>And finally: does anyone have any info on the effect of large soy consumption on males?
There are no effects on male biology across a range of parameters tested. There have been many studies done on the effects of isoflavone ingestion on men. Long-term studies on adult men show very little effect. There are in my opinion only two important unanswered questions:
* there are few to no truly long-term studies of soy isoflavone intake in adolescent and pre-adolescent boys, particularly at high levels of intake, although there is of course some ethical concern in running such a study. Some studies in young men have shown small effects ( http://jn.nutrition.org/content/135/3/584.long ).
* studies do not tend to measure effects which are related to the genitalia and sexuality. In general, they only measure hormone levels, which are merely a proxy for real effects, and may not be a reliable one.
To address this problem I have been sort of sketching a small-scale machine that processes unshelled hempseeds into hemp milk or butter. Unshelled hempseeds are the only actual food (i.e. not an extract/powder) on store shelves with a high protein content that aren't soy or animal products and aren't crazy expensive. Shelling hempseeds mechanically, without crushing, is extremely difficult, but the kernel sinks in water, whereas the shell floats, allowing for a very easy separation if the seeds are crushed. That got off topic fast. Anyway:
However, there are probably effects resulting from activation of estrogen receptor beta. The reason is that activation of ERB is known to suppress prostate cancer, and soy consumption also suppresses prostate cancer:
Studies do not generally look for behavioral effects of activation of ERB by soy isoflavones because of the difficulty of measuring those. However, in some cases, meat consumption actually resembles soy consumption:
>In conclusion, our data suggest that the ability of Caucasian men to produce equol is favorably influenced by the long-term consumption of high amounts of soy and the consumption of meat.
Since a great deal of animal feed is soy-based this phenomenon may have a simple explanation. However, dairy does not cause this effect (animals' bodies may be trying to avoid intoxicating their young).
There are no effects on male biology across a range of parameters tested. There have been many studies done on the effects of isoflavone ingestion on men. Long-term studies on adult men show very little effect. There are in my opinion only two important unanswered questions:
* there are few to no truly long-term studies of soy isoflavone intake in adolescent and pre-adolescent boys, particularly at high levels of intake, although there is of course some ethical concern in running such a study. Some studies in young men have shown small effects ( http://jn.nutrition.org/content/135/3/584.long ).
* studies do not tend to measure effects which are related to the genitalia and sexuality. In general, they only measure hormone levels, which are merely a proxy for real effects, and may not be a reliable one.
To address this problem I have been sort of sketching a small-scale machine that processes unshelled hempseeds into hemp milk or butter. Unshelled hempseeds are the only actual food (i.e. not an extract/powder) on store shelves with a high protein content that aren't soy or animal products and aren't crazy expensive. Shelling hempseeds mechanically, without crushing, is extremely difficult, but the kernel sinks in water, whereas the shell floats, allowing for a very easy separation if the seeds are crushed. That got off topic fast. Anyway:
https://www.researchgate.net/profile/Sue_Duval/publication/2...
However, there are probably effects resulting from activation of estrogen receptor beta. The reason is that activation of ERB is known to suppress prostate cancer, and soy consumption also suppresses prostate cancer:
http://onlinelibrary.wiley.com/doi/10.1002/ijc.21266/full
Studies do not generally look for behavioral effects of activation of ERB by soy isoflavones because of the difficulty of measuring those. However, in some cases, meat consumption actually resembles soy consumption:
http://jn.nutrition.org/content/135/6/1400.long
>In conclusion, our data suggest that the ability of Caucasian men to produce equol is favorably influenced by the long-term consumption of high amounts of soy and the consumption of meat.
Since a great deal of animal feed is soy-based this phenomenon may have a simple explanation. However, dairy does not cause this effect (animals' bodies may be trying to avoid intoxicating their young).