Cleaner sources of water may be depriving dental patients of necessary fluoride content

Cynthia R. Biron, RDH

In search of safe, good-tasting drinking water, Americans are buying bottled water and/or installing water-filtering systems in their homes. While the bottled or filtered water they drink may be free from harmful chemicals and microorganisms, it also may have insufficient amounts of fluoride. We must inform our patients that some water-filtering systems remove fluoride from water, and many brands of bottled water do not contain enough fluoride, if any at all. A few contain too much fluoride. Accurate fluoride supplementation is difficult to ascertain when children are drinking mainly bottled water.

We may want to remove the following from our drinking water:

- Microorganisms. Water contains different types and levels of microorganisms - some are harmless while others, especially in sufficient numbers, are harmful. Chlorination can remove most harmful microorganisms, except the parasite known as Giardia lamblia. This parasite causes Giardiasis. The giardia cyst attaches to the intestinal wall and causes diarrhea, cramping, gas, dehydration, and loss of appetite. Giardia are found in lakes and mountain streams. Fifteen percent of those infected contract the parasite from drinking lake or mountain stream water.

Others contract the parasite from person to person contact. After changing infant diapers, hands must be thoroughly washed. Children tend to forget to wash their hands after urinating and defecating. Contaminated hands touch other surfaces and individuals, spreading the parasite from one person to another. Giardia can be removed from water by boiling the water, adding iodine tablets to water, or filtering water.

- Lead. Water, by itself, contains very little lead. The water can become contaminated in the water distribution system and/or pipes. Lead pipes, brass faucets, and lead solder are the sources of lead contamination in water. As of 1986, lead pipes and lead solder were banned. Pipes now are polyvinyl (PVC) and joined with nontoxic cements. All of the plumbing that still exists in buildings built prior to 1986 may contain lead solder or pipes.

Soft or acidic water tends to be corrosive and is more likely to corrode the plumbing, leaching out the lead. You can avoid lead intake in water by drinking or cooking with cold water from the tap, (hot water from the tap dissolves lead from pipes), running water for a while before drinking it, and installing calcite filters, ion-exchange filters, or reverse osmosis filters.

- Nitrates. Nitrates occur naturally or enter water through runoff from septic systems, fertilizers, and animal wastes. Nitrates can covert to nitrites, which can combine with some hemoglobin in blood and form methemoglobin that cannot transport oxygen. The condition can be quite serious in the unborn fetus, infants, and children.

- Sulfate. Sulfate occurs naturally in water and high concentrations of it can have a laxative effect, especially in individuals who are not used to high concentrations of sulfates.

- Organic chemicals. Pesticides and industrial chemicals or products can contaminate water if accidental spills occur. All municipalities are required to monitor organic chemicals according to the Safe Drinking Water Act.

- Radon. The radioactive gas known as radon is a decay product of uranium. The odorless, colorless, and tasteless gas usually enters homes through cracks in the foundations. High levels of radon in the air suggests a strong possibility that radon also may be present in the household water supply. The Environmental Protection Agency (EPA) estimates that some 8 million people may have high levels of radon in their water supplies. More commonly, it occurs in households supplied by private wells and small community water systems. Granular activated carbon units and home aerators are installed to reduce radon levels.

What should stay in the water?

Some minerals such as calcium, magnesium, and iron are beneficial in safe amounts. But overall, drinking water does not serve as a significant source of the bodily requirements of such minerals. Food intake and vitamin/mineral supplements provide Americans with necessary vitamins and minerals.

What dental professionals want to see remain in water is fluoride. The fluoride ion may occur naturally in water or may be added to the community water supply. Reverse-osmosis filtering systems can remove almost all of the fluoride from the household water supply. Bottled water may not contain any or enough fluoride to provide a significant supply to children for prevention of tooth decay.

There has been a 50 percent decline in dental decay in the past 20 years. The decline occurred for the most part in areas where water fluoridation has been in effect. Forty percent of tap water in this country still remains unfluoridated. Opponents to water fluoridation have fought to keep fluoride out of community water supplies. They claim it causes various diseases (a recent study showed that a rare bone cancer developed in male rats who were given high levels of sodium fluoride). For some reason, the female rats were unaffected by the same treatment.

The EPA sets the maximum allowable levels of sodium fluoride in drinking water - the amount that should occur either naturally or as an additive. The safe maximum allowable amount is way up at 4ppm. The recommended maximum allowable level of the EPA is 2ppm. When fluoride is added to a community water supply it is at a very safe level of 1ppm. That is the level that will provide beneficial effects to the population without having any toxic effects.

All of the tests that have occurred with animals in laboratory research have been with very high doses of sodium fluoride. One could not possibly drink enough 1ppm fluoridated water within a time frame of toxicity to cause ill effects. Both the American Dental Association and the American Medical Association promote fluoridation. But now that household water supplies often are filtered, and bottled water frequently used for drinking water, some children will receive only 8 percent of the fluoride they would have been receiving if bottled water was not available.

Types of bottled water

While the EPA regulates public water systems, the Food and Drug Administration (FDA) regulates bottled water. The FDA regards bottled water as "all water which is sealed in bottles, packages, or other containers and offered for sale for human consumption" under the Code of Federal Regulations (21 CFR 129). This includes all of the following types of bottled water:

- Nonsparkling or Still - This is any bottled water without carbonation. (Constitutes 90 percent of the bottled water consumed in the U.S.).

- Sparkling water - bottled water that is carbonated with carbon dioxide. The carbon dioxide may be added to the water and termed "sparkling." Some springs already have a high amount of carbon dioxide that usually escapes as the water reaches the surface, but if it is recaptured during the bottling process, it is considered "naturally sparkling."

- Distilled water - Distillation of water removes naturally occurring minerals and dissolved solids to a level of 10 parts total dissolved solids for each million parts of water. Individuals on sodium-restricted water may be advised to drink distilled water.

- Mineral water - This is water that contains minerals.

- Natural mineral water - This is mineral water that comes from a spring or well and is not altered in the bottling process. It contains at least 500ppm total dissolved solids. Some mineral waters may contain high levels of sodium and fluoride. All water with the exception of distilled water has some naturally occurring minerals.

- Spring water - It comes from underground formation and flows naturally to the earth`s surface. The underground springs may be tapped before they reach the surface of the earth and therefore be free from ground surface contamination.

- Purified water - This is distilled, deionized, filtered by reverse osmosis, and meets the established definition of purified water in the 21st Edition of the United States Pharmacopeia.

Fluoride content in bottled water

In a recent study, 24 bottled waters were tested to determine fluoride ion concentration and the results showed a range of 0.10ppm to 1.25ppm. Multiple testing did not demonstrate a variation in amount of fluoride in each brand of bottled water. None of the brands tested had fluoride concentrations indicated on the labels. So it is not possible for consumers to know whether their children are receiving an optimum level of fluoride or too much fluoride if taken concommitantly with fluoride supplements.

Ten of the 24 bottles of water tested contained significant concentrations of fluoride, that is, greater than 0.30 ppm. One brand, Ramlosa Sparkling Mineral Water, had a fluoride concentration of 1.25ppm.

No trends on concentration levels were noticed. For the most part, concentration levels could be expected to cause partial caries inhibition if consumed by children under 3 years of age. Fluoride binds to glass, therefore some of the water sold in glass containers had a higher concentration of fluoride than other brands. The amount of fluoride a child receives through food, water, and fluoride supplements must be accurately determined so as to prevent tooth decay and avoid dental fluorosis.

If the family household has a reverse osmosis filtering system, fluoride supplements should be administered to the children who live there. Most people with such an extensive water filtration system would not be as likely to purchase bottled water for drinking and cooking. In households where fluoride is naturally occurring or added to the water supply, a simple activated charcoal filter system will not remove fluoride. The range of fluoride in such a system will most likely be 0.7ppm. to 1.2ppm. Fluoride supplements should not be given to children who consume such levels of fluoride in drinking water.

If we do not know how much fluoride is in our drinking water, we cannot determine a child`s intake of fluoride. Researchers believe that bottled water eventually will lead to an increase in tooth decay for the population of bottled water drinkers. We need to inform our patients about the need to make proper choices for their children. Babies between the ages of two weeks to two years who are breast fed and drinking bottled water probably are not receiving adequate systemic fluoride. Their intake is thought to be less than 0.3ppm. The Journal of Pedodontics lists the brand names of the 24 types of bottled water and their fluoride contents (see Figure 2).

Is bottled water safer?

Bottled water may not be healthier or safer than tap water. The public water is disinfected with chlorine, which has a strong taste, making it taste less healthy than bottled water. Bottled water is disinfected with ozone, which is a high-strength oxygen and a strong oxidant as is chlorine, but without the chlorine taste. Chlorine has a long-term limited effect. Ozone has a limited time effect.

Bottled water definitely tastes better than tap water, but that does not mean that it is safer than tap water. Microorganisms, nitrates, lead, mercury, and pesticides may not have any smell or taste, yet still be at harmful levels. The different taste of bottled water often is a result of the processing and added carbon dioxide and minerals, not the removal of the aforementioned harmful ingredients. So while we may enjoy drinking bottled water more than tap water, it is not necessarily better for us.

What is beneficial is the increase in water consumption. The eight glasses a day recommendation should not be underestimated. Flushing the system by drinking water helps remove toxins from the body and improves kidney and other bodily functions.

Let`s get the fluoride to the children and the adults, (who also benefit from fluoride for their teeth and bones). Let us get the clean, safe water to drink by researching bottled water, filtering systems, and the public water in our own communities. Educating our patients about water is one more contribution we can make toward the overall health of our patients.

References

1. McGuire S. Fluoride content of bottled water. N Engl J Med. 1989 Sep 21;321(12): 836-837.

2. Iadarola P. Fluoride and bottled water. JAMA 1986 Nov;113(5): 724.

3. Stannard J. et al. Fluoride content of some bottled waters and recommendations for fluoride supplementation. J Pedod. 1990; 14(2): 103-107.

4. Tate WH, et al. Fluoride concentrations in bottled and filtered waters. Gen Dent. 1994 Jul; 42(4):362-366.

5.E.P.A. Lead in drinking water: Should you be concerned? Environmental Protection Agency, Public Information center, Waterside Mall, 410 M St., Washington D. C.

6. The Pollutants that Matter Most: Lead, Radon, Nitrate. Consumer Reports, p. 30-32, January 1990.

7. Woodard J, et al. Buying bottled water. Virginia Cooperative Extension, Publication Number 356-486, October 1996

Cynthia R. Biron, RDH, is chair of the dental hygiene program at the Tallahassee Community College. She is also a certified emergency medical technician.