Associations of sugar and artificially-sweetened drinks with adiposity in a nationally representative cohort of adolescents

Childhood obesity is a growing problem in the UK.  Data estimate that over 1 in 5 reception children are overweight or obese, rising to over 1 in 3 children by the time they reach year 6 1  .  Furthermore it has long been recognised that obese children are likely to remain obese into adulthood 2 and obesity is associated with multiple serious chronic health conditions 3.  Obesity has a significant impact on not only the population’s health but also the NHS, with an estimated spend of £6.1 billion on obesity-related ill health in 2014-15 4.

 

Governing bodies including Public Health England have produced guidelines to encourage healthier eating which include reduction of sugar 5.  More recently the outgoing Chief Medical Officer for England suggested a ban on consumption of food and drink on public transport to tackle the obesity epidemic 6.  In response to the link between sugar consumption and weight gain, artificially sweetened beverages (ASBs) have been increasingly promoted as a solution to combating obesity.  However it seems that sales of sugary drinks are still high, making up over 2/3 of all drinks sales in the UK in 2018 7.  Thus it is important to know the evidence as to whether artificially sweetened i.e. lower sugar drinks can have an impact on obesity.

 

Our study builds on previous work by this research group exploring the link between obesity and both sugar sweetened beverages (SSBs) and ASBs 8.  We examine the associations between SSB and ASB consumption and changes in BMI and adiposity in a representative sample of UK children.

 

We used data from the UK Millennium Cohort Study (MCS), from 11,685 children followed up from ages 11 to age 14, with data collected in 2012 and 2014/15 respectively. Logistic regression was used to assess socio-demographic and behavioural correlates.  Linear regression was used to examine associations between SSB/ASB consumption changes in BMI and adiposity measures.

 

Nearly 3/4 of boys drank SSBs compared to 2/3 of girls at age 14 years.  For both boys and girls SSBs were more popular than ASBs with rates of consumption for ASBs at just over 1/2 for both sexes.

 

There appeared to be a correlation between fewer portions of fruit per day and higher SSB drinking rates compared to those who had more than 2 portions of fruit per day.  This relationship was not reflected with ASBs. Eating breakfast was associated with a lower rate of SSB consumption and also ASB consumption.  Watching more than 3 hours per weekday of television was associated with increased SSB consumption but there was no difference in ASB consumption for this group.  This association has been described elsewhere with recent media reports linking screen time with sugary drink consumption in teenagers 9.

 

For boys drinking ASBs, there was a clearer association between higher intake and greater increase in both % body fat and BMI.  This increase was greater for boys drinking ASBs daily than those who drank them weekly.  By contrast, boys who drank SSBs seemed to have a reduction in BMI and % body fat although this was not significant.

 

For girls who drank ASBs there was an association between higher consumption and greater increase in both BMI and % body fat.  For girls drinking SSBs the association between higher consumption and % body fat was clear, but less so for BMI.  Neither of these associations were significant, but there was a clear trend.

 

Our research group chose to look at the relationship between ASBs/SSBs and adiposity.  Adiposity is multifactorial and we considered and accounted for multiple confounders including ethnicity, maternal education, household income, fruit intake, breakfast consumption, physical activity, hours spent watching TV and method of travel to school.

 

Overall our results indicate high levels of ASB and SSB consumption among both sexes and a clear link to adiposity.  Furthermore, daily consumption seems to have a greater impact compared to weekly consumption.  However, we propose that this increased adiposity and BMI may be linked to puberty and the growth spurt, and that a certain degree of increased % body fat and BMI is normal in this age group.

 

With the recent data predicting that 250 million children worldwide will be obese by 2030 10, it is vital that we understand the impacts of both ASB and SSB consumption on adiposity.  These results are from before the soft drinks industry levy and it remains to be seen how much such policies will change consumer habits and these relationships.  Manufacturers are moving towards increasing their production of ASBs 11, but this may not impact on the childhood obesity problem as our data indicate associations with increased adiposity for consumption of ASBs as well as SSBs.

 

Being overweight carries significant health risks including diabetes, high blood pressure, heart disease, stroke and cancer to name just a few 12.  Therefore it is vital that our health policies to tackle obesity are based on robust evidence and perhaps swapping SSBs for ASBs might not provide the much needed solution.