Chemicals in soap 'may contribute to Western world's fertility problems', say scientists after lab study

Chemicals found in common household products can affect human sperm cell behaviour in the laboratory, according to a recent study.

Researchers from Denmark and Germany tested around one hundred common man-made chemicals called endocrine disrupters, or EDCs, found in products such as toothpaste and some sunscreens. They found that the chemicals can affect the ability of sperm to swim and to release enzymes needed to fertilise an egg.

'For the first time, we have shown a direct link between exposure to endocrine disrupting chemicals from industrial products and adverse effects on human sperm function', said Professor Niels Skakkebaek, leader of the Danish team from the Department of Growth and Reproduction at the Rigshospitalet in Copenhagen, Denmark.

There are concerns that EDCs are associated with a range of health problems and may affect male fertility by reducing the production of sperm. This study raises the possibility that the chemicals may also have an effect on other aspects of sperm behaviour important for fertility.

The study observed changes in normal sperm behaviour for approximately one third of the EDCs tested. Of these, 11 were tested at very low concentrations similar to those measured in human bodily fluids, and were found to have a similar effect on sperm function as that seen at higher concentrations.

'In my opinion, our findings are clearly of concern as some endocrine-disrupting chemicals are possibly more dangerous than previously thought. However, it remains to be seen from forthcoming clinical studies whether our findings may explain reduced couple fertility which is very common in modern societies', Professor Skakkebaek said.

This study was performed in vitro and some experts have pointed out that there may be a different effect in the human body. 'Whilst the authors have attempted to use concentrations of these compounds that are found in bodily fluids, this data is incomplete and the environment of the reproductive tract is quite unique and is not the same as blood, urine or saliva', said Dr Allan Pacey, Senior Lecturer in Andrology at the University of Sheffield.

Sir Colin Berry, Emeritus Professor of Pathology at Queen Mary, University of London said, 'The difficulty here is extrapolating from an in vitro test to an in vivo situation. At the levels apparently tested, some of the compounds involved do not affect fertility or pregnancy outcomes in the animals in which they have been tested'.

The European Commission is currently reviewing its policy on the use of EDCs. Lead author of the study, Timo Strünker, from the Center of Advanced European Studies and Research in Bonn, Germany, said 'Our study provides scientific evidence to assist forming international rules and practices'.

The study was published in the EMBO journal.