Fluoride is a natural element found in the environment in both soil and water. Most of the fluoride in the environment is spread by the weathering systems and natural events like volcanic activity. In addition, there is also the release of fluoride from fertilizers, smelting, and chemical manufacturing industries. However, the majority of people are exposed to fluoride via their drinking water. This fluoride has been added to prevent tooth decay.

Most people believe that the addition of fluoride in our municipal waters has been a major public health achievement of the past century. The people who have advocated fluoride claim that it has prevented cavities and maintained good dentition in millions of people all over the world. However, there are now some questions being asked about fluoride in our drinking waters. In fact, many communities have stopped the addition of fluoride to their municipal water supplies. Many online communities have started campaigns suggesting that fluoride may not be safe as what was once believed. In fact, fluoride may be causing more harm than good.

Why is water fluoridated?

Water fluoridation started a century ago when it was realized that the mineral could prevent cavities and staining of teeth. Many studies were published in the 50s-70s on how fluoride prevents cavities and led to the durability of teeth. However, now these studies are being questioned because it appears there were many methodological errors and none of the studies were randomized or blind.

The Debate

Proponents of fluoridation indicate that the process is cost effective and has lifelong benefits. The cost to the consumer is minuscule- but what these experts fail to mention is the adverse effects of fluoride. Opponents of fluoride insist that the impact of fluoride is much less than what is stated in older publications. Plus, today there are toothpaste and mouthwashes that contain fluoride. In addition, dental hygiene can also be maintained with brushing and regular flossing and thus fluoridation of water is not mandatory. Globally the rates of tooth decay have subsided even in areas where water is not fluoridated. Plus analysis of older studies on fluoridation indicates that the results are mixed and fraught with methodological issues. In fact, there are many studies showing that fluoridation does not decrease cavities but these studies are rarely mentioned in the media.

Neurotoxicity

Both human and animal studies show that fluoride can accumulate in the brain and lead to a wide variety of adverse effects such as the inability to learn, dementia, abnormal behavior, and diminished intelligence. Most studies suggest that even at  low doses fluoride is a neurotoxin that affects both physical and mental development. In fact, three small human studies have linked fluoride exposure to impaired brain development in the fetus. Further, newer studies seem to indicate that  fluoride may also be associated with autism, attention deficit hyperactive disorder, and other learning disabilities. In other studies, children who have been exposed to fluoride have been shown to have a marked decline in intelligence quotient compared to those who were not exposed to fluoride. These changes were more marked in those with longer exposure at a high level. Even when fluoride exposure was discontinued, the detrimental effects on intelligence did not reverse.  Scientists are now concerned that the children exposed to fluoride are at the highest risk for the learning deficits.

Fluoride appears to be causing brain damage via generation of free radicals. It is believed that these changes in the brain are irreversible. Others suggest that fluoride may be just as toxic as the heavy metals like mercury and lead in its damaging effect on the brain. Biochemical and histological analysis of animals exposed to fluoride have shown a wide variety of damage that includes the following:

• Decrease in neurotransmitter receptors (esp. nicotinic)
• Inhibition of enzyme cholinesterase
• Loss of myelin and neuronal degeneration
• Loss of receptor expression on surface of nerves
• Damage to the hippocampus and frontal cortex

Other Problems

1. High levels of fluoride consumed for long periods may lead to skeletal fluorosis. These levels are much higher than those to which the average consumer is exposed daily. Skeletal fluorosis is a progressive but not life-threatening disease in which bones increase in density and become more brittle. In mild cases, the symptoms may include pain and stiff joints. In more severe cases, the symptoms may include difficulty in moving, deformed bones and a greater risk of bone fractures.

In fact, several human studies have noted an association between fluoride and the lethal bone cancer osteosarcoma.

2. Other older studies reveal that fluoride can accumulate in high levels in the pineal gland and disrupt the sleep-wake cycle and alter the release of the hormone melatonin.

3. Kidneys have also been shown to be damaged by high levels of fluoride, leading to electrolyte disturbance in the blood stream.

4. Thyroid gland suppression is known to occur after fluoride exposure. It is believed that fluoride prevents the incorporation of iodine into the thyroid hormone.

5. Intestinal problems. High levels of fluoride can cause gastrointestinal distress and symptoms of irritable bowel syndrome.

Who should decide whether fluoride is added to water?

One of the key arguments made by people who don’t want fluoride in the water is that they should be able to choose, as individuals, if they want to consume fluoride or not. If fluoride is removed from the water, people who want it can easily access it from their toothpaste or mouthwashes. So for the local governments to fluoridate everyone’s water is not right. In deed, the anti-fluoride movement has caught on and is now urging the elected officials to do something about this old age policy with questionable benefits.

So how does one prevent fluoride toxicity?

1. Today there are many types of filtration devices that can trap fluoride.  It is important to read about these devices because there are several varieties, each of which has different functional value.

2. Some experts suggest that consuming a diet rich in antioxidants like fruits may counter the adverse effects of fluoride.

3. Never give children mouthwash or mouth rinses because there is a risk that they may swallow it.

4. Speak to your dentist what other options you have for dental hygiene and protection.

Conclusion

Most opponents of fluoride insist that the older studies are not good enough to be relied upon and we seriously need to conduct more prospective and randomized studies to assess the toxicity and benefit of fluoride. While the fluoride debate continues, the public is now demanding that they should have a choice about having fluoride in their drinking water. At the moment, no one has a choice but to take it.

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Jagtap S, Yenkie MK, Labhsetwar N, Rayalu S. Fluoride in drinking water and defluoridation of water.  Chem Rev. 2012 Apr 11;112(4):2454-66. 

Kanduti D, Sterbenk P, Artnik B. FLUORIDE: A REVIEW OF USE AND EFFECTS ON HEALTH.  Mater Sociomed. 2016 Apr;28(2):133-7.

Dharmaratne RW. Fluoride in drinking water and diet: the causative factor of chronic kidney diseases in the North Central Province of Sri Lanka.  Environ Health Prev Med. 2015 Jul;20(4):237-42. 

Perumal E, Paul V, Govindarajan V, Panneerselvam L. A brief review on experimental fluorosis.  Toxicol Lett. 2013 Nov 25;223(2):236-51.