Evidence that 100% fruit juice consumption is associated with a BMI gain in children

In a recent study published in JAMA Pediatrics, researchers assess the effect of 100% fruit juice on weight gain in children and adults.

Study: Consumption of 100% fruit juice and body weight in children and adults. Image Credit: New Africa / Shutterstock.com

Background

Consuming 100% fruit juice offers a convenient way to meet daily fruit recommendations, thereby providing essential nutrients like vitamins, antioxidants, and polyphenols. However, concerns arise about potential weight gain due to the high levels of free sugars and energy in these beverages. Furthermore, limited fiber in juice as compared to whole fruits may lead to lower satiety and increased energy intake.

Existing evidence on 100% fruit juice and weight gain presents mixed findings and is influenced by various factors such as considering total energy as a mediator, juice types, and variable adjustment for confounders. Inconsistencies in international guidelines further highlight the need for evidence-based recommendations, particularly as a significant proportion of children and adolescents regularly consume fruit juice.

The aim of the present systematic review and meta-analysis was to evaluate the evidence on 100% fruit juice consumption and weight gain in pediatric and adult populations to inform public policy and clinical guidelines.

About the study

The MEDLINE, Embase, and Cochrane databases were searched from their inception until May 18, 2023. Prospective cohort studies of at least six months, as well as randomized clinical trials (RCTs) with interventions of two weeks or longer, were included in the analysis.

A total of 17 prospective cohort studies included children with a median age of eight years, whereas six prospective cohort studies included adults with a median age of 48 years.

Although no RCTs involving children were identified in the analysis, 19 RCTs involving adults with a median age of 42 were identified. The included RCTs compared 100% pomegranate, berries, tart cherry, apple, citrus, or grape juice with standard diet alone or noncaloric controls such as water or non-nutritive sweetened beverages.

The risk of bias was evaluated using the Newcastle-Ottawa Scale and Cochrane Risk of Bias for prospective cohort studies and RCTs, respectively. Outcome measures for prospective cohort studies were standardized by data transformation.

The primary outcome was the change in body mass index (BMI) and body weight for every eight ounce serving increment of 100% fruit juice for children and adults, respectively. Studies reporting changes in juice intake as compared to weight were separately analyzed.

The main analysis used estimates unadjusted for energy intake, and a secondary meta-analysis considered estimates that were adjusted for total energy intake. Additionally, an analysis extrapolating BMI or body weight change to a year-long period was conducted.

Study findings

The risk of bias analysis indicated high quality of the included studies. However, a publication bias was evident in cohort studies in children.

A positive association was observed between 100% fruit juice consumption and weight gain in children. Prospective studies not adjusting for energy intake showed a significant positive association between 100% fruit juice consumption and body weight gain in adults, whereas studies adjusting for energy intake found a significant inverse association, thus suggesting that energy intake may mediate this relationship.

Comparatively, in RCTs involving adults, no significant association was observed between the consumption of 100% fruit juice and body weight change.

GRADE assessments showed that the certainty of evidence for the association was very low for cohort studies in children and adults and low for RCTs in adults. NutriGRADE assessments suggested moderate quality for cohort studies in children and RCTs in adults, as well as low quality for cohort studies in adults.

The study is strengthened by its inclusion of cohort and RCT study designs, as it allowed for the adjustment of confounding factors and improved the generalizability of the results to real-world settings. Notable limitations of the study include potential residual confounding in observational designs, inaccuracies in self-reported dietary assessments, substantial heterogeneity in outcomes, and a lack of RCTs in children, thus emphasizing the need for future research in this area.

Conclusions

The analysis identified a positive association between 100% fruit juice consumption, slight BMI gain in children, and slight weight gain in adults, which was potentially mediated by calories. These findings support limiting the consumption of 100% fruit juice to prevent obesity and improve public health outcomes.