A novel study has found that fluoride is linked to lower IQ in children. Here’s why you shouldn’t worry

Fluorine is a common natural element found in water, soil, rocks and food. Fluoride has also been a cornerstone of dentistry for the past several decades public healthdue to its anti-caries properties.

Water fluoridation is a population-based program in which a precise, miniature amount of fluoride is added to public drinking water systems. Water fluoridation began in Australia in the 1950s. Today over 90% of Australia’s population has access to fluoridated tap water.

But recently published review found that higher fluoride exposure is associated with lower intelligence quotient (IQ) in children. So how can we interpret the results?

Most of the evidence analyzed in this review is of low quality. Overall, the findings do not give us cause for concern about fluoride levels in our water supplies.

This is not a novel controversy

Tooth decay (also known as tooth decay or cavities) can have a negative impact on dental health, overall health and quality of life. Fluoride strengthens our teeth, making them more resistant to caries. Is scientific consensus Water fluoridation is a safe and sound, effective and equitable method to improve oral health.

Nevertheless, water fluoridation has been quite controversial in the past.

The potential link between fluoride and IQ (and cognitive function more broadly) has been a controversial topic over a decade. It started with reports from research conducted in China and India.

It should be noted, however, that these studies were restricted by destitute methodology, and the water in these countries had high levels of natural fluoride at the time the studies were conducted – many times higher than the levels recommended in water fluoridation programs. The studies did not control other contaminants in water supplies.

Last reviews focusing on fluoride level used in water fluoridation concluded that fluoride is not associated with lower IQ.

Still, some continued to express concerns. The United States National Toxicology Program was conducted review potential link. However, this review did not pass quality assessment by the United States National Academy of Sciences, Engineering, and Medicine due to significant limitations in conducting the review.

The authors continued the study and published it as an independent publication in a journal JAMA Pediatrics last week. That’s the research generating media attention in recent days.

What the study showed

The study was a systematic review and meta-analysis in which researchers assessed 74 studies from different parts of the world.

A total of 52 studies were deemed to be at high risk of bias, and 64 were cross-sectional studies that often cannot provide evidence of causality.

Most studies were conducted in developing countries such as China (45), India (12), Iran (4), Mexico (4), and Pakistan (2). Only a few studies have been conducted in developed countries with public water systems where regular monitoring and treatment of drinking water ensures it is free from contaminants.

The immense majority of studies have been conducted in populations with high or very high levels of natural fluoride and without water fluoridation programs in which fluoride levels are controlled within recommended limits.

The study found that there is an inverse relationship between fluoride levels and IQ in children. This means that those children who consumed higher fluoride intakes had lower IQ scores than their peers.

Limitations to consider

Although many studies were included in this review, there are several limitations that cast sedate doubt on its conclusions. Scientists immediately raised concerns about the quality of reviews, including: related editorial published in JAMA.

The main problem is the low quality of most of the included studies, which means that the quality of the review is equally low. Importantly, most studies have not examined recommended fluoride levels in water fluoridation programs.

Several studies conducted in countries with controlled public water systems (Canada, Fresh Zealand, Taiwan) found no negative effects. Other recent studies conducted on comparable populations (e.g Spain AND Denmark) also did not show any negative effect of fluoride on IQ, but were not included in the meta-analysis.

For context, the review found that there was no significant association with IQ when the fluoride concentration in the water was less than 1.5 mg per liter. In Australia, recommended levels of fluoride in public water supplies range from 0.6 to 1.1 mg/l.

Additionally, the main outcome is the IQ score difficult to collect. Most included studies varied significantly in the methods used to collect IQ data and did not specify whether they focused on providing reliable and consistent IQ data. Although this is a challenge in most research on this topic, significant differences between the studies reported in this review raise further doubts about the combined results.

There is no reason to worry

Although no Australian studies were included in the review, Australia has conducted its own research examining the potential link between early childhood fluoride exposure and child development.

I participated in a population-based longitudinal study examining the relationship between fluoride and the child’s behavioral development and executive functioning and in between fluoride and IQ. IQ data in the second study were collected by qualified, trained psychologists and calibrated against a senior psychologist to ensure quality and consistency. Both studies provided robust evidence that fluoride exposure in Australia does not negatively impact child development.

This novel review is no cause for concern about fluoride levels in Australia and other developed countries with water fluoridation programs. Fluoride remains crucial for maintaining the dental health of the public, especially vulnerable groups.

That said, attention should be paid to the high and uncontrolled levels of fluoride in water supplies in less developed countries. There they are programs in progress in many countries to limit natural fluoride to recommended levels.