In our last issue, The Truth About Fluoride, we traced how fluoride became embedded in public health policy. We learned that its addition to public water and toothpaste was never based on fulfilling a biological need - there was no evidence the human body needed it. Instead, industry influence shaped its adoption, rebranding chemical waste as a “public health” solution.
That history matters because it reframes how we view fluoride today. Unlike minerals the body truly needs—such as calcium, magnesium, and phosphorus—fluoride is not essential: it does not strengthen teeth, it does not build healthy bones, and it isn’t required by any organ system. Even major health organizations like the FDA, CDC, and WHO now acknowledge that fluoride provides no essential health benefit.
This raises an important question: if the body has no use for fluoride, what happens when we ingest it? In this issue, we’ll cover how fluoride is absorbed and stored in your body, why it builds up in teeth and bones, and how this quiet accumulation can lead to irreversible health consequences.
Contents
Fluoride in the Body
Why Fluoride Accumulates in Bones and Teeth
What Is Dental Fluorosis?
Stages of Dental Fluorosis
Health Effects Beyond Tooth Enamel
Protect Your Family
Absorption
When you ingest fluoride – whether from drinking water, toothpaste, or foods – your body absorbs most of it. Approximately 80–90% of ingested fluoride is rapidly absorbed through the gastrointestinal tract into the bloodstream.
Once absorbed, fluoride disperses throughout the body via the blood circulation. Unlike nutrients whose levels are tightly regulated by the body, fluoride is not subject to any homeostatic control in our blood. It goes wherever the blood flows, chemically reacting with organs and tissues as it circulates.
Retention and Accumulation
After absorption, the kidneys work to filter toxins out of the blood, but their capacity is limited when it comes to fluoride. On average, only about 50% of the fluoride an adult ingests each day is excreted in urine; the other half remains in the body, where it is free to roam and gradually accumulates as a cumulative toxin.
This retention rate is even higher in the very young. Children may retain up to 60–80% of absorbed fluoride, and infants under one year old can retain as much as 90%.
What makes fluoride’s accumulation especially concerning is that the human body has no efficient mechanism to remove stored fluoride. Once fluoride lodges in our tissues, there is no enzyme or metabolic pathway that can quickly dislodge it. Only very slow processes - such as the turnover of bone tissue or the tiny amount of fluoride released from bone and excreted by the kidneys - can reduce the body’s fluoride burden, and these processes occur over years.
For example, even after stopping fluoride intake completely, studies have found that bone fluoride levels might fall by only about 50% after 20 years. In practical terms, if you stopped ingesting fluoride today, it would take two decades for your body to eliminate just half of what has already accumulated. Each new exposure simply adds to the cumulative burden. Layer by layer, year after year, fluoride quietly embeds itself deeper into our tissues.
Why Fluoride Accumulates in Bones and Teeth
When fluoride enters the bloodstream, it doesn’t distribute evenly across all organs; instead, it gravitates toward calcium-rich tissues. Roughly 99% of the fluoride that remains in the body is ultimately stored in bones and teeth.
This is no coincidence of anatomy but rather a predictable result of chemistry. Fluorine (the elemental form of fluoride) is the most electronegative element on the periodic table, which means it strongly attracts positively charged minerals like calcium. In effect, fluoride seeks out areas where calcium is abundant and binds tightly to those calcium-rich mineral matrices. This chemistry explains why our teeth and bones become the primary storage sites for fluoride.
This selective deposition sets the stage for the earliest visible sign of excess fluoride exposure during development: dental fluorosis.
Dental fluorosis is a developmental disturbance of tooth enamel caused by excess fluoride exposure during the years when teeth are forming. It isn’t a genetic disease or random defect, but rather visible evidence that a child was exposed to too much fluoride during a critical stage of growth.
Timing Matters: The “Critical Window”
Tooth enamel forms only once, long before the teeth erupt into the mouth. This makes the timing of exposure especially important:
Baby (primary) teeth: begin forming around the 14th week of pregnancy and finish mineralizing by about age 3.
Permanent (adult) teeth: start forming at birth and continue developing under the gums until roughly age 8 (with wisdom teeth extending into the teenage years).
If fluoride intake is high during these windows - whether from water, toothpaste, mouth rinses, and other sources - the normal process of enamel formation is disrupted. The result is fluorosis: a permanent mark that indicates fluoride reached toxic levels during development.
How Healthy Enamel Forms
To appreciate what goes wrong in fluorosis, it helps to first understand how healthy enamel is formed.
During enamel formation, specialized cells called ameloblasts secrete and organize the enamel tissue. Enamel consists of tightly packed microscopic crystals of hydroxyapatite (a calcium-phosphate mineral). Mature enamel is about 96% mineral, making it the hardest tissue in the human body.
Under ideal conditions, ameloblasts lay down enamel in a precise, well-regulated sequence. Initially, they produce a protein-rich matrix and then, during the enamel maturation stage, those proteins are withdrawn and replaced with layers of densely packed calcium-phosphate crystals. The result is a dense, glass-like lattice with virtually no gaps. Healthy enamel is smooth, extremely hard, and highly resistant to wear—essentially a suit of armor designed to last a lifetime
How Excess Fluoride Disrupts This Process
When excess fluoride is present during the critical periods of enamel formation, it disrupts maturation by interfering with protein removal and mineralization. Fluoride ions replace the hydroxyl ions in the hydroxyapatite crystal lattice. This small substitution has a big impact: instead of growing smooth, tightly packed crystals, the enamel develops microscopic gaps and irregularities. The result is porous, fragile enamel that is permanently weakened.
Stages of Dental Fluorosis
The severity of dental fluorosis depends on how much fluoride a child consumed, and for how long, during tooth development. When the affected teeth finally erupt into the mouth, the damage becomes visible. Dentists generally categorize fluorosis severity as follows:
Mild fluorosis: Faint white streaks or tiny specks on the enamel.
Moderate fluorosis: Larger, chalky white patches with a rough texture.
Severe fluorosis: Distinct brown stains, pitted enamel, and areas so brittle the enamel can chip or flake away.
Under a microscope, fluorosed enamel has a chalky, porous subsurface and a mottled appearance. Macroscopically, this manifests as white opaque patches or striations (areas of subsurface hypomineralization) often accompanied by a well-mineralized but thinner outer enamel layer. In more severe cases, parts of the enamel are so weak that they flake or crumble after the tooth erupts.Enamel affected by fluorosis is permanently altered and structurally weaker than normal enamel. It is more porous, making it more prone to chipping, wearing, and decay. Its increased porosity also means it stains more easily. Public health officials sometimes dismiss mild fluorosis as “cosmetic only,” but that is a mischaracterization. Dental fluorosis is a visible warning sign of toxicity. Even the mildest white flecks indicate that fluoride reached toxic levels in the body during a critical period of tooth development; in severe cases, the damage is obvious.
Health Effects Beyond Tooth Enamel
Fluorosis marks the beginning of broader health risks from fluoride. While the most immediate effect of fluoride toxicity appears in the teeth, continued exposure and accumulation can lead to a host of other issues throughout the body. Extensive research (including animal studies, human epidemiological studies, and clinical reports) has linked chronic fluoride ingestion to problems in the bones, nervous system, endocrine system, and more. Here are a few of the documented conditions associated with long-term fluoride exposure:
Skeletal fluorosis: Fluoride accumulates in bone over time, making bones abnormally dense yet more brittle. This can cause joint stiffness, arthritis-like pain, and an increased risk of fractures.
Neurological effects: High fluoride exposure has been linked in studies to reduced IQ in children and associations with behavioral issues like ADHD and autism spectrum disorders.
Thyroid disruption: Fluoride can compete with iodine in the body and may suppress thyroid hormone production. This can contribute to fatigue, weight gain, and developmental delays in children.
These examples represent only part of fluoride’s impact. Given enough time and continued exposure, fluoride has the potential to affect virtually every organ system it comes into contact with.
Final Thoughts
Fluoride has long been framed as a “public health success,” but the evidence tells a different story. Dental fluorosis shows us, in plain sight, that excess fluoride disrupts one of the body’s most precise developmental processes. Enamel—the hardest, most resilient tissue we have—becomes porous, stained, and fragile. And if fluoride can alter enamel in this way, it’s not hard to imagine the subtler, less visible effects it may be having on bones, glands, and the brain.
Public health agencies may downplay fluorosis as merely cosmetic, but those faint white streaks are not harmless blemishes. They are warning signs—early markers that the body has been overloaded with a substance it does not need and cannot effectively remove. Fluorosis is not just about teeth; it’s a window into fluoride’s systemic impact.
The key takeaway is simple: fluoride is not essential, yet it builds up in our bodies over time. By the time fluorosis appears, fluoride has already left its mark internally. Recognizing this is the first step in protecting ourselves and our families.
Protect Your Family
The good news is that dental fluorosis is entirely preventable. If you or your child already show signs of fluorosis, take it seriously: it’s an early warning that fluoride has begun accumulating in the body. If no signs are visible, consider that good news and a window of opportunity.
Either way, the solution is the same: reduce and remove unnecessary fluoride exposure from your daily life.
Here are concrete steps you can take:
Water: Use a high-quality reverse osmosis (RO) or distillation system (with third-party testing) to remove fluoride from your tap water. Most simple pitcher or faucet filters do not eliminate fluoride. If you buy bottled water, look for brands labeled “fluoride-free” or check the water quality report.
Toothpaste: Switch to fluoride-free toothpaste, especially for children. Kids under six often swallow toothpaste, and even a pea-sized dab of 1000–1500 ppm fluoride paste is a strong dose. Avoid brightly flavored toothpaste or fancy colors that encourage kids to swallow.
Nutrition: Certain nutrients can help offset fluoride. Calcium and magnesium in the diet can compete with fluoride in teeth and bones, helping reduce its binding. Eating whole foods like raw dairy, grass-fed meats, bone broth, and organ meats provides the nutrients and fat-soluble vitamins that naturally strengthen enamel and bones.
Consistency: The biggest impact comes from eliminating fluoride at its two largest sources: your drinking water and your toothpaste. Once you cut off those exposures and stay consistent, the body can gradually begin to clear out the fluoride that has been stored.
By taking these steps, you can significantly reduce new fluoride exposure and help prevent further accumulation in your body. Each action you take limits how much additional fluoride you ingest, giving your body a chance to slowly detoxify and recover from any fluoride that’s already been stored.
Coming Next
In our next issue, we’ll take a closer look at skeletal fluorosis — examining how long-term fluoride exposure changes bone chemistry, stiffens joints, and erodes mobility. From there, we will continue tracing fluoride’s effects throughout the body.
This series is designed to give you the full picture of what fluoride does to the body, why that damage matters, and how you can protect yourself and your family. Stay tuned!