Water fluoridation may not be as good for you as you previously thought. Added to public water supplies, fluoride in water helps reduce tooth decay.
Now, a new study published in JAMA Pediatrics has discovered that having fluoride in water may be linked to children with lower IQ levels, if the mothers drink a certain amount while pregnant.
US Public Health Service could be mistaken
The findings aren't necessarily groundbreaking, as the link of water fluoridation to lower IQs has been made before. What's interesting here is that the US Public Health Service has claimed that 0.7 milligrams of fluoride in public drinking water is a safe amount.
The study examined 601 Canadian women and their children, observing the fluoride intake of 512 of the mothers. The team examined the pregnant women's urine samples.
All the children born from the women in the study had their IQs tested when they were three and four years old.
What the researchers discovered was that for each additional 1 milligram per liter in the concentration of fluoride that was found in the women's urine, their boys - not girls, so far - had a lower IQ by 4.5 points.
Girls didn't have a change in their IQs, but the research did not focus on why boys were affected and not girls. Something the team will be looking into next.
It may not seem like big numbers but added together, "At a population level, that's a big shift. That translates to millions of IQ levels lost," said Christine Till, the author of the study, and an associate professor in the Department of Psychology at York University in Toronto.
The researchers also controlled the studies' participants' income and education, as well as other exposures to elements such as lead and mercury.
The team has specified that more research needs to be carried out, especially on why boys are affected and not girls, but this could change how we perceive the safety of fluoridation in water.