High intake of certain plants may double aggressive prostate cancer risk

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High intake of certain plants may double aggressive prostate cancer risk

A high consumption of certain plant-based foods may double a man’s risk of developing an aggressive form of prostate cancer, according to an Indiana University study.  The study appeared in the International Journal of Cancer and was titled “Dietary Intake of Isoflavones and coumestrol and the risk of prostate cancer in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial.”

hytoestrogens are a family of estrogen-like bioactive

compounds found in plants.

4

Individual phytoestrogens

derived from dietary sources are classified into three major

categories: isoflavones (e.g., genistein, daidzein, glycitein, for-

mononetin and biochanin A), lignans (e.g., matairesinol an

hytoestrogens are a family of estrogen-like bioactive

compounds found in plants.

4

Individual phytoestrogens

derived from dietary sources are classified into three major

categories: isoflavones (e.g., genistein, daidzein, glycitein, for-

mononetin and biochanin A), lignans (e.g., matairesinol an

Plant-derived compounds called phytoestrogens are a family of estrogen-like bioactive compounds found in plants. Individual phytoestrogens derived from dietary sources are classified into three major categories - isoflavones, lignins, and coumestans.  It was these three major categories of phytoestrogens that the study researchers analyzed for their effect on prostate cancer. 

Isoflavones are a class of phytoestrogen which are plant-derived compounds with estrogenic activity.  The richest sources of isoflavones are soybeans and other soy products along with kudzu root, and American groundnuts.  The compounds of isoflavones include genistein, daidzein, glycitein, formononetin, and biochanin A. 

Lignans are polyphenols found in plants with flaxseeds being the richest dietary source along with green tea and strawberries.  They have a weak estrogenic activity but may also exert biological effects through nonestrogenic mechanisms. 

Coumestans are a derivative of courmarin and forms the center core of a variety of natural hormones.  This compound can be found in alfalfa sprouts and clover, and several varieties of beans such as split peas, pinto beans, and lima beans. 

The research focused on work done by previous studies in animals which have suggested that a diet rich in these compounds can reduce levels of the male hormone testosterone which could possibly increase the risk of prostate cancer.  In a previous study using mice, it found that mice who were fed genistein, a compound of isoflavones, not only increased the risk of developing prostate cancer but also caused it to spread to other areas of the body.

Past experimental studies on animals have shown that phytoestrogens may increase the risk of breast and prostate cancer.  The aim of this new study was to investigate whether intake of these compounds may influence prostate cancer risk in human populations. 

Researchers at Indiana University looked at 27,004 men for a median of 11 ½ years by asking them with questionnaires to report their consumption of plant-based foods. The participants for the study came from the Prostate, Lung, Colorectal, and Ovarian Screening Trial. While the study was being conducted, doctors diagnosed 2,598 cases of prostate cancer, of which 287 were advanced cases.  When researchers matched the questionnaire results to the diagnoses, it was determined that consumption of tofu and soybeans, peas, and tea were the main contributors to isoflavones consumption. 

The researchers found that high consumption of isoflavones doubled the risk of a man’s chance of developing advanced prostate cancer.  The isoflavone genistein increased the risk of advanced prostate cancer by 50 percent, daidzein by 80 percent, and glycitein by 67 percent.

It is important to note that there was no significant association found between isoflavone intake and the development of non-advanced prostate cancer. 

The main takeaway from this study was that the dietary intake of isoflavones has different effects on advanced versus non-advanced prostate cancer.  It does help scientists come to a better understanding of the causes of advanced prostate cancer but there is still more work needed through epidemiological studies before it any dietary changes or recommendations can be made depending on a man’s dietary habits.