Journal of Food Science 1966; 31: 941-946.
The Fluoride Content of Some Foods and Beverages - a Brief Survey Using a Modified Zr-SPADNS Method.
Marier J, Rose D.
Food Chemistry Section, Division of Biosciences, National Research Council, Ottawa, Canada.
SUMMARY: An analytical method is described that estimates up to 2.0 ppm of fluoride in a 10-g sample of food, with a standard deviation of 0.093 PPM F per test. A brief survey of beverages and canned vegetables indicates that the use of fluoridated water (i.e., 1.0 PPM F) by food or beverage processors will increase the fluoride content of the products by 0.34 - 0.75 PPM (av. increase: 0.50 PPM). On the basis of food analyses and a concomitant study of the fluid intake of laboratory personnel, it is estimated that the total ingestion of fluoride per day by healthy "indoor" workers will range from 2 to 5 mg per day. Implications of these findings are discussed.
As more cities accept the practice of adjusting the fluoride content of municipal water supplies to a concentration of 1.0 part-per-million (i.e., 1 PPM), more food and beverage processing plants will utilize water containing this level of fluoride, and more fluoride will be present in commercially prepared foods and beverages. Although studies of the dental benefits derived from fluoride have been based on the level of fluoride in the drinking water, an important factor to be considered relative to general health and potential fluoride-induced injuries is the total fluoride intake from all sources (Cholak, 1960; Krepkogorsky, 1963; Waldbott, 1963).
McClure (1949) reviewed the fluoride content of foods prior to extensive fluoridation of municipal water supplies, but, in the opinion of the present authors (Rose and Marier, 1964), too little attention has been paid to the probable increases that have occurred as an indirect result of water fluoridation. Several surveys (Danielsen and Gaarder, 1955; Elliott and Smith, 1960; Ham and Smith, 1950, 1954; Krepkogorsky, 1963; Pisareva, 1955), have reported the amounts of fluoride ingested with foods, but none has included foods processed with water containing 1 PPM of fluoride. Martin (1951) has shown that simulated home-cooking of vegetables increased their fluoride content, but he did not study commercial processing procedures. Some authors (Bratton, 1953; Weir, 1953) have discussed the effect of fluoridated water on specific processes (wet-milling of corn; yeast cultures), while others (Cholak, 1960; Waldbott, 1963) have reviewed the subject of foodborne fluoride in general terms without presenting experimental data on the specific increases caused by the use of fluoridated water.
This paper presents a method for the estimation of fluoride in a 10-g sample of food, and also presents the results of analyses of some Canadian foods and beverages processed in areas using fluoride-adjusted (1.0 PPM) and low-fluoride waters. Also, the fluid intake of several individuals has been recorded and estimates of total fluoride ingestion by these individuals are presented.
Previous surveys have shown that the fluoride content of most foods is in the range of 0.2-0.3 PPM (Danielsen and Gaarder, 1955; Martin, 1951; McClure, 1949; Pisareva, 1955) and, on this basis, it has been estimated that the daily intake of foodborne fluoride would be 0.2-0.3 mg (Danielsen and Gaarder, 1955; McClure, 1949). Some analyses of entire meals have agreed with this estimate, reporting a value of 0.3 mg as the daily intake of fluoride with food (Armstrong and Knowlton, 1942; Ham and Smith, 1950). However, other investigations (Cholak, 1960; Ham and Smith, 1954) have reported a foodborne fluoride intake of 0.34-0.80 mg per day in areas where the water was essentially fluoride-free. More recently, Hodge and Smith (1965) have estimated that "for individuals whose drinking-water contains low levels or essentially no fluoride and for whom there are no special fluoride exposures, a 'normal' daily dietary intake in the United States probably lies in the range of 0.5 - 1.5 mg."
The present survey indicates that food processed with fluoridated water (1.0 PPM) will contain 0.6-1.0 PPM of F, instead of the"'normal" 0.2 - 0.3 PPM Therefore, the widespread use of fluoridated water (1.0 PPM) in food processing and preparation will probably mean a foodborne fluoride intake of ca 1.0 - 2.0 mg per day, i.e., and increase of about 0.5 mg per day over the 0.5 - 1.5-mg range estimated by Hodge and Smith (1965) for "fluoride-free" areas.
The observed fluid intakes of seven individuals ranged from 1 to 3 L per day, even though all of them were healthy males engaged in similar occupations in a similar environment. The variation reported is probably less than would have been observed between individuals with differing occupations and environments, and total fluid intake would undoubtedly be higher during warm-weather periods of the year.
The estimated total intake per day for fluoridated (1.0) communities varied from 2 to 5 mg per day, averaging 3.1 mg per day. Krepkogorsky (1963) has compiled data from districts where 1.0 PPM of fluoride is present in the drinking water; he reports an average daily total fluoride intake of 2.5 mg in England, 3.3 mg in the Ukraine, and up to 2.1 mg in other regions of the Soviet Union. However, traditional dietary habits can markedly affect the level of fluoride ingested with food; thus, Elliott and Smith (1960) have shown that the staple diet of Newfoundlanders could contribute 2.74 mg of fluoride per day in an area where the drinking water was fluoride-free. Krepkogorsky (1963) has recommended that the total fluoride intake by adults should not exceed 3.2 mg per day.
Although our survey was of limited scope, it nevertheless indicates that the use of fluoridated water in food processing will cause a significant increase in the fluoride content of foods and beverages. Our data suggest that some healthy individuals will ingest up to 5 mg of fluoride per day, under normal indoor vocational conditions for North America. Laborers exposed to outdoor summer conditions would, undoubtedly ingest still more, as would individuals subject to chronic polydipsia (Adams and Jowsey , 1965; Sauerbrunn et al, 1965). A need is clearly indicated for more extensive data. The total fluoride intake by individuals in a fluoridated community should therefore be monitored, and its medical significance carefully considered (Adams and Jowsey, 1965; Burgstahler, 1965; Krepkogorsky, 1963; Marier et al., 1963; Rose and Marier, 1964; Sauerbrunn et al., 1965; Waldbott, 1963).
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