Fluoride in water linked to lower IQ in children: Government report

Water with twice the recommended limit of fluoride has been linked to lower IQs in children, according to a Department of Health and Human Services report.

The Wednesday report, from HHS’s National Toxicology Program, acknowledges the potential neurological risk of high levels of fluoride exposure “with moderate confidence,” the second-highest level of confidence used by the NTP. While the report, which is an analysis of previous research, did not quantify the number of IQ points lost due to exposure, some of the research cited say children with higher exposure can lose between 2 and 5 IQ points.

“Since 1945, the use of fluoride has been a successful public health initiative for reducing dental cavities and improving general oral health of adults and children,” the report stated. “There is a concern, however, that some pregnant women and children may be getting more fluoride than they need because they now get fluoride from many sources including treated public water, water-added foods and beverages, teas, toothpaste, floss, and mouthwash, and the combined total intake of fluoride may exceed safe amounts.”

Water fluoridation is the practice of adding fluoride to fresh water sources because the Centers for Disease Control and Prevention claims it prevents cavities and tooth decay.

Most water sources do contain naturally occurring fluoride, but municipal water sources boost the numbers because the natural levels are “too low to prevent cavities,” the CDC says.

The practice of fluoridation has always drawn controversy from those who believe the government should not be putting chemicals in the drinking water without the consent of those who will be drinking it. Critics say that it is a coerced medical treatment.

Proponents of fluoridation consider it to be a major public health achievement, bringing dental prices down and prolonging the use of natural human teeth throughout a lifetime. The American Dental Association is a major supporter of water fluoridation.

While people come in contact with fluoride through multiple sources, such as toothpaste, researchers say water is the primary source of the mineral.

The new report, however, says that all the efforts to prevent cavities have been connected to lower IQs in children with fluoride intake twice the recommended limit.

Drinking water with more than 1.5 milligrams of the chemical per liter was associated consistently with lower IQs in children. That level is the current safe limit set by the World Health Organization. The report did not test for the same association with adult cognition.

The current dosage recommendation from the U.S. Public Health Service is 0.7 milligrams per liter. The report states that there was “insufficient data” to determine if the current level has a negative effect on children’s IQ and that more studies needed to be conducted.

According to the report, about 1.9 million people in the United States, roughly 0.6%, are exposed to fluoride levels at 1.5 milligrams per liter or higher.

“The findings from this report raise the questions about how these people can be protected and what makes the most sense,” said Ashley Malin, a researcher at the University of Florida who has studied the effects of fluoride on pregnant women and children.

According to the Environmental Protection Agency, water systems are not allowed to have above 4 milligrams per liter of fluoride because that level can cause skeletal fluorosis, a serious condition that causes weaker bones, stiffness, and pain.

An increasing number of studies in animals have suggested that fluoride exposure affected cell function in regions of the brain that control learning, memory, executive function, and behavior. Researchers have been interested to learn if those effects transfer over to humans, and if young children who may be exposed to fluoride through water used to mix baby formula were seeing a negative impact.

A 2006 study from the private nonprofit National Research Council brought the question of neurological effects of from fluoride in humans to the fore, using limited evidence available from China, and it called for more research.

The NTP started to review the available evidence in 2016 in order to find if more limiting measures for fluoride exposure may be needed.