Controlled water fluoridation study projects were then begun in 1945 in Grand Rapids, Mich.; Newburgh, N. Y.; Brantford, Ontario, and later in several other cities. These projects were designed to determine whether a purposefully fluoridated drinking water would produce the same beneficial effect as a naturally fluoridated one. A corollary purpose was to gather experience on the mechanical problems of adding and controlling the fluoride concentration in a water system. The results from these fluoridation study projects have amply demonstrated that the supplementation of a fluoride-deficient water supply is a practical, safe, effective, and an economical procedure. In view of these facts, in April 1951, the Surgeon General indicated that the Public Health Service endorsed the fluoridation of public water supplies. Let me consider now the specific dental benefits associated with the ingestion of a proper concentration of fluoride. From chart 1, shown to my right, here, you can see the actual change effected by fluoridation. CHART 1 Decayed, Missing & Filled Teeth Per Child (FLUORIDE & NON-FLUORIDE COMMUNITIES) The top line represents the amount of tooth decay experienced by hildren living in Grand Rapids, Mich., before that city added fluoride o its water supply, that is, before 1945. It shows a progressive ncrease in dental caries at the rate of about a tooth each year. This ate of increase continues incidentally, until adulthood is reached. The bottom line indicates the level of tooth decay in children from Aurora, Ill., whose drinking water contained 1.2 parts per million of naturally occurring fluoride. As you can see, decay occurs in these children at a considerably lower level. The contrast shown in this 48391-54-24 chart has been confirmed by observations on thousands of children in communities throughout the United States. The impact of fluoridation on Grand Rapids children is shown in chart 2. 16 CHART 2 Decayed, Missing & Filled Teeth* Per Child 5 6 7 8 6 10 11 12 14 15 16 -12 8 *PERMANENT TEETH The center line represents the amount of tooth decay observed in Grand Rapids children in 1953, 9 years after fluoridation started. It has been superimposed upon the first chart. You can see how very closely the level of tooth decay in Grand Rapids now approximates that in Aurora, especially in the younger age groups. Children 11 years of age or younger showed the greatest benefit. However, is interesting to note that children who were 3 to 7 years of age at the start of fluoridation and who are now 12 to 16, also acquired a considerable amount of protection. Another of our studies produced evidence that the dental protec tion of fluoridation continues throughout life. In chart 3 you can see the difference in the level of tooth decay in adults residing in Colorado Springs, Colo., who were served by a water supply containing 2.5 parts per million of fluoride, compared with the tooth decay observed in adult residents of Boulder, Colo., which has a fluoride-free water supply. It is apparent that those persons living in Colorado Springs continue to have about one-third the tooth decay found in adult residents of Boulder. it 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 |