High levels of fluoride have been linked to lower IQ in children. Fluoride is a mineral found naturally in water, soil, and plants. It is added to toothpaste products and many over-the-counter medications.

Although fluoride intake is safe within given limits, consuming it in large amounts can be dangerous. The US government’s National Toxicology Program (NTP) recently conducted a meta-analysis that highlighted the potential neurodevelopmental risks associated with excessive fluoride exposure.

The study found a statistically significant association between higher fluoride exposure and lower IQ scores in children, raising questions about the balance between fluoride’s dental benefits and its broader health effects.

Low IQ (intelligence quotient) in children refers to a measure of cognitive abilities that are below the average for their age group. IQ tests are standardized assessments designed to evaluate intellectual skills, problem-solving abilities, and reasoning.

In children, low IQ may mean developmental delays in learning basic skills, difficulty communicating, not understanding complex concepts, or needing support in making daily decisions.

Key findings of the NTP study

The researchers revealed that since its introduction in 1945, fluoride has been a cornerstone of public health efforts to reduce dental cavities.

However, a meta-analysis published in JAMA Pediatrics evaluated 74 epidemiological studies from ten countries, including India, China, and Mexico, and revealed concerning trends.

Fluoride and decline in IQ: The analysis showed that for every 1 mg/L increase in urinary fluoride, children’s IQ scores decreased by 1.63 points.

High exposure limit: Significant reductions in IQ were observed at fluoride exposure levels greater than 1.5 mg/L in drinking water or urine.

Limited data at lower levels: There was insufficient evidence to conclude whether fluoride levels at or below 0.7 mg/L – the level recommended by the US Public Health Service – have adverse effects on IQ.

Regional impact and context of India

Excessive fluoride exposure is not a new problem in India. Fluoride levels in groundwater often exceed safe limits in areas such as Haryana, Punjab and Rajasthan.

This has led to health complications such as dental and skeletal fluorosis and possible neurological impairment in children, said Dr Kadam Nagpal, head of neuroimmunology at Salubritas Medcentre.

“Excessive fluoride accumulates in teeth, bones and soft tissues, causing metabolic changes. This can affect learning and memory in children,” said Dr Nagpal.

India’s National Program for Prevention and Control of Fluorosis (NPPCF) monitors and reduces high fluoride levels in groundwater. Measures such as installing reverse osmosis (RO) plants and increasing awareness about fluoride containing products are some of the important components of this initiative.

Balancing dental health and nerve development

Fluoride is essential for preventing cavities, but frequent excessive exposure from multiple sources, such as water, toothpaste, tea and processed foods, can lead to cumulative risks.

Dr. Nagpal stressed the importance of moderation and advised parents to monitor fluoride intake. “Children should not brush more than twice a day using toothpaste in controlled amounts, especially in areas where the water has naturally high fluoride levels,” she said.

Furthermore, the findings underlined the need for nuanced public health strategies. While fluoridated water has reduced dental problems globally, it is important to ensure that overall fluoride exposure remains within safe limits.

The NTP concluded with moderate confidence that fluoride levels above 1.5 mg/L are associated with lower IQ in children. However, it found no evidence linking fluoride to cognitive decline in adults, suggesting that children’s developing brains are particularly vulnerable.

The World Health Organization’s safe limit for fluoride in drinking water is 1.5 mg/litre, and the Government of India continues efforts to ensure compliance with it.