There is evidence that phytoestrogens (plant estrogens) protect people from prostate cancer. This study in Sweden was done to evaluate patients in a large group of men to see if enterolactone blood levels or increased phytoestrogen intakes reduced the risk of cancer. Enterolactone is a metabolite of lignan that indicates the level of lignans a person consumes. Extensive diet questionnaires were completed and blood samples were taken. Cancer patients were matched with controls without prostate cancer.
The following are the three types of phytoestrogens: Coumestans, Isoflavonoids, and Lignans.
Lignans are found in various grains, breads and cereals. Fecal microflora (bacteria) convert plant lignans to mammalian lignans.
High phytoestrogen consuming populations have been shown to have less prostate cancer in population studies.
Natural phytoestrogens are in plants. There is less cancer among people consuming a Western diet if isoflavonoids or soy products are consumed. One study showed less prostate cancer among those who ate high lignan foods.
The authors studied patient’s diets for sources of phytoestrogens. Flax seeds and rye bread contributed most to the lignan consumption in this study and soy was the main origin of isoflavonoids for this study.
The normal controls in this study had higher enterolactone levels and the authors found that high total phytoestrogen foods for this population were flax, sunflower seeds, berries, peanuts, beans and soy. The highest consumers of these foods had a 26% reduction in prostate cancer as compared to the lowest consumers. Intake of the individual types of phytoestrogens in this study did not seem to change cancer risk, just the total phytoestrogens.
CONCLUSION: All that can be said is the high phytoestrogen intakes lower prostate cancer risk. No specific type of phytoestrogen seemed to be more important than the others.
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