During an interview on the podcast The Joe Rogan Experience, American rapper Kanye West claimed that fluoride in toothpaste “blocks your pineal gland”. Although this interview dates back to October 2020, video clips of West making this claim, like this one, went viral on Facebook around the end of August 2022.Fluoride is a naturally-occurring mineral that is constantly released from rocks into the soil, water, and air. It is also the key ingredient to one of the greatest public health achievements in the U.S., namely water fluoridation. The U.S. Centers for Disease Control and Prevention stated that “As of 2016, more than 200 million people, or nearly 3 in 4 Americans who use public water supplies, drank water with enough fluoride to prevent tooth decay”.

A report by the UK Government, published in March 2022, found that water fluoridation “can significantly reduce tooth extractions and cavities among children and young people” and that these benefits become much more evident in more deprived areas of the country:

“Children and young people in areas in England with higher fluoride concentrations were up to 63% less likely to be admitted to hospital for tooth extractions due to decay than those in areas with low fluoride concentrations. The difference was greatest in the most deprived areas as children and young people in these areas benefited the most from fluoridation.”

From this information, we can see that fluoride has provided significant public health benefit by reducing pain and suffering from tooth decay. Fluoride’s ability to fight tooth decay has also made it a common ingredient in toothpaste. The American Academy of Pediatrics and the American Association of Pediatric Dentistry recommend that children use fluoride-containing toothpaste.

Claims that fluoride in toothpaste is harmful aren’t new. Health Feedback previously reviewed the claim that fluoride in toothpaste is a neurotoxin and found it to be inaccurate. West was repeating a persistent claim about the adverse effects of fluoride on the pineal gland. Others, such as Christiane Northrup, a physician who has spread anti-vaccine misinformation, also made the same claim in the past.

As we will explain below, West’s claim that fluoride in toothpaste harms the pineal gland is lacking in evidence.

The pineal gland’s critical role in maintaining our body’s internal clock

The pineal gland is a tiny, pea-shaped gland in the brain. Its main function is to secrete the hormone melatonin (not to be confused with melanin, which is a substance responsible for skin and hair color). The amount of melatonin it secretes is regulated by the amount of light received through our eyes.

Peak levels of melatonin in the blood occur at night, with at least ten times more melatonin than during daytime. In this way, the level of melatonin in the blood helps our body to maintain an internal clock, also known as the circadian rhythm. The circadian rhythm regulates various biological processes that fluctuate with the time of day, such as the sleep/wake cycle, body temperature, and digestion.

Some studies reported findings suggesting that melatonin also has a role in delaying sexual maturation (puberty). For example, scientists have observed that the decrease in serum melatonin correlates with the beginning of puberty^[1] and a small study in Italy reported how a lower melatonin level was correlated with more advanced puberty^[2]. However, correlation alone doesn’t prove causation, and at the moment there isn’t sufficient evidence to indicate that melatonin influences puberty.

The pineal gland tends to accumulate calcium over time (calcification). Exactly why this occurs is unclear, but it is a normal, well-known process that has already been reported in studies dating back to the seventies and even autopsy specimens from hundreds of years ago^[3]. The Cleveland Clinic states that “Calcification of the pineal gland is quite common. In fact, it’s so common that healthcare providers often use a calcified pineal gland as a landmark on x-rays to help identify different structures of the brain”.

Calcification of the pineal gland tends to increase with age^[4-6], while melatonin levels decrease with age^[7-8]. The amount of calcification relative to the total size of a person’s pineal gland correlates to the amount of melatonin that the pineal gland produces^[9], suggesting that calcification can affect melatonin production by the gland.

Because of fluoride’s chemical affinity for calcium—which is also what makes fluoride effective at preventing tooth decay—one of the key questions regarding fluoride’s potential effect on the human pineal gland is whether it could speed up calcification. If calcification does lead to reduced melatonin levels, this could potentially affect puberty and other biological processes.

Insufficient evidence to support the claim that toothpaste fluoride negatively affects the pineal gland and melatonin levels

Meedan’s Health Desk, a resource that provides explainers by in-house scientists for science questions, addressed the question of the impact of toothpaste fluoride on melatonin levels, stating that:

“Contrary to some online claims, at this time there is no data to suggest that toothpaste is impacting the small organ in our brain that’s responsible for making melatonin. Topical fluoride treatment is critical for preventing tooth decay and subsequent infections”.

As we can see from these articles by The Truth About Fluoride and Fluoride Free Australia—both of which advocate against fluoridation on the basis that it causes harm—the claim that fluoride can interfere with pineal gland function is commonly associated with research by Jennifer Luke, who published her PhD dissertation and a study in the journal Caries Research on this topic.

In her 1997 dissertation, submitted to the University of Surrey, Luke reported that gerbils fed with a high-fluoride diet produced significantly less melatonin than those on a low-fluoride diet and sexual maturation occurred earlier in female gerbils on a high-fluoride diet.

In a 2001 study, Luke reported that in 11 aged human cadavers, which were 82 years old on average, the pineal gland had accumulated as much fluoride as teeth, and that the level of pineal fluoride was positively correlated with the level of pineal calcium^[10]. In other words, the greater the level of calcium in the pineal gland, the more fluoride was present in the gland. As we explained earlier, fluoride has a high affinity for calcium, therefore this finding is expected.

Based on her findings, Luke hypothesized that fluoride could also accumulate in children’s pineal glands, because calcification of the gland in children was already reported by other scientists, and further postulated whether this could affect pineal metabolism.

However, there is a dearth of clinical evidence for the claim that fluoride harms the pineal gland in people, and Luke’s research didn’t show fluoride affecting the human pineal gland.

In its 2006 scientific review of the U.S. Environmental Protection Agency’s standards for fluoride in drinking water^[11], the National Research Council concluded that:

“Whether fluoride exposure causes decreased nocturnal melatonin production or altered circadian rhythm of melatonin production in humans has not been investigated. As described above, fluoride is likely to cause decreased melatonin production and to have other effects on normal pineal function, which in turn could contribute to a variety of effects in humans. Actual effects in any individual depend on age, sex, and probably other factors, although at present the mechanisms are not fully understood.” [emphasis added]

A more recent study published in 2019, led by researchers at the Icahn School of Medicine at Mount Sinai, used data from the National Health and Nutrition Examination survey to examine whether fluoride in the water could affect sleep regulation in teenagers^[12]. Since melatonin regulates the sleep/wake cycle, examining sleep regulation provides a proxy measure for the effect of water fluoride on melatonin.

The researchers reported an association between greater fluoride levels in the water and changes in sleep cycle and sleep behavior. However, an association by itself isn’t sufficient evidence of a cause-effect relationship.

The study also had several important limitations, as the researchers acknowledged. One limitation was that it relied on self-reports of sleep behavior, which could be affected by inaccurate memory recall. Another limitation was that the study population comprised older teenagers, “who may be prone to sleep disruptions for various reasons, including playing video games, studying, working at jobs or having social influences, for example”. The researchers called for more prospective studies to study this question.

In summary, there is insufficient evidence for the claim that the amount of fluoride present in toothpaste harms the pineal gland in humans, as West and others claimed. West is confusing a hypothesis which hasn’t yet been validated with a confirmed theory. The evidence we do have at the moment, which is limited, hasn’t shown that fluoride harms the pineal gland in people.

What little studies we have on the subject have largely been conducted in animals, not people. Furthermore, it’s unclear how the amount of fluoride used in these animal studies would relate to the level of fluoride used in toothpaste. As such, our current understanding about this subject remains incomplete and uncertain. More research is required to better understand how fluoride could affect the pineal gland in people.

REFERENCES

1 – Reiter RJ (2009) Melatonin and human reproduction. Annals of Medicine.

2 – Salti et al. (2000) Nocturnal Melatonin Patterns in Children. Journal of Clinical Endocrinology & Metabolism.

3 – Adeloye and Felson (1974) Incidence of normal pineal gland calcification in skull roentgenograms of Black and White Americans. American Journal of Roentgenology, Radium Therapy, and Nuclear Medicine.

4 – Doyle and Anderson (2006) Physiologic Calcification of the Pineal Gland in Children on Computed Tomography: Prevalence, Observer Reliability and Association with Choroid Plexus Calcification. Academic Radiology.

Mohammed et al. (2016) Pineal Gland Calcification in Kurdistan: A Cross-Sectional Study of 480 Roentgenograms. PLOS One.

Whitehead et al. (2015) Physiologic Pineal Region, Choroid Plexus, and Dural Calcifications in the First Decade of Life. American Journal of Neuroradiology.

Bojkowski and Arendt. (1990) ??Factors influencing urinary 6-sulphatoxymelatonin, a major melatonin metabolite, in normal human subjects. Clinical Endocrinology.

Giménez et al. (2022) Melatonin as an Anti-Aging Therapy for Age-Related Cardiovascular and Neurodegenerative Diseases. Frontiers in Aging Neuroscience.

Kunz et al. (1999) A New Concept for Melatonin Deficit: On Pineal Calcification and Melatonin Excretion. Neuropsycopharmacology.

Luke J. (2001) Fluoride Deposition in the Aged Human Pineal Gland. Caries Research.

National Research Council. (2006) Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. The National Academies Press.

Malin et al. (2019) Fluoride exposure and sleep patterns among older adolescents in the United States: a cross-sectional study of NHANES 2015–2016. Environmental Health.