Scientists have discovered that chemicals found in household products, such as soap, toothpaste and plastic children’s toys could impact on human sperm, which may explain the increased levels of infertility in males.
This is the first time a study has found this direct effect of man-made chemicals on an important function of the human sperm. These findings will raise concerns about the hidden levels of toxicity in chemicals which are deemed to be safe based on toxicology tests.
The researchers believe they have found a new method of testing the impact of these chemicals on human sperm. This should provide the European regulatory authorities with sufficient information to make a decision on whether they should ban or impose restrictions on the use of these chemicals in certain products.
The study was done as part of wider research into what is called ‘endocrine-disrupting’ chemicals which have been linked to widespread male infertility and falling sperm counts. The chemicals are thought to mimic oestrogens, female sex hormones, and in some cases may act as the male sex hormones, anti-androgens, which interferes with the reproductive system of males.
Scientists found that a third of common household chemicals which were present in detergents, plastics and sun screens were responsible for sabotaging the swimming behaviour of human sperm. It caused premature release of the enzymes required for the penetration and fertilisation of the egg cell. This made the sperm infertile.
The scientists also discovered that the concentrations required to start the adverse reactions were similar to the extremely low levels that were normally found in the body. This indicated that there was a ‘cocktail effect’ whereby a range of chemicals worked in unison to boost the individual effects.
Professor Niels Skakkebaek from Copenhagen University Hospital stated that their findings are of concern as some of the endocrine-disrupting chemicals may be more dangerous than it was previously envisaged. However, he stated, that future clinical studies will determine if their findings can explain increased infertility in couples which has become commonplace nowadays.
Professor Skakkebaek is a pioneer in the investigation of the increase in male infertility. During 1991, he produced the initial evidence that human sperm counts had decreased by approximately 50% in less than 50 years.
A few years thereafter, scientists discovered that there common chemicals that affected the ‘oestrogenic’ or ‘antiandrogenic’ effect on the reproductive system of males. This plays a huge part in the development of a male foetus in the womb, particularly during the first six months when the reproductive tissues are being formed.
The latest study showed that 30 of 96 common household chemicals had a direct impact on the ‘catsper’ protein which is responsible for the control of the sperm cell’s movement and ability to enter the egg cell for fertilisation.
Dr Strünker stated that complex chemical cocktails are found in body fluids and they tried to mimic this situation for their experiments. He stated that when these chemicals are mixed together, even with the low ingredient concentration, it allowed for large responses in the sperm. What has not been indicated before is how the complex mixtures of the chemicals work together to interfere with the function of sperm.
People ingest all these chemicals on a daily basis, through the food and drink which has been contaminated, or by using soaps and personal care products.
Image Credit: Adam Rosenberg