FAMILY MEDICINE® COLUMN

By John C. Wolf, D.O.Associate Professor of Family Medicine Ohio University College of Osteopathic Medicine

HOME FILTERS REMOVE BOTH HELPFUL FLUORIDE AND HARMFUL CHEMICALS

Question: Does fluoride in drinking water benefit your teeth by direct contact with them as it is swallowed or by indirect action through the blood? Also, I use a Brita filter for my drinking water. Does this remove fluoride? And finally, does freezing fluoridated water into ice cubes change fluoride's effect?

Answer: The issue of fluoride and drinking water is an ongoing topic of heated debate in many communities, including mine (Athens, Ohio). As I'm sure you know, its use is advocated to reduce the rate of dental decay, the most prevalent infectious disease. In some low income areas, 30 to 50 percent of all children have cavities!

The Centers for Disease Control and Prevention have recommended the introduction of fluorine compounds (fluoride) into drinking water that doesn't naturally contain it to the concentration of 0.7 to 1.2 parts per million. This is a process called "fluoridation." The CDCP believes that the relatively widespread adoption of this public health measure is largely responsible for the drop in frequency of cavities in the past 20 years. But as I'm sure that you have surmised from the controversy, fluoride can also be harmful. Levels over 4.0 parts per million increases the rate of bone cancer and other ailments.

Dental decay occurs when three common mouth conditions coexist. They are: 1) susceptible dental enamel, 2) a significant population of streptococcus mutans bacteria, and 3) suitable carbohydrates (sugar) for the bacteria to convert into acids that eat away the enamel. Fluoride improves the quality of enamel and makes it much harder. Therefore, the enamel becomes more impervious to the acid, and decay is less likely.
The opponents of fluoride in water argue that brushing and other methods of fluorine application can be used to reduce the number of cavities in children. The rest of us should not be exposed to the risk of having excessive amounts of it by its inclusion in drinking water. The case for fluoridation is obvious and doesn't need repeating here. And fluoride in drinking water works both by direct contact with teeth as well as systemically. Some that is swallowed eventually is secreted into saliva where it directly contacts and strengthens the tooth enamel.

Now to your question about your Brita filter. The Brita filter, like many similar products, uses charcoal to remove chemically active contaminants from water. These units are about 81 percent effective in removing fluoride. Other water purification products such as reverse osmosis filters and distillation also remove fluoride and other water contaminants. These methods are even a bit more effective than charcoal filtration. Chilling or freezing your drinking water doesn't appreciably change the amount of fluoride it contains or its effect.

So you should be aware that you and your family are not getting substantial amounts of flouride from your drinking water because of the charcoal filter. That is of some concern for children, who normally get the most cavities. However, if you choose to continue to use the filter, your family can reduce the risk of cavities by the conscientious use of fluoride-containing toothpaste and regular professional applications of fluoride. In some cases, your dentist might also recommend prescription flouride tablets.

"Family Medicine" is a weekly column.

To submit questions, write to John C. Wolf, D.O., at Post Office Box 110, Athens, Ohio 45701.

Past columns are available online at http://www.FamilyMedicineNews.org.