Optimal diet with soy proteins can normalize the testosterone level for prostate health

Optimal diet with soy proteins can normalize the  testosterone level for prostate health

A biased, mis-analyzed research result on soy proteins in
http://cebp.aacrjournals.org/content/16/4/829.full.pdf+html
The result has been challenged byhttp://cebp.aacrjournals.org/content/16/12/2795.long
Mark Messina1, Jill Hamilton-Reeves2, Mindy Kurzer3 and William Phipps4
- Author Affiliations
1Nutrition Matters, Inc., Port Townsend, Washington; 2College of St. Catherine, St. Paul, Minnesota; 3University of Minnesota, Minneapolis, Minnesota; and 4University of Rochester, Rochester, New York

According to Figure 1 of this paper, Soy protein @56 gram a day normalizes the testosterone level. The SP#2 drops from an extreme high level of 1300 ng/dl (that may cause prostate cancer) to about 500 ng/dl. Excluding SP#2, the average testosterone level increases slightly. Soy protein intake @56 grams a day produces a positive result accordingly. However, I recommend 30 grams a day for better sex (lasting longer) and prostate health.  Soy + Zinc is good your liver to reduce the aromatase enzyme release.
By the way, you should have a balance diet with random intake of proteins, animal or plant sources. You should not consider soy is the only main source of your protein intake. Personally, I like sea-food proteins.