From the Guidelines
Fluoride in drinking water has been associated with adverse effects, including cardiac complications, neurological development issues, and skeletal fluorosis, as documented in recent studies, such as the 2022 espen micronutrient guideline published in Clinical Nutrition 1. The potential negative effects of fluoride in water are a concern, with some studies suggesting a link between high levels of fluoride and reduced intelligence in children, as well as an increased prevalence of cardiac complications in residents of fluorosis endemic areas 1. Some key points to consider include:
- The espen micronutrient guideline notes that fluoride can be provided in enteral nutrition (EN) at doses of up to about 3 mg/day, but the need for adding fluoride to parenteral nutrition (PN) is debated 1.
- An increased prevalence of cardiac complications has been observed in residents of fluorosis endemic areas chronically exposed to fluoride, and fluoride might also have an impact on children's neurological development, with greater exposure to high levels of fluoride in water significantly associated with reduced levels of intelligence in children 1.
- Poisoning from fluoride can occur through ingestion of fluoride-containing products or elevated levels of fluoride in groundwater, resulting in chronic fluoride toxicity (fluorosis) 1.
- There is no established treatment for skeletal fluorosis, but calcium and vitamin D supplementation might mineralize or prevent excessive osteoid production, and oral calcium can diminish bone resorption 1. It's essential to weigh these potential risks against the benefits of community water fluoridation programs, which are still considered safe and effective for preventing tooth decay at recommended levels by organizations such as the CDC and WHO.
From the Research
Adverse Effects of Fluoride in Drinking Water
The following are some of the sources documenting adverse effects of fluoride in drinking water:
- Dental fluorosis: a condition caused by excessive intake of fluoride during tooth development, leading to discoloration and pitting of the teeth 2, 3, 4, 5
- Skeletal fluorosis: a condition caused by excessive intake of fluoride over a long period, leading to pain and damage to the bones and joints 3, 4, 5
- Reduction in IQ scores in children: some studies have found an association between high levels of fluoride exposure and lower IQ scores in children 2, 6
- Thyroid dysfunction: some evidence suggests that high levels of fluoride exposure may be associated with thyroid dysfunction 2
- Kidney dysfunction: some evidence suggests that high levels of fluoride exposure may be associated with kidney dysfunction 2
- Neurodevelopmental and cognitive effects: some studies have found an association between fluoride exposure and neurodevelopmental and cognitive effects in children, including attention deficit hyperactivity disorder (ADHD) and other cognitive impairments 6
Studies on Fluoride Exposure
Several studies have investigated the adverse effects of fluoride in drinking water, including:
- A systematic review of epidemiological and toxicological evidence on health effects of fluoride in drinking water, which found strong evidence for dental fluorosis and moderate evidence for reduction in IQ scores in children 2
- A study on recommendations for fluoride limits in drinking water based on estimated daily fluoride intake in the Upper East Region, Ghana, which found that the maximum concentration of fluoride in drinking water for children under 6-8 years should be 0.6 mg F(-) L(-1) 3
- A study on fluoride's effects on the formation of teeth and bones, and the influence of genetics, which found that excessive systemic exposure to fluorides can lead to disturbances of bone homeostasis and enamel development 4
- A systematic review of the human, experimental animal, and mechanistic literature to evaluate the extent and quality of the evidence linking fluoride exposure to neurodevelopmental and cognitive effects in humans, which found moderate confidence that higher estimated fluoride exposures are consistently associated with lower IQ in children 6
- A case report on skeletal and dental fluorosis, which found that two individuals who ingested high amounts of fluoride in water over a long period of time developed severe degrees of dental fluorosis, hyper-sensitivity of teeth, and skeletal fluorosis 5