Fluoride in human milk.

Reported contents of fluoride (F) in human milk vary considerably. The aim of this study was to determine the F content in human milk under different levels of F intake using a siliconfacilitated microdiffusion technique, which had a good accuracy and precision. The mean F concentration of colostrum from mothers in a 1.0 ppm and a 0.2 ppm F area was 0.36 +/- 0.02 mumol/l (+/- SEM) and 0.28 +/- 0.02 mumol/l, respectively. The mean F concentration of mature milk from a 1.0 ppm F area was 0.37 +/- 0.04 mumol/l. Within the 1.0 ppm F area, the intra- and interindividual differences in F concentration were very small. No statistically significant difference in milk F concentration between the two areas was found. Consequently, breastfed infants living in a 1 ppm or a 0.2 ppm F area will have an approximately equal F intake of 5-10 micrograms per day, in spite of great differences in F intake among the nursing mothers.