Researchers from the Dublin Dental University Hospital at Trinity College have found that 3 year olds in Ireland are consuming on average 10 level teaspoons of ‘free sugar‘ a day.
Free sugars includes those sugars added during the production or processing of food and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates.
Dietary free sugars are the most important risk factor for dental caries and can contribute to excess energy intake with little nutrient benefit.
This study, published in the European Journal of Nutrition used a modified algorithm to estimate the free sugar intake in Irish 3 year old pre-schoolers using data from the National Preschool Nutrition Survey (NPNS) and the Growing Up in Ireland survey (GUI).
The results indicate that 75 percent of three-year-olds had free sugar intake greater than the maximum recommended by WHO guidelines for free sugar intake, while only 4 percent met the lower threshold.
The ideal recommendation by WHO is to further reduce the amount of free sugar to a maximum of four to five teaspoons, if possible, and aim towards a maximum frequency of once per day of sugary foods and drinks.
Fruit juices and smoothies, dairy products (including yoghurts and fromage frais), soft drinks (including squashes, cordials and fruit juice drinks), confectionary (chocolate and non-chocolate), and cakes and biscuits were the key food sources for free sugar, contributing to more than three-quarters of total free sugar intake.
Lead author of the study, Michael Crowe from the Dublin Dental University Hospital said:
“A large majority of three-year-old Irish children do not meet the WHO recommended guidelines for free sugar intake and almost none meet the desired conditional recommendation.
Free sugar intake is excessively high, even at this early age, and reducing the consumption, especially snacking, of low nutrient, discretionary food and drink should be a helpful approach to achieving an overall reduction in free sugar consumption.”
Dentists advise patients to reduce sugar intake by cutting sugary snacks and limit consumption to main meals to prevent dental caries.
Currently, it would appear that children’s snack choices are dominated by foods high in free sugars so substituting these snacks with healthier alternatives would seem one obvious dietary strategy to help reduce free sugar intake.
The study shows that ‘chocolate’ and ‘non-chocolate confectionary’ and ‘cakes and biscuits’ are commonly consumed as snacks, which means that they could be cut or replaced with healthier alternatives in order to reduce the frequency and amount of sugar throughout the day.
The results have relevance for both the general and oral health of pre-schoolers as a high sugar intake affects both aspects of health.
As well as concerns about establishing unhealthy eating patterns at an early age that may influence obesity risk, sugar intake is a key risk factor in the progression and reversal of early dental caries.
The prevalence of oral health problems in young children has increased in recent years, following a decline in previous decades.
Early childhood caries is the most prevalent dental problem in pre-schoolers, one of the most common causes of hospital admission and the most frequent reason for unplanned general anaesthesia in children.
As highlighted by the team’s analysis and that of previous researchers “RTEBC’ (ready to eat breakfast cereals) and ‘fruit juices’ are items of consumption that have become difficult to classify as ‘healthy’ or ‘unhealthy’ as they can be an important source of nutrients for young children but also contain relatively high levels of free sugar.
Currently, food manufacturers in the EU are not required to include free sugar content in their labelling which makes it difficult for consumers to quantify their consumption.
Furthermore, it is difficult for consumers to understand the different types and sources of dietary sugars and questionable as to whether they could use this information to attempt to meet the WHO guidelines.
The findings should help dentists and dental hygienists to understand the specific food and drink patterns to focus on when carrying out dietary risk assessment and counselling for preschool children and to be aware that most children do not meet the WHO population guideline.
This analysis also highlights the lack of standardised methods for free sugar estimation and the importance of using appropriate methods for quantifying sugar intake at the food level.
Two systematic reviews were commissioned1, 2 to assess the effects of increasing or decreasing intake of free sugars on excess weight gain and dental caries – two health outcomes identified as critical in relation to free sugars intake. Initially, several other outcomes, such as diabetes and cardiovascular disease (CVD), were also considered by the NUGAG Subgroup on Diet and Health. However, after extensive discussions, it was decided that excess weight gain and dental caries should be the key outcomes of concern in relation to free sugars intake. Risk of developing type 2 diabetes and CVD is often mediated through the effects of overweight and obesity, among other risk factors. Therefore, measures aimed at reducing overweight and obesity are likely to also reduce the risk of developing type 2 diabetes and CVD, and the complications associated with those diseases.
The specific research questions guiding the systematic reviews undertaken were:
- What is the effect of a decrease or increase in free sugars intake in adults and children?
- What is the effect of restricting intake of free sugars to below 10% of total energy?3
Body weight
The systematic review on body weight (39) examined the effects of free sugars intake on excess adiposity; that is, whether reducing or increasing the intake of free sugars influences measures of body weight in adults and children, and whether current evidence provides support for the existing recommendation to reduce intake of free sugars to less than 10% of total energy intake. Body weight was selected as an outcome, in view of the extent to which comorbidities of obesity contribute to the global burden of NCDs. Studies that included interventions involving advice to decrease or increase intake of free sugars, or sugar-containing foods or beverages, without emphasizing the need to achieve weight loss, were included in the review. In addition, evidence for differences between higher and lower free sugars intake was assessed from randomized controlled trials (RCTs) in which free sugars intake was altered but total energy intake was strictly controlled (i.e. isoenergetic). Trials that were specifically designed to achieve weight loss were excluded. It was acknowledged that the studies identified by this approach would inevitably be heterogeneous, that it would be difficult to disentangle the effects of a number of different dietary changes that might occur as a consequence of altering intake of free sugars, and that it might be difficult to identify a continuous relationship (dose–response) between intake of free sugars and body weight.
The systematic review of the effect of intake of free sugars on body weight included 30 of the 7895 RCTs and 38 of the 9445 cohort studies initially identified as meeting the inclusion criteria. Meta-analysis of the five trials in adults with ad libitum diets (i.e. no strict control on food intake) found that reduced intake of free sugars was associated with a decrease in body weight (−0.80 kg; 95% confidence interval [CI]: −1.21, −0.39). Meta-analysis of the 10 trials that involved increasing sugars intake (mostly sugar-sweetened beverages) suggested a comparable weight increase (0.75 kg; 95% CI: 0.30, 1.19). Meta-analysis of the 11 trials that examined isoenergetic exchanges of free sugars with other carbohydrates showed no change in body weight (0.04 kg; 95% CI: −0.04, 0.13).
The review identified five trials in children in which the intervention involved recommendations to reduce sugar-sweetened foods and beverages, but these trials were characterized by generally low compliance with dietary advice, and showed no overall change in body weight as measured by standardized body mass index (BMI) or BMI z score (0.09; 95% CI: −0.14, 0.32). However, meta-analysis of five prospective cohort studies, with follow-up times of 1 year or more, found that those children with the highest intakes of sugar-sweetened beverages had a greater likelihood of being overweight or obese than those children with the lowest intakes (odds ratio [OR] 1.55; 95% CI: 1.32, 1.82). Significant heterogeneity was evident in one of the meta-analyses, and some trials were subject to potential bias that could have influenced the findings; nevertheless, sensitivity analyses showed that the trends were consistent and associations remained, even when excluding data from the potentially biased studies and studies contributing most to the observed heterogeneity.
The overall quality of the available evidence for changes in body weight in relation to both increasing and decreasing free sugars intake in adults was considered to be moderate; this was due to downgrading for possible biases identified in a minority of studies and potential publication bias because of the small number of trials identified (Annex 1). In children, the quality of evidence for an association between a reduction in free sugars intake and reduced body weight was similarly considered to be moderate, whereas the quality of the evidence for an association between an increase in free sugars intake and increased body weight was considered to be low (Annex 1).Go to:
Dental caries
The systematic review on dental caries addressed the relationship between the level of free sugars intake and dental caries in adults and children (40).
A literature search for studies conducted in adults identified two non-randomized intervention trials and two observational studies (cross-sectional studies) that met the inclusion criteria. In addition, one ecological study conducted in both adults and children was identified. No RCTs or longitudinal cohort studies were identified that met the inclusion criteria.
The studies included about 1200 participants in total, and all studies in adults were conducted in industrialized countries.
A literature search for studies conducted in children identified one non-randomized intervention study and 50 observational studies that met the inclusion criteria.
The observational studies included eight longitudinal cohort studies, 20 ecological studies (including one with both adults and children) and 22 cross-sectional studies.
No RCTs were identified that met the inclusion criteria.
Without including estimates on sample or population size from the population or ecological studies, the studies included more than 260 000 participants.
Among the 47 studies that reported at least one positive association between sugars intake and dental caries, 42 were conducted in children, four in adults and one in a mixed population of both adults and children.
Six studies reported both positive and null findings, depending on the age or ethnic group of the participants; seven studies reported null findings in all measured associations; and two studies reported at least one negative association. Positive associations between free sugars intake and dental caries were detected in all ages (including <5 years to >65 years); in developing, transitional and industrialized countries; and in all decades of publication of results. Overall, the evidence suggests a positive association between amount of free sugars intake and dental caries in both children and adults.
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.
For the systematic review on dental caries, in most studies identified, dental caries was diagnosed at the level of cavitation (i.e. advanced stage).4 However, the pathological process of dental caries begins with pre-cavitation damage (43, 44), which may occur at amounts of sugars intake below that associated with limited or no cavities.
The negative health effects of dental caries are cumulative because the disease is the result of lifelong exposure to the dietary risk factor (i.e. free sugars).
Being free of cavities in childhood does not mean being caries-free for life, and most dental caries is now occurring in adults (41, 45–47).
Therefore, even a small reduction in risk of dental caries in childhood is of significance in later life.
More information: Michael Crowe et al. Estimation and consumption pattern of free sugar intake in 3-year-old Irish preschool children, European Journal of Nutrition (2019). DOI: 10.1007/s00394-019-02056-8
Journal information: European Journal of Nutrition
Provided by Trinity College Dublin
