Do French men have to fear for their fertility?
In France, the number of sperm has decreased by a third. Do French men therefore have to fear for their fertility? According to a recent study, men in the Paris region are particularly affected. Environmental factors and industrial chemicals could be responsible for the drastic reduction in sperm count.
Sperm quality also decreases
More than 26,600 men in France took part in the large-scale nationwide survey, which came to a dramatic conclusion: the number of sperm cells has decreased by a third in the past 17 years. "There was a significant and continuous decrease in sperm concentration of 32.2 percent during the duration of the study," the researchers report in the journal "Human Reproduction." Projections suggest that the concentration in a 35-year-old man from an average of 73.6 million per milliliter of sperm in 1989 to an average of 49.9 million in 2005. "A value of less than 55 million sperm cells per milliliter of sperm can have a negative impact on fertility, as some studies have shown. Sperm is sterile with a concentration of less than 15 million sperm.
"A significant, but not quantifiable, decrease in the proportion of sperm with morphologically normal forms was also observed during the 17 years," the scientists continue. The quality of sperm in France may have been declining since the 1970s. It is a "serious warning sign". According to the authors of the study, "the study is the most important and largest of its kind in France, possibly worldwide".
Sperm return due to environmental and disruptive factors
For some years now, scientists have been blaming environmental or disruptive factors for the decline in sperm counts. Pesticides and plasticizers in particular are said to have a negative impact on fertility. However, it is difficult to identify a single substance, since humans are usually exposed to several health-related factors these days, said reproductive expert Louis Bujan from the Toulouse University Clinic. This could be a reason why the Paris region, in which a large number of health-threatening disruptive factors occur, is particularly affected by the decline in sperm cells. Obesity and tobacco use also have a negative impact on sperm production.
Bisphenol A affects sperm
One of the disruptive factors is the plasticizer "bisphenol A" (BPA), which is found in many everyday products. "The effect of BPA is similar to that of the female hormone estrogen and thus influences the hormonal balance in humans", as some studies sum up. In November 2010, Chinese scientists presented a study that demonstrated a link between BPA and reduced sperm production.
The researchers collected data from 218 workers in four different factories in China. The concentration of the plasticizer BPA in the urine was measured by workers who did not come into contact with bisphenol A during the manufacturing process and others who were in contact with BPA through their work. These data were then compared with the number of sperm, their motility and shape. The researchers around Dr. De-Kun Li from the US insurance company “Kaiser Permanente” in Oakland, California evaluated the data.
The workers who had daily contact with the chemical clearly showed higher risk factors. In contrast to the comparison group, their spermatozoa were more than twice as likely to have reduced mobility and more than three times more likely to be less vital. There was a four-fold increased risk for a greatly reduced number of sperm. A connection between BPA and deformed sperm was not proven in the study.
High fat foods can make you sterile
A study by US researchers at Harvard Medical School and the Harvard School of Public Health in Boston could possibly result in male infertility due to excessive consumption of saturated fats.
As researched by Jill Attaman of Harvard Medical School in the journal Human Reproduction in March of this year, their study showed that the number of sperm in men with particularly high fat consumption was significantly lower than in the other study participants. This is due to the saturated fatty acids contained. The increased consumption of unsaturated omega-3 fatty acids, on the other hand, would have a positive impact on sperm production, which increased slightly, the researchers said. (sb)
Sperm cannot smell
Obesity reduces sperm quality
A high-fat diet damages sperm quality
Men are becoming more and more sterile
Image: Thommy Weiss / pixelio.de