A new study by scientists at the Johns Hopkins School of Public Health has caused concerns about the safety of soya. The scientists have called for urgent research into the impact of soya on unborn children following tests on rats which suggest a chemical in soya can damage the male reproductive organs. Though there is no evidence to suggest it has a similar effect on humans, its effects on rats were so severe that researchers believe that further tests are needed to ensure it is safe for pregnant women to eat.
In the study conducted by the researchers, pregnant rats were fed a diet laced with genistein - a chemical found in soya. The scientists found that male rats exposed to high levels of genistein in the womb grew up to have larger prostate glands and smaller testes. The rats had normal sperm counts and would behave as if they wanted to mate when placed with females. However, they were unable to ejaculate. The effects were just as severe in males that did not eat genistein after weaning as it was in those that continued eating it. These results indicated that exposure in the womb and during breast feeding has the biggest impact. The researchers also found that the male rats exposed to genistein had a slightly large thymus gland, an organ that produces immune cells. They also found that moderate levels of genistein had an even bigger effect on male rats than large doses.
Researchers concluded that the findings of the study has caused concern and urologists connected with this project are actually advising pregnant women to avoid soya. They added that though the study is not conclusive, it highlighted the need for further research.