File this one under “conspiracy theories”. I had a discussion today with a person on facebook about fluoride. This person made that fluoride in the drinking water causes brittle bones. It’s true that fluoride can replace calcium in bones and weaken them. But that grain of truth doesn’t mean that the rest of the claim is valid. We see this a lot. A kernel of truth blown all out of proportion into a huge lie. The average person has between 500-1000 mg of fluoride in their bones per kilogram of bone mass. That’s NORMAL. A preclinical case of skeletal fluorisis is between 3500 and 5500 mgF/kg of bone. In this case, there no actual symptoms and the effect is barely detectable in radioscans. Clinical Phase 1, resulting in stiffness, joint pain, etc. is between 6000-7000 mgF/kg. In other words between 6 and 14 times what is normal.
The EPA regulates fluoride in water to a max of 4 mg/liter. Though many local areas have a stricter limit of 2 mg/L. Now, bone is about 15-20% of your mass (roughly). So a 200 pound male, has a skeletal mass of about 30 pounds or roughly 15 kilos (yeah, that’s loose, but it’s close enough for this discussion). And the intake of fluoride in the human body is roughly 50%.
So, to get 15 kilos of bone from 1000mgF/kg to 6000mgF/kg would require 5000 mgF/kg * 15 kg / 2mg/L / 50% = 75,000 liters of water.
The EPA suggests that a modern human in the US drinks about 2 liters of water per day. Assuming that you live in a city and drink fluoride infused water up to two liters per day, then you will get the max dose in about 102 years. Drink significantly more water than that, and you’re more in danger of dying from water overdose than from Fluoride. This all assumes that every mg of fluoride absorbed stays in the human body indefinitely, which is not the case. That last link shows that the fluoride concentration in urine increases linearly with the fluoride concentration in the blood. Finally, let me quote from this paper
Fluoride is the only extensively clinically proven means of reducing dental caries. Despite a large body of epidemiological data on the effectiveness of fluoride, delivered in the form of dentifrices, mouthrinses, drinking water, etc., the precise mode of action of fluoride is not completely understood.
No, we don’t know how it works (or maybe we do, that paper is from 1991), but it does work… and it doesn’t cause bone disease. So drink tap water. It helps.
