Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: TUESDAY, June 20, 1995 TAG: 9506210003
SECTION: EXTRA PAGE: 6 EDITION: METRO
SOURCE: JANE BRODY
DATELINE: LENGTH: Long
The dental benefits of fluorides for adults as well as for children have been demonstrated over and over again amid a swirling dispute in which opponents have denounced this public health measure as a public health hazard.
Some studies in laboratory animals that were fed up to 80 times the level of fluoride normally added to water have suggested an increase in bone cancer, and Danish cryolite workers exposed to very high levels of fluoride were found to have a suspiciously high level of bladder cancers.
Proponents of fluoridation have countered that at the levels added to water supplies - from 0.7 to 1.2 parts fluoride in each million parts of water - there is no evidence of any ill effect in people who drink it all their lives. A year and a half ago, a prestigious committee of toxicologists convened by the National Research Council concluded after a thorough review of the best available evidence that ``currently allowed fluoride levels in drinking water do not pose a risk of health problems such as cancer, kidney failure or bone disease.''
The contribution to dental health made by fluorides in water has diminished in recent years, thanks to decay-inhibiting benefits from the widespread use of fluoridated toothpastes and mouth rinses, the use of fluoride supplements and the topical fluoride treatments applied by dentists to children's teeth. Indeed, there has been a growing concern in dentistry that some children are getting too much fluoride, resulting in a harmless mottling of permanent teeth called dental fluorosis.
This concern recently led the Council on Dental Therapeutics of the American Dental Association to revise its recommendations for dietary fluoride supplements for children. The council now advises that no fluoride supplement be given to infants younger than 6 months old, at which point a quarter-milligram supplement is recommended. That amount should be increased to a half milligram at the age of 3, and not until 6 should a child whose drinking water contains little or no fluoride be given a one-milligram supplement. Previously, this level of supplement was recommended for 3-year-olds.
Supplements are important because, despite the prevailing evidence of their benefit, about 40 percent of Americans do not have adequately fluoridated water supplies. Some obtain water from wells where the water may have no natural fluoridation; most live in municipalities that do not fluoridate. The nation is still far from the Public Health Service goal originally set for 1990 and now extended to the year 2000 of bringing optimally fluoridated water to 95 percent of Americans who rely on community water supplies.
There is now also a growing concern that many children who do live in fluoridated areas are not getting the benefits of this mineral because their families have switched to bottled waters that contain little or no fluoride or the households have filtration systems that inadvertently remove much or most of the fluoride along with other less desirable substances in water like lead.
Dr. William H. Tate and Dr. Jarvis T. Chan of the University of Texas at Houston's Dental Branch have analyzed bottled and filtered waters available in the Houston area. They tested bottled waters labeled drinking, purified, distilled, spring and sparkling. Of 39 products sampled, 34 had fluoride levels below 0.3 parts per million, the level at which the dental association recommends that supplements be used for children starting at 6 months of age.
Only a few - Canada Dry, S. Pellegrino and Clearly Canadian sparkling waters and Safeway-Appletree drinking water - had significant amounts of fluorides, ranging from 0.43 to 0.72 parts per million. In a separate analysis of bottled waters, Dr. Sheila McGuire of the Harvard School of Dental Medicine found that Apolinaris Naturally Sparkling Mineral Water also had a similar amount of fluoride, 0.65 parts per million.
For most of the products they tested, the Texas researchers performed two or three analyses and discovered that fluoride levels in several products dropped twofold to fourfold over the course of two years. However, Tate said in an interview, the product name and label had not changed. Presumably, though, the water source or the filtration process used by the companies had changed, resulting in reduced fluoride levels. This means that consumers cannot depend from one year to the next on a single analysis of a product's fluoride content.
Of the 16 home filtration systems the Texas team examined, six removed most or all the fluoride in the original water supply. The greatest losses were associated with systems that operated by reverse osmosis. Those that used only activated carbon, activated charcoal or bubbling ozone had little or no effect on fluoride levels.
More recently, Chan and Tate and a colleague, Cui Feng Liu, analyzed fluoride content of various milks and teas. Among the milks, which included whole, skim, buttermilk and chocolate milk, only soy milk had a meaningful amount of fluoride, 0.49 parts per million. But the teas, whether herbal, green or regular, contained considerable amounts of fluoride, several of them above the levels used in fluoridation. For example, Twinings Earl Grey tea had 2.07 parts per million; Lipton's English Breakfast, 2.17; Tetley, 3.03; Kukicha Organic Twig, 3.22; Stash English Breakfast, 3.76, and Nestea Instant Iced tea, 7.58.
In the interview, Tate said the group had also tested reconstituted juices commonly offered to children. Although the results have not yet been published, he said that in general the amount of fluoride in juices was about the same as that found in the municipal water where the product was prepared. ``Although fluoride in the various products ranged from 0.08 to 1.0 parts per million, a lot had a good level - 0.7 or 0.8 parts per million,'' he said.
Before prescribing a fluoride supplement, Tate and Chan recommend that doctors and dentists consider, in addition to the fluoride in the household water, factors like whether the baby is being breast-fed (breast milk, like cow's milk, has little fluoride whereas soy-based formulas have a considerable amount) and whether instant baby food or formula is being reconstituted with fluoridated water.
For babies over 6 months, liquid fluoride supplements can be placed on the baby's tongue or added to water or juice. But since milk impedes the absorption of fluoride, the baby should not have milk for one hour after being given the supplement.
- New York Times Syndicate
by CNB