Fluoride Consumption – Much Higher than We Are Told
During the systematic review of water fluoridation which spanned
1999-2000 (1), the dearth and poor quality of scientific evidence was a
major concern. In particular, no acceptable measurements were yet
available of fluoride consumption from all sources in any random sample of
the British population. The National Diet and Nutrition Survey published
in 2003 (2) the first such data, from 24-hour urinary fluoride assays from
most survey subjects.
Urinary values were dealt with in Volume Three of the report . The authors
inferred that 1% of men and 3% of women had intakes of fluoride above the
officially defined safe level of 0.05mg/kg/day. Whilst reviewing the raw
survey data for another research purpose I checked this statement. A
serious error came to light in the authors’ calculation.
The authors seem to have assumed that all fluoride consumed from any
source is excreted promptly in the urine. In fact, 90% of ingested
fluoride is assimilated into the blood stream (3), and half of that is
sequestered in calcified tissues. Only the remaining half, 45% of the
ingested fluoride, is excreted via the urine (4). On this basis daily
fluoride consumption is higher than daily excretion by a factor of 2.2.
When this correction is made, a much larger proportion of the sample is
shown to have consumed fluoride at or above the nationally defined safe
level. The correct figures range from 8.2% among 19-24 year old females to
25.5% for males aged 50-64.The mean for the entire sample (1429) is 20.2%.
This sample does not distinguish subjects receiving fluoridated water from
those who do not. Some 24-hour urines were incomplete, so these findings
under-estimate the truth.
The result suggests that a substantial proportion of the British
population are consuming fluoride in amounts that could be responsible for
undiagnosed symptoms. Persons accidentally consuming fluoride in excessive
amounts deserve to be identified and helped. It is time to raise medical
and dental awareness of this. Might not a square to detect fluoride
concentration be added alongside glucose to the urine testing dipstick?
The authors of the Survey Report and the relevant civil servant have been
advised of this apparent error, and have not refuted it. The Food
Standards Agency is considering its response.
References
1 McDonagh M, Whiting P, Bradley M et al. A systematic review of
water fluoridation. NHS Centre for Reviews and Dissemination: University
of York, 2000.
2 Henderson L, Irving K, Gregory J. The national diet and nutrition
survey: adults aged 19 to 64 years. HM Stationery Office, 2003;3:129-135.
3 World Health Organisation Monograph Series No 59. Fluorides and
Human Health. Geneva: World Health Organisation, 1970:75-89.
4 National Research Council (US). Health effects of ingested
fluoride. Washington: National Academy Press,1993:128-133.
Rapid Response:
Fluoride Consumption – Much Higher than We Are Told
During the systematic review of water fluoridation which spanned 1999-2000 (1), the dearth and poor quality of scientific evidence was a major concern. In particular, no acceptable measurements were yet available of fluoride consumption from all sources in any random sample of the British population. The National Diet and Nutrition Survey published in 2003 (2) the first such data, from 24-hour urinary fluoride assays from most survey subjects. Urinary values were dealt with in Volume Three of the report . The authors inferred that 1% of men and 3% of women had intakes of fluoride above the officially defined safe level of 0.05mg/kg/day. Whilst reviewing the raw survey data for another research purpose I checked this statement. A serious error came to light in the authors’ calculation. The authors seem to have assumed that all fluoride consumed from any source is excreted promptly in the urine. In fact, 90% of ingested fluoride is assimilated into the blood stream (3), and half of that is sequestered in calcified tissues. Only the remaining half, 45% of the ingested fluoride, is excreted via the urine (4). On this basis daily fluoride consumption is higher than daily excretion by a factor of 2.2. When this correction is made, a much larger proportion of the sample is shown to have consumed fluoride at or above the nationally defined safe level. The correct figures range from 8.2% among 19-24 year old females to 25.5% for males aged 50-64.The mean for the entire sample (1429) is 20.2%. This sample does not distinguish subjects receiving fluoridated water from those who do not. Some 24-hour urines were incomplete, so these findings under-estimate the truth. The result suggests that a substantial proportion of the British population are consuming fluoride in amounts that could be responsible for undiagnosed symptoms. Persons accidentally consuming fluoride in excessive amounts deserve to be identified and helped. It is time to raise medical and dental awareness of this. Might not a square to detect fluoride concentration be added alongside glucose to the urine testing dipstick? The authors of the Survey Report and the relevant civil servant have been advised of this apparent error, and have not refuted it. The Food Standards Agency is considering its response.
References
1 McDonagh M, Whiting P, Bradley M et al. A systematic review of water fluoridation. NHS Centre for Reviews and Dissemination: University of York, 2000.
2 Henderson L, Irving K, Gregory J. The national diet and nutrition survey: adults aged 19 to 64 years. HM Stationery Office, 2003;3:129-135.
3 World Health Organisation Monograph Series No 59. Fluorides and Human Health. Geneva: World Health Organisation, 1970:75-89.
4 National Research Council (US). Health effects of ingested fluoride. Washington: National Academy Press,1993:128-133.
Competing interests: None declared
Competing interests: No competing interests