Tap water is seen in this photo illustration in Washington, DC, on August 19, 2019. - A study published on August 19, 2019 links exposure to fluoridated tap water during pregnancy to lower IQ scores in infants, but several outside experts expressed concern over its methodology and questioned its findings. Fluoride has been added to community water supplies in industrial countries to prevent tooth decay since the 1950s. Very high levels of the mineral have been found to be toxic to the brain, though the concentrations seen in fluoridated tap water are generally deemed safe. (Photo by Alastair Pike / AFP)

Regulators and health experts refute false claim about toxic fluoride levels in tap water and toothpaste

Copyright AFP 2017-2020. All rights reserved.

An image purporting to show the dangers of fluoride in tap water by comparing it to the fluoride concentration in inedible toothpaste has been shared on Facebook. The claim is false; experts say that only a very high level of fluoridated tap water or toothpaste consumption is toxic.

The image was published here on Facebook on November 22, 2020.

The text reads: “1 serving of toothpaste contains 0.22mg of Fluoride. OUR POISON CONTROL AUTHORITIES TELL US: Call poison control if swallowed.

“1 glass of tap water contains 0. 21mg of Fluoride. OUR HEALTH AUTHORITES [sic] TELL US: Drink 8 glasses per day.

“Both toothpaste and tap water contain fluoride from the waste systems of the phosphate fertilizer industry.

“These chemicals (90% of which are sodium fluorosilicate and fluorosilicic acid) are classified as hazardous wastes contaminated with varius [sic] impurities and known to cause cancer, infertility, brain degradation, and bone loss”

A screenshot of the misleading Facebook post as of November 23, 2020.

However, experts say the claim is false.

Matt Hopcraft, an associate professor at the Melbourne Dental School, told AFP via email on November 24, 2020, that one would have to consume very high levels of toothpaste and tap water for the fluoride in it to be toxic.

Hopcraft explained that a toxic dose of fluoride is 5mg per kilogram of body weight, meaning that for a 70kg adult, it would amount to 350mg of fluoride.

“Tap water in Australia where it is fluoridated is generally around 1 part per million (ppm), so a 250ml glass of water would have 0.25mg fluoride. An adult would need to drink 1400 glasses to reach a toxic dose! An infant would need to drink 200 glasses,” he said.

In adult toothpaste, Hopcraft added, there is 1000-1500 ppm of fluoride, and kids toothpaste generally has around 400-500 ppm.

“So adult toothpaste will have ~0.22mg in a pea sized amount to brush teeth, and a child’s about ½ of that,” he said.

“To reach a toxic dose for a 10kg infant, they would need to eat half a tube of adult toothpaste. The toxicity warning on the label is related to that level of consumption – it’s not saying that the normal amount of toothpaste is toxic.”

Additionally, the Australian National Health and Medical Research Council stated in a Q&A on water fluoridation that it “found no evidence that community water fluoridation at current Australian levels causes human health problems”.

“The NHMRC Nutrient Reference Values for Australia and New Zealand identifies 10 milligrams per day as the upper level of fluoride intake for an average-sized adult. To meet or exceed this level of intake means drinking at least 10 litres per day of water with fluoride at current Australian levels,” the document reads.

“However, regardless of any fluoride content in the water, this is a dangerously high level of water intake and is not recommended because of the risk of water overloading, even for people such as athletes, outdoor workers, military personnel and those living in hot and humid climates, who may approach this level of consumption occasionally.”