institute.