Excerpts from report:
Page 5 & 17: Although exposure to fluoride reduces dental caries at a given age, and delays the onset of the cavitation process, it does not completely prevent dental caries, and dental caries still progresses in populations exposed to fluoride (pages 23-35).
Pages 14-15: The overall quality of the evidence pertaining to dental caries was generated from the eight cohort studies analysed (Annex 1). None of the studies were excluded on the basis of quality. Seven of the eight studies reported higher dental caries with higher sugars intake. Six of the eight studies accounted for fluoride exposure. For the analysis relating to dental caries in adults, data were not downgraded for indirectness, although all cohort studies were conducted in children. The etiology of dental caries is the same in children and adults and, because dental caries tracks from childhood to adulthood, the negative health effects of dental caries are cumulative. Five of the eight cohort studies enabled the comparison of dental caries development when free sugars intake was equivalent to an amount less than 10% of total energy intake or more than 10% of total energy intake. All of these studies reported higher levels of dental caries when the amount of free sugars intake was more than 10% of total energy intake compared with it being less than 10% of total energy intake.
The data extracted from the cohort studies was not suitable for pooling and subsequent meta-analysis because of the high degree of variability in how the data were reported. This variability included differences in selection and reporting of outcomes, study populations, types of interventions, how sugars intake and caries were measured and analyses were performed, the types of sugars reported on, and the availability of information on level of fluoride exposure. Overall effect and quality of evidence for free sugars intake and dental caries was determined based on qualitative analysis of all relevant cohort studies.
Three national population studies were identified that enabled comparison of dental caries levels when annual per capita free sugars intake was less than 10 kg/person/year (about 5% of total energy intake), compared with more than 10 kg/person/year but below 18.25 kg/person/year (about 10% of total energy intake). In all three studies, lower levels of dental caries development were observed when per capita free sugars intake was less than 10 kg/person/year. Across all studies, a log-linear dose–response relationship was also observed at free sugars intakes well below 10 kg/person/year (i.e. <5% of total energy intake).
All three population studies were conducted in Japan on children with low fluoride exposure. However, dental caries persists in fluoridated populations, especially in adults (41, 42); therefore, all populations, irrespective of fluoride exposure, could potentially benefit from a low level of free sugars intake to protect against dental caries.
Page 20: Research gaps and future initiatives
… Need to undertake new cohort studies with improved methodology for assessing dietary intake in areas that have or have not been fluoridated. It will be difficult to undertake clinical trials, but undertaking studies with improved dietary assessment would make it possible to more rigorously review threshold issues.
This footnote was in the following Annex and Tables:
There was no evidence of risk of bias. Six of the eight studies accounted for fluoride exposure, and a consistent association between free sugars intake and caries was detected.
Annex 1: GRADE evidence profiles – footnote e
Table 2: GRADE evidence profile for the effect of an increase in free sugars intake in adults – footnote h
Table 3: GRADE evidence profile for the effect of a reduction in free sugars intake in children – footnote f
Table 4: GRADE evidence profile for the effect of an increase in free sugars intake in children – footnote e
Table 5: GRADE evidence profile for the effect of decreasing intake of free sugars to below 10% of total energy intake – footnote b
Table 6. GRADE evidence profile for the effect of decreasing intake of free sugars to below 5% of total energy intake –
footnote e – All three studies assessed permanent dentition of children only; however, data were not downgraded for indirectness as the etiology of dental caries is the same in children and adults (although enamel of the primary dentition is softer and more vulnerable to demineralization by plaque acid), and the negative health effects of dental caries are cumulative with age. These studies were undertaken in populations with low fluoride exposure; however, there is no expectation of a difference in effect when extrapolating to populations with good fluoride exposure as the relationship between sugars intake and dental caries persists in the presence of exposure to fluoride.
- Sheiham A, James WP. A new understanding of the relationship between sugars, dental caries and fluoride use: implications for limits on sugars consumption. Public Health Nutr. 2014:1–9.
- Slade GD, Sanders AE, Do L, Roberts-Thomson K, Spencer AJ. Effects of fluoridated drinking water on dental caries in Australian adults. J. Dent. Res. 2013; 92(4):376–382.
- Lawrence HP, Sheiham A. Caries progression in 12- to 16-year-old schoolchildren in fluoridated and fluoride-deficient areas in Brazil. Community Dent. Oral Epidemiol. 1997; 25(6):402–411.
- Griffin SO, Griffin PM, Swann JL, Zlobin N. New coronal caries in older adults: Implications for prevention. J. Dent. Res. 2005; 84(8):715–720.
- Broadbent JM, Thomson WM, Poulton R. Progression of dental caries and tooth loss between the third and fourth decades of life: A birth cohort study. Caries Res. 2006; 40(6):459–465.
• See article from UK, Recommended Daily Intake of Sugar “should be halved”