CHART 3 Decayed, Missing & Filled Teeth Per Adult (FLUORIDE & NON-FLUORIDE COMMUNITIES) 16 MISSING TEETH PER PERSON CHART 4 Missing Teeth Per Adult (FLUORIDE AND NON-FLUORIDE COMMUNITIES) 12 20-24 BOULDER (NO FLUORIDE) COLORADO SPRINGS 16 12 - 8 + 25-29 30-34 35-39 40-44 The difference in the prevalence of tooth decay greatly influences the number of teeth lost. This is demonstrated in chart 4, showing that adults of Colorado Springs have lost only about one-third as many teeth as residents of Boulder. The evidence presented in these four charts exemplifies the vast amount of scientific data which demonstrate the dental benefits accruing to persons who have ingested fluoride in their drinking water throughout life. In short, the value of water fluoridation can be simply stated: It prevents tooth decay among children by as much as two-thirds. It cuts down tooth loss in adults by an even greater amount. Now, Mr. Chairman, I should like to talk about our research on the safety of the procedure. Naturally, at the time the fluoridation of water supplies was first considered, the safety of the procedure was of vital concern. Let me cite some of the more important studies and observations which have demonstrated conclusively that the addition of small amounts of fluoride to a water supply is safe. First of all, as I have noted, fluoride is universally present in the earth's soil, its plants and its animals, including man, and in all water supplies which come in contact with the earth's surface. CHART 5 Towns Using Naturally Fluoridated Water ( 0.7 PPM OR MORE OF FLUORIDE) This map (chart 5) will give you some idea of the number of communities which normally have at least 0.7 parts per million or more of fluoride in their drinking water. The dots on the map represent some 1,200 communities whose people, about 4 million of them, have been consuming water with close to or above the recommended concentration of fluoride for many years. An additional 60 million have been drinking water with some fluoride-less than ideal-but still measurable. The consumption of fluoride-bearing water was never, therefore, uncommon. None of us has ever had a completely fluoride-free diet. The majority of foods found on the average American table contain from 0.2 to 0.3 parts per million of fluoride. Seafoods and tea are quite high in fluoride content. Exclusive of drinking water, the average diet in the United States provides a total intake of 0.2 to 0.3 milligram of fluoride daily. It is thus clear that all of us consume a certain amount of fluoride every day. The addition of fluoride to a fluoride-deficient water merely adds a controlled and very minute amount to our daily intake. Another important point is that the dissolved particles of fluoride in a water supply are identical whether they come from fluoridebearing soil, subterranean rock, or from a fluoride compound added mechanically in a water plant. All fluoride ions, regardless of source, are the same chemically, and in their physiological action. This is a basic and elementary fact which has been demonstrated in the laboratory, and in studies on both animals and humans. Among our principal concerns with the safety of fluoridation is the ability of the body to handle at all times small amounts of fluoride by assimilation or excretion. The kidney is the organ primarily involved in the elimination of ingested fluorides. In general, a person will excrete in the urine almost all of the fluoride ingested. Since this is a key point in any consideration of the safety of fluoridation, Dr. Zipkin of our National Institute of Dental Research will discuss in more detail the efficient manner in which the body handles fluorides. Dr. Zipkin? Dr. ZIPKIN. Mr. Chairman and members of the committee: I should like to comment very briefly on several specific points: (1) The fluoride content of foods; (2) the effect of fluoride on bone fractures and bone development; (3) the urinary excretion of fluoride, and (4) the effect of low-level fluoride ingestion in animals. To help make these points clear, I have prepared several charts which are attached to my prepared statement. These are numbered serially, and I shall refer to them from time to time. The fluoride content of foods: Practically all foods contain some fluoride. Thus, in studying fluoride intake, it is important to consider the amount ingested from food as well as from drinking water. In fact, as Dr. Knutson has pointed out, no one has so far been able to produce a diet for humans or for animals-which is fluoride-free. Chart 1 shows that a number of foods contain more than 0.2 part per million of fluoride. Honey, cocoa, spinach, and apples have approximately 1 part per million. Teas contain 30 to 60 parts per million. Continuing with chart 2, we find that some meats and seafoods have a fluoride content up to 27 parts per million. A pound of canned mackerel, for instance, may provide as much fluoride as 15 quarts of drinking water containing 1 part per million of fluoride, or 12 to 15 milligrams. The daily fluoride intake from food and water has been estimated at from 0.5 to 2 milligrams, varying with the age of the individual. This can be seen in chart 3. The effect of fluoride on bone fractures and bone development: The possibility that the use of water containing fluoride might predispose the individual to bone fracture has received careful study by our staff at the National Institute of Dental Research. 1,450 high school boys, 15 to 17 years of age, and 1,600 young men, 18 to 25 years of age, were questioned individually concerning their fracture experience. Each of these individuals had consumed domestic water containing up to 5 parts per million of fluoride. The data for the high school boys are in chart 4, and that for the young adults are in chart 5. They show no unusual fracture experience. Another study of this kind involved the review of the physical examination records for 1,000 men at the Lubbock, Tex., Induction Center. This group included persons who had been exposed to drinking water containing more than 5 parts per million of fluoride. This survey showed no differences in fracture experience which could be related to the fluoride concentration in the water. For example, the incidence of fractures among persons from Lubbock, where the water contained 5 parts per million of fluoride, was not higher than the incidence of fractures among individuals from Washington, D. C., where the water was virtually fluoride-free. A study has also been made of the relation of fluoride in drinking water to the development and calcification in the bones of the hand. X-rays were used to compare the hands of two large groups of children. The first of these groups consisted of nearly 1,300 children, 7 to 14 years of age, who had a history of continuous residence in Amarillo and Lubbock, Tex., and who had consumed domestic water containing 3 to 6 parts per million of fluoride. The second group consisted of about 800 children of the same age from Cumberland, Md., where the water was virtually fluoride-free. The results are presented in chart 6. No differences were observed when the calcification and skeletal development rates were compared with recognized standards. This clearly demonstrated that bone development and calcification rates are the same among children in high and low fluoride areas. The urinary excretion of fluoride: The facility with which the kidneys eliminate fluoride may be seen in the data collected from the Grand Rapids, Mich., study initiated in 1945, from the study in Montgomery County, Md., started in 1951, and from the data collected in Aurora, Ill. Montgomery County adults, as shown in chart 7, eliminate 1 part per million of fluoride in the urine, which corresponds to the 1 part per million fluoride content of the drinking water. Fluoride excretion for children of this county up to 14 years of age is at a somewhat lower level, but will equal 1 part per million fluoride in about 4 years, as can be seen from the Grand Rapids data in chart 8. In the third study, children of comparable age from Aurora, Ill., drink water containing 1 parts per million of naturally occurring fluoride, and they excrete the same concentration in the urine. While all three of these communities have a similar fluoride concentration in their water supplies, it is important to note the differences in source of the element. Grand Rapids adds sodium fluoride; Montgomery County adds sodium fluosilicate; and Aurora uses water which contains fluoride naturally. In all three communities, the excretion of fluoride in the urine is similar, regardless of the source of the fluorine. It may therefore be concluded that whether the fluoride occurs naturally or is added, the body excretes fluoride in the same manner. The effect of low-level fluoride ingestion in animals: A large body of knowledge has been accumulated on factors influencing the deposition of fluoride in the bones of the animal organism. I should like to present the major findings of some of these studies which shed light on the manner in which the body handles a low level of fluoride in the drinking water. These experiments, using the white rat as the experimental animal, were designed to answer three questions. 1. How is fluoride deposited in the bones and teeth when exposure has occurred over a long period of time? Rats receiving 10 parts per million of fluoride deposited this element in the bones up to an age beyond which no further accumulation of fluoride occurred. As indicated in chart 9, the oldest rats were 420 days old, which is equivalent to roughly 35 years of age in the human. This experiment approximates a situation in which human beings have been reared on a fluoridated drinking water. From these findings, it would be expected that persons receiving a low level of fluoride in their water would deposit this element up to a certain age beyond which no further deposition would take place. 2. How is fluoride deposited in the bones and teeth when the initial exposure to waterborne fluoride occurs at varying age? In this study rats of different ages, with no previous exposure to fluoride, received similar quantities of fluoride in their drinking water. As can be seen in chart 10, the amount of fluoride deposited in bone varied substantially according to the age of the rat. Older rats deposited appreciably less than the younger ones. The range of age in the rats-from 30 to 330 days-is comparable to a range of 3 to 30 years in the human. From this finding, it would be expected that when a community water supply is fluoridated, older individuals would deposit less fluoride in their bones than do children. It should be remembered that the deposition of fluoride in the bones of children is completely compatible with good health, as evidenced by X-ray examinations of the hands, forearms, and legs of children in Newburgh, N. Y., six years after the start of water fluoridation. These X-rays showed no differences which could be attributed to ingested fluoride, and, in addition, blood counts and urinalyses revealed no evidence of any untoward effects. 3. Does fluoride affect the rate of growth of newly forming bone? This seemed to us to be another important question to be answered concerning the effects of fluoride. Elongation of a long bone, such as the tibia or shin bone, occurs at both ends. One of our studies in rats involved measurement of the rate of growth of both ends of the tibia. The data are charted in chart 11. Some of the rats received distilled water, and some received 10 parts per million of fluoride. There was no difference in the rate of growth at either the upper or the lower end of the tibia as a result of fluoride ingestion. I should like now to summarize the five major points brought out in my statement. 1. Many foods contain appreciable amounts of fluoride. This is particularly true of teas, meats, and fish. 2. Even with fluoride in water at level 4 to 5 times greater than that advocated for caries prevention, there was no effect on bone development or fracture experience. 3. Both children and adults excrete 1 part per million of fluoride in the urine when the drinking water contains an equal concentration |