Fluoride balances during early and late pregnancy.

Information useful in estimating the occupational fluoride hazard to pregnant women is scanty. Fluoride excretion and balances were determined in 18 young women--seven who were not pregnant, six in early pregnancy (second quarter), and five in late pregnancy (fourth quarter)--over a 20-day period under confined metabolic conditions. The total fluoride intake averaged 1.35 mg/day (0.35 mg from the diet, 1 mg from a mineral capsule). Urinary fluoride excretion levels for the three groups were similar and averaged 0.95, 1.03, and 1.15 mg/day, respectively. On the average, 88% of the total fluoride excreted was in the urine and the remainder in the feces. With few exceptions, the women in each group demonstrated small positive balances; the averages were +0.19, +0.16, and +0.14 mg/day, respectively. The differences were small and not statistically significant (p greater than 0.1). These data indicate that fluoride metabolism is not markedly altered during the course of pregnancy.

Effect of dichloromethylene diphosphonate on fluoride balance in healthy men.

Healthy men with a daily intake of 0.37 mg fluoride were given dichloromethylene diphosphonate (Cl2MDP) or a placebo during a period of ambulation followed by bed rest. In both groups, serum ionic fluoride was unchanged, and fluoride balances were negative, but Cl2MDP significantly reduced loss of fluoride in the treated groups.

Fluoride balance studies in healthy men during bed rest with and without a fluoride supplement..

In a program of studies of disuse osteoporosis, fluoride balances were determined in healthy men during ambulation and then during bed rest for 6 to 17 wk. Control subjects ingested basal diets containing 0.4 mg fluoride per day, whereas experimental subjects received 10-mg fluoride supplements in divided doses with meals. Fluoride and calcium were measured in diets, urine, and feces. Serum analyses included calcium and ionic fluoride. Fluoride balances during both phases were uniformly negative in control subjects (mean -0.46 mg/day) but uniformly positive in supplement subjects (mean +2.58 mg/day). Calcium balances were markedly negative during bed rest in both groups. Serum fluoride concentrations increased proportionally to fluoride intake, averaging 0.016 ppm in the controls and 0.045 ppm in the supplement subjects. The supplement of 10 mg fluoride daily did not protect against bed rest-induced calcium loss, or cause any clinical or laboratory abnormality in any subject.

Fluoride balance studies in ambulatory healthy men with and without fluoride supplements.

Fluoride balances were determined in healthy adult males under metabolic ward conditions. This is the first fluoride study to use the diffusion method in exploring the balances of subjects ingesting basal (i.e., everyday) diets with deionized water for cooking and drinking. Certain groups were given daily supplements of 5 or 10 mg. fluoride as sodium fluoride in divided doses with meals. Fluoride was measured in the diets, sodium fluoride tablets, urine, feces, and serum. Approximately 90% of the fluoride excreted was found in the urine and the remainder in the feces in all groups. In the control subjects, fluoride balances were uniformly negative (mean of -0.40 mg/day); in contrast, balances were uniformly positive (mean of +1.38 and +2.88 mg/day, respectively) in subjects receiving 5 or 10 mg F supplements daily. Serum ionic fluoride concentration increased proportionally to fluoride intake and averaged 0.016, 0.029, and 0.040 ppm in the control, 5-mg and 10-mg groups, respectively. These fluoride supplements did not cause any clinical or laboratory abnormality in any subjects.

Fluoride balances in pregnant and nonpregnant women.

In planning health protection for pregnant as well as nonpregnant women exposed to fluorides, information about their fluoride metabolism is essential. The authors determined fluoride balances in small groups of young women maintained on two different low-fluoride diets for one or two 21-day periods in a metabolic unit. One diet contained an average of 0.41 mg F/day, and the other contained an average of 0.27 mg F/day. Excretion of fluoride in pooled three-day collections for each subject was about 80% in the urine and 20% in the feces. Pregnant (last half of term) and nonpregnant women demonstrated small negative fluoride balances; the averages were about -0.32 mg F/day and -0.15 mg F/day, respectively. Similar values have been found for young males in other studies. Pregnancy in these subjects did not markedly alter normal fluoride metabolism.