Prolonged consumption of flaxseed flour increases the 17b-estradiol hormone without causing adverse effects on the histomorphology of Wistar rats' penis.

Consumption of foods rich in phytoestrogens such as flaxseed has increased due to its chemoprotective effects, especially those related to the cardiovascular system. The flaxseed has components that can interfere with development of male reproductive system. This study aims to investigate the possible effects of prolonged consumption of flaxseed flour on hormonal and histomorphologic penis parameters of adult Wistar rats. Rat dams were divided into two groups during lactation period: the control group that was fed with diet based on casein and the flaxseed group that was fed with diet based on casein containing 25percent of flaxseed. At weaning, 10 male offspring from each group continued to receive the experimental diets until 250 days old. Rats fed with diet containing flaxseed showed increased concentrations of 17b estradiol (p  0.01) but no changes in testosterone concentrations. With regard to histomorphometric analysis of the penis, supplemented rats had lower values for the total area of the corpus spongiosum (p 0.01). All other analyzed parameters were similar as the control. Results showed that the use of flaxseed flour did not cause adverse effects on the penis morphology but increases the 17b estradiol hormone, when consumed in integral form for a prolonged period. (Authors abstract)

Daily use of flaxseed provides fiber, alpha linolenic acid, and lignans for a healthy diet.  The seed also contributes to a lower omega 6 to omega 3 ratio.  High consumption of phytoestrogens may protect against hormone dependent cancers.  Flaxseed contains substances that may interfere with the development of the male reproductive system, and can exert both protective and adverse effects, depending on dose, exposure time, and life stage in which it is administered. Published papers are controversial and they evaluated only the flaxseed consumption for a short time. Thus, studies are needed to check the possible effects of prolonged consumption of flaxseed flour on histomorphological and hormonal parameters of the adult Wistar rats penis. In men, the main source of estrogens is from the conversion of testosterone into estradiol catalyzed by the enzyme aromatase. Flaxseed lignans are proved to be competitive inhibitors of aromatase enzyme but in this study found an increase in 17b estradiol and decreasing tendency in testosterone.  This increase found in 17b estradiol may be critical to the penis. The present study and published papers suggest that the male reproductive organs respond differently against the exposure to phytoestrogens and this response can vary with the dose, exposure time, and life phase.  Further studies are needed to evaluate the effect of flaxseed consumption for the penis and ensure the safety of chronic consumption of this seed, since no studies were found that had evaluated the impact of this seed on the erection and morphometric and histological parameters.  In this work, the use of flaxseed flour did not promote adverse effects on the penis. The authors are continuing their analyses. (Editors comments)