Fluoride levels in toothpaste aren’t toxic when used as directed

A video posted to TikTok, Facebook and Instagram misleadingly suggests that the fluoride found in toothpaste is “toxic” and not “safe”, and claims it is likely to destroy an important gland in the brain.

The original TikTok account that posted the video has over 270,000 followers. Full Fact has contacted this account via their webshop but has not received a response at the time of writing.

We have written before about health claims by people with large social media followings. We have also written about misleading claims about fluoride and tap water. Misleading posts about these topics can cause anxiety and lead people to make decisions based on bad information.

Fluoride

The video says: “The majority of all toothpastes have a toxic chemical in them that destroys an important gland in your brain. This substance is known as fluoride.”

It goes on to say: “The government wants you to think that fluoride is good for you and that it’s safe. But that’s just a lie.”

Fluoride is a naturally occurring mineral that can help prevent tooth decay. It is present in commercial toothpastes and can be added to water supplies for the same purpose. It is also a common subject of false claims.

Consuming large amounts of fluoride can be dangerous. But the NHS says that reviews of the risk of fluoride in toothpaste and tap water have not shown a convincing link to any health conditions. The UK Health Security Agency says that “At the levels we permit in our water supplies, there is no evidence of [fluoride] causing any harm.”.

The NHS advises that using toothpaste containing fluoride is “one of the most effective ways of preventing tooth decay.” It also says that reviews of water fluoridation have “found that water fluoridation appears to contribute to reduced tooth decay levels and doesn't seem to be associated with any significant health risks.” 

There is “no maximum recommended daily amount of fluoride” in the UK, according to a 2019 paper from the NHS’ Specialist Pharmacy Service (SPS). In the US there is a recommended limit which is 10mg daily for adults and children over the age of eight. Meanwhile a Cochrane Review, often considered the best form of evidence for medical treatments, in the same year stated that “the probable toxic dose is around 5 mg [fluoride per kg of] body weight”. It adds that “it is recommended that a fluoride toothpaste should be kept out of the reach of young children”.

The SPS paper also outlines that there are three published cases of fluoride toxicity associated with toothpaste consumption. These were linked to people who brushed their teeth at least six, 10 and 18 times daily. The NHS recommends brushing your teeth twice daily with fluoridated toothpaste.

Pineal gland calcification

The video goes on to say: “Fluoride calcifies an important gland in your brain known as the pineal gland. This gland is responsible for many things like your circadian cycle and hormone secretion.”

The pineal gland is a small part of the brain that produces the hormone melatonin. Melatonin is a hormone that plays a central role in the circadian rhythm or cycle—the 24 hour cycle of sleep and wakefulness in humans.

The pineal gland does become somewhat calcified with age, as calcium deposits accumulate in the tissue. But fluoride’s interaction with this process is much less clear than the video makes out.

As noted in an article by fact checkers Health Feedback, claims about fluoride affecting pineal gland calcification tend to stem from the work of Dr Jennifer Luke who found that in research on a small number of human cadavers the amount of calcium in the pineal gland correlated with the amount of fluoride. 

But this doesn’t necessarily mean that fluoride caused the calcification—a separate process could cause both to accumulate in the gland. 

The effects of calcification

The video also says: “Side effects of having a calcified pineal gland include a wide range of neuronal diseases like Alzheimer's, and also disruption of melatonin and serotonin levels.”

Again, this definitive claim doesn’t fully reflect the current evidence available. 

It has been reported that some studies have found links between pineal gland calcification and Alzheimer’s dementia. Dr Luke also found lowered melatonin levels in pre-pubertal gerbils fed high-fluoride diets compared to those on low-fluoride diets. 

But animal studies are not necessarily relevant to humans, unless this is shown with further research.

A systematic review of melatonin levels and Alzheimer’s dementia found that people with the condition did seem to have lower levels of melatonin at night compared to people of the same age without the disease. Whether this is due to problems in the pineal gland or in other parts of the pathway that produces melatonin isn’t clear. 

We also don’t know whether decreased melatonin plays a role in causing Alzheimer’s, if it is the other way around, or if another factor causes both independently.

The same review notes that increased calcification has been found in people with Alzheimer’s, but again as above, whether this is a causal relationship is unclear.

An EU summary of evidence from 2012 says that human and animal research has not shown that fluoride in drinking water affects the neurodevelopment of children or that fluoride causes neurotoxicity at the relevant doses.

The information included in this article contains the latest evidence and official guidance available at the time it was written. This is not a substitute for medical advice. If you require specific medical advice please consult your GP.

Featured image courtesy of Thegreenj