Higher maternal selenium levels during pregnancy were associated with a lower risk of streptococcal infections in children, suggesting a potential protective effect.

Scientists from Hokkaido University have discovered that exposure to certain metals and trace elements during pregnancy may affect a child's risk of developing streptococcal infections, according to a new study published in PLOS ONE. These infections are common in children, especially those caused by Group A Streptococcus, a bacterium that frequently causes illnesses such as strep throat, skin infections, and, in severe cases, more serious complications like scarlet fever or invasive diseases. The findings could contribute to improved strategies for preventing childhood infections.

The research team tracked more than 74,000 mothers and their children from a nationwide study in Japan. They measured the mothers' blood levels of various metals and trace elements, including selenium, mercury, cadmium, lead, and manganese. The researchers then followed the children to see whether they developed streptococcal infections between the ages of three and four. Statistical analysis was used to explore potential links between maternal metal exposure and infection risk in the children.

"We found that mothers with higher selenium levels during pregnancy were less likely to have children WHO developed streptococcal infections," says Hiroyoshi Iwata, the study's first author, from the Centre for Environmental and Health Sciences at Hokkaido University. "This association was strongest among mothers with the highest selenium levels in their blood.

However, high selenium concentrations during pregnancy can lead to toxicity and adverse effects, so caution is necessary. As this research is based on a single blood sample provided by pregnant mothers, the results of this study alone should not be used to recommend selenium intake during pregnancy."

Selenium is a trace element that plays a key role in immune function, and previous studies have suggested that it may help the body combat infections by strengthening the immune system. These new findings support the idea that sufficient selenium levels during pregnancy could help enhance a child's immune defences against bacterial infections.

This study underscores the importance of ensuring adequate selenium intake during pregnancy for the benefit of children's long-term health and adds to a growing body of evidence suggesting that selenium plays a vital role in immunity.

However, this study specifically analyzed the relationship between maternal selenium levels and streptococcal infections only and did not evaluate the relationships with other infectious diseases. Further research is needed to fully understand how selenium supports the immune system and to determine the optimal levels during pregnancy.