Response to: Problems With Relevance, Certainty, and Misinterpretation of Empirical Evidence

We thank Maganja et al for their letter regarding our umbrella review on the health effects of drinking 100% juice. Our review¹ applied standardized eligibility criteria across health outcomes to reduce bias in their selection. Included outcomes such as cardiovascular disease and mortality are well established for assessing the impact of a food on health. This is evidenced in the current review of the Australian Dietary Guidelines, where the National Health and Medical Research Council listed these as potentially relevant health outcomes.² The suggestion to focus primarily on body weight is a limited model to predict chronic disease risk,³ and we reported no effect on body weight outcomes. The greater diversity of included intermediate outcomes, such as inflammatory and metabolic markers, helps provide a more robust picture of chronic disease risk factors.^4,5 The decision to focus on 100% juice was consistent with a previous umbrella review,⁶ US dietary guidelines,⁷ and the NOVA classification system.⁸

Heterogeneity between studies was extracted and reported in Tables S3–S5 and Tables S9–S11. This was considered contextually alongside other domains in the overall study quality, reflected in our GRADE (Grading of Recommendations Assessment, Development, and Evaluation) assessments. Factors such as pulp, storage, and population nutritional status are not typically considered in population dietary guidance for fruit juice. Data that these factors mediated the health outcomes were limited.

The quality of evidence was mostly very low to low (GRADE), which is comparable to most other areas of nutrition science, including recent umbrella reviews on dietary sugars⁹ and ultra-processed foods.¹⁰ The moderate-quality evidence in our review included improvements in cardiovascular disease markers, such as a reduction in systolic blood pressure, and should not be overlooked. Globally, hypertension is the leading preventable risk factor for early death.¹¹

The limited health risks for 100% juice were a key finding. The statements “low to moderate levels…can provide exposure to beneficial nutrients and bioactive compounds, without the risks associated with excess consumption of free sugars and calories” and “100% juice can be incorporated into a healthy, balanced diet” reflected the balance of data. Others have made similar conclusions.^6,12 We support other health outcomes being considered in dietary guidance and practice for 100% juice, but this should be done in proportion to the quality of available data, and high-level evidence on satiety and dental health outcomes was lacking.

The quality of nutrition-related research is not accurately predicted by funding source.¹³ To minimize bias in our approach, best-practice guidelines for industry-funded research in nutrition were implemented¹⁴ and the raw data were published separately.¹⁵ We encourage data-driven judgments.

Finally, we assert that the findings hold significance for dietary guidance. The exclusion of 100% juice and categorization alongside sugar-sweetened beverages in some dietary guidelines was driven by the free-sugars content,^16,17 but health risks are not uniform across different sources of free sugars.¹⁸ Our study shows that such precautionary risks do not hold up in robust, comprehensive, systematic, and quantitative analysis of the health effects of 100% juice. More sophisticated models of its total nutritional composition may be required.

Author Contributions

All authors contributed to drafting and reviewing the manuscript.

Funding

None declared.

Conflicts of Interest

All authors independently work for, or collaborate with, FOODiQ Global, which gains funding for projects from government, not-for-profit, professional, community, and industry organizations. The funding body for this work, Hort Innovation, provided general feedback on the broad study topic; however, it had no contribution to the final methodology, implementation, or interpretation of results, or drafting of the manuscript.

REFERENCES