The men who consumed soy products of the regularly would produce less sperm than the other, according to American researchers. They do not however not go as far as establishing a tie between the soy and the male infertility.
Several studies on the consumption of isoflavones and the production of sperm have been made on animals, but few data exist about the effects of the products of the soy on the male fertility. This survey is the first to be led on an as big number of men.
The researchers of the Faculty of the Sciences of the nutrition of the Harvard School of Public Health recruited 99 men having consulted the experts of a fertility clinic. The participants filled the questionnaires concerning their consumption of various food containing the soy: tofu, tempeh, soy milk of, or of the products containing substantial quantities of soy as sausages, of meats, of cheese, the drinks, energizing the bars, the frozen cream, etc..
According to the results, those that consumed more of the soy (either a cup of soy milk or a piece of tofu every other day) had less sperm in their semen that those that had never consumed soy.
No hasty conclusion
The concentration of spermatozoa of the topics varied between a minimum of a few less than 20 million / ml of semen and a maximum of a few more of 220 million / ml. Of the results that do not have anything abnormal since one observes such differences in general in the male population. The experts estimate that a concentration of 20 million / ml is sufficient to assure fertility.
As for the middle concentration of sperm, she / it was located to a few less than 60 million / ml among the biggest consumers of soy compared to a few more of 100 million / ml at those that never consumed some.
According to the data of the survey, the quantity of sperm was systematically lower among the patients who consumed more of the products to basis of soy in comparison of those that never consumed some.
This difference was especially marked at the very men who had an account of sperm above the average, while it reduced considerably at those of which the concentration of sperm was lower to the average.
These results do not allow the authors of the survey to pull a conclusion about the real effects of the soy on the male fertility since a man who produces less sperm than another is not necessarily fertile.
The overweight in reason?
The researchers make otherwise notice that the number of men displaying a bodily excess weight was raised very among the participants. The men making the plumpness of obesity or suffering represented about 72% of the group.
The authors of the survey estimate that the overweight could return the men more sensitive to the effects of the environmental phytooestrogènes, but it is at present only about a hypothesis.
Some Scottish researchers lately arrived to the conclusion that the obesity could reduce the quality of the semen.
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