Scientists raise questions about European expert body’s classification of “fruit juice”

In its 2022 opinion of the safety of dietary sugars, the European Food Safety Authority (EFSA) reported associations between consuming ‘fruit juice’ and risk of type 2 diabetes and higher body weight. At the time, it was unclear which definition was being used since an earlier draft referred to ‘100% fruit juice’ before being changed to the less precise ‘fruit juice’. It’s worth noting that even the more general term ‘fruit juice’ is still defined under European law as a product that does not contain added sugars.

Now a study by Chen and colleagues [1] has raised questions about the definition of fruit juice in the EFSA report, arguing that EFSA appears to have misclassified fruit juice and used an invalid approach to synthesise the evidence.

As the researchers explain, prospective cohort studies have found protective or neutral associations between 100% fruit juice and cardiometabolic diseases including cardiovascular disease, stroke, metabolic syndrome, and hypertension. This may reflect the fact that, excepting fibre, 100% fruit juice has a similar nutritional profile to whole fruits. Indeed, this was one of the justifications for the recently updated Nordic Nutrition Recommendation including a moderate serving of fruit juice.

To provide clarity on definitions, Chen and colleagues re-analysed the prospective cohort study data used in EFSA’s opinion. Firstly, they examined the wording of the studies’ food frequency questionnaires which asked participants about “fruit juice” rather than “100% fruit juice.” This means that fruit drinks containing added sugar may have been included in the data.

Secondly, Chen and colleagues examined the approach used by EFSA to synthesise the evidence on the link between 100% fruit juice intake and body fat outcomes. Rather than quantifying the relationship, EFSA counted how many studies were significant versus how many were not significant. This is not considered to be a valid approach in meta-analyses.

To address these two issues, Chen and colleagues categorised the prospective cohort studies into two groups: 1) 100% fruit juice studies which included pure fruit juice and 100% fruit juice, and 2) non-defined fruit juice studies which did not specify the type of fruit juice. They then performed new meta-analyses on the data.

Using this updated approach, they found:

●      No statistically significant association between total fruit juice and type 2 diabetes incidence.

●      No significant association between 100% fruit juice and type 2 diabetes incidence.

●      A significant association between non-specified fruit juice and increased type 2 diabetes incidence.

Additionally, type 2 diabetes incidence increased in line with increased intake of non-specified fruit juice, but this was not the case for 100% fruit juice.

Regarding EFSA’s suggested link between fruit juice and increased body fat, Chen and colleagues found no link between 100% fruit juice and incident abdominal obesity. While their analyses showed an association between 100% fruit juice and increased body mass index, this was reported to be “clinically trivial.”

In conclusion, the study by Chen and colleagues highlights the importance of separating 100% fruit juice, as defined in law, from sugar-sweetened versions of fruit juice drinks. These are clearly not the same thing when looking at health markers and this should be acknowledged by expert bodies and policy makers.

Reference

1. Chen V et al. (2023). https://pubmed.ncbi.nlm.nih.gov/36737479/