Study title and authors:
Soy food and isoflavone intake in relation to semen quality parameters among men from an infertility clinic.
Chavarro JE, Toth TL, Sadio SM, Hauser R.
Department of Nutrition, Harvard School of Public Health, Boston, MA, USA. email@example.com
This study can be accessed at: http://www.ncbi.nlm.nih.gov/pubmed/18650557
The study examined the association of soy foods and soy isoflavones with sperm concentration. The intake of 15 soy-based foods in the previous 3 months was assessed for 99 male partners of subfertile couples who presented for semen analyses to the Massachusetts General Hospital Fertility Center.
The study found:
(a) Men in the highest category of soy food intake had 41 million sperm/ml less than men who did not consume soy foods.
(b) Results for individual soy isoflavones were similar to the results for soy foods and were strongest for glycitein.
Chavarro concluded: "These data suggest that higher intake of soy foods and soy isoflavones is associated with lower sperm concentration."