Soybean and Flaxseed Lower Testosterone Levels and Libido

[Jinzang]

The long standing debate over whether phytoestrogens lower testosterone levels got some new evidence that they do. The experiment was done on buck rabbits, but I see no reason that the result should not also apply to people. 21 rabits were divided into 3 groups and fed soybean meal, linseed (flaxseed) meal or neither. Both soybean and linseed are good sources of phytoestrogens, though the type differs between the two. The conclusion of the abstract states:

Prolonged consumption of dietary isoflavones or lignans did not impair semen fertilizability. This may be due to the benefits of antioxidant activity or due to the benefits of other components in the diet. Dietary phytoestrogens did evoke obvious decreases in libido and steroidogenesis with altered semen parameters.