Fluoride - Friend or Foe ?

Most of us were taught that fluoride is our friend and helps to prevent cavities and strengthen bones. But toxicologists rate fluoride as more poisonous than lead and almost as poisonous as arsenic. So how can it be our friend?

The supporting argument is that fluoride in small amounts is beneficial and only in large amounts is it harmful. Well, this is true of many beneficial minerals, but what does science show us about the benefits and toxicity of fluoride? The evidence suggests that fluoride has little if any beneficial effects and even at relatively low concentrations has a variety of serious harmful effects. Yes, topical application of fluoride at high concentration will kill bacteria in your mouth and that may possibly confer some benefit against tooth decay. But at what cost to your health?


Because of it's poisonous effects, fluoride is a common ingredient in many pesticides. That should tell us something. Too much fluoride can cause obvious bad symptoms, the most common of which is dental fluorosis. The rates of dental fluorosis have increased dramatically in the U.S. over the last several decades. According to the Centers for Disease Control, dental fluorosis now impacts 32% of American children, whereas in the 1940s, dental fluorosis rates in fluoridated areas averaged 10%. But that's not the only potential problem caused by too much fluoride. Fluoride apparently interferes with proper thyroid function and iodine metabolism in the body. It may be a factor in the recent epidemic of hypothyroidism, since low thyroid function is related to problems with iodine metabolism. Also, studies of fluoride levels in drinking water show a clear inverse relationship with intelligence in children. Apparently, higher levels of fluoride reduce the intelligence of children by negatively affecting brain development.

So many people were sold on the idea that fluoride is beneficial in preventing tooth decay that it has been added to public water supplies in much of the U.S.A. for many years, typically at concentrations of around one part per million (ppm). But is this really beneficial? In Europe, fluoride has been banned from water supplies in most areas, and yet levels of tooth decay are not higher as a result. There is little evidence to show that adding fluoride to drinking water prevents tooth decay. Unfortunately, adding fluoride to drinking water increases our exposure not only directly by drinking the water, but indirectly by consuming food and beverages that were processed with fluoridated water. Considering that we also get fluoride from pesticides in our food, from toothpaste, from non-stick cookware, household pesticide sprays, and from some pharmaceutical drugs, that can add up to quite a bit of fluoride intake. This increased fluoride exposure may be enough to explain the large increase in dental fluorosis and to raise suspicion in the large increase in hypothyroidism.

We were also taught that fluoride helps to strengthen our bones. This may possibly be true in very small amounts, but even this possibility is controversial. Animal studies show either no effect or a negative effect of fluoride on bone strength. But at the typical exposures today, fluoride may contribute significantly to bone brittleness and easier bone breakage.

If you drink fluoridated water, it typically has about one ppm or one milligram per liter (mg/l) of fluoride. That means if you drink two liters per day (about two quarts per day) you get two milligrams (mg) of fluoride per day just from your water alone.

The U.S. Institute of Medicine, Food and Nutrition Board, has set the Adequate Intake (AI) per day for fluoride at 4 mg for men and 3 mg for women (ages 14 and over). They list the "Tolerable Upper Intake Levels (UL)" at 10 mg per day. Unfortunately, it appears that this recommendation was heavily influenced by pro-fluoridation proponents and is much too high. The UL should probably be more like 2 to 4 mg per day and ideally we should try to keep total fluoride intake to less than one mg per day to minimize risk of harmful effects.

There are a few foods that have higher amounts of fluoride and should be consumed in modest amounts, including tea, wine, and raisins. Natural ground water can also be high in fluoride in some areas and may need to be tested before use as a drinking water supply.

Here's what the USDA reports for the concentration of fluoride (ppm):
1.15 Tea, green, brewed (23 samples)
2.72 Tea, green, decaffeinated, brewed (10 samples)
3.73 Tea, black, brewed, regular, all (63 samples)
1.05 Wine, red (14 samples)
2.02 Wine, white (17 samples)
2.13 Grape juice, white (12 samples)
2.34 Raisins (1 sample)

Note that 1 ppm = 1 mg/l = 0.24 mg per 8 ounce cup

The Linus Pauling Institute reports the following measurements of fluoride in brewed tea (ppm):
0.6-1.0 Oolong
1.2-1.7 Green
1.0-1.9 Black
2.2-7.3 Brick tea

The amount of fluoride varies by the age of the tea leaf. The newest buds have the least and the oldest leaves have the most. That means white teas made from the buds have the lowest fluoride and high quality teas made from younger leaves will have less than low quality teas and brick teas made from older leaves.

Organic teas may also tend to have less fluoride. The Weston A Price Foundation reported the following concentrations of fluoride (ppm):
0.86 Tap water
0.62 Filtered water
0.94 Organic black tea (made with filtered water)
0.90 Kombucha (made with organic black tea)

Regarding prevention of tooth decay, Weston Price found that people eating healthy native diets had little tooth decay. But when these same people began eating refined flour and sugar, tooth decay became rampant. The moral is that proper diet and hygiene will prevent tooth decay. Added fluoride is just another poison that we don't need in our water and diet.