Global study: children's lack of vegetable and fruit consumption linked to wealth and maternal factors

By Hugo Francisco de SouzaJul 3 2023Reviewed by Lily Ramsey, LLM

In a recent study in the PLOS Global Public Health Journal, researchers reviewed demographic and health surveys between 2006–2020 at the global scale to elucidate trends in zero vegetable or fruit consumption (ZVF) in infants.

They found that almost 46% of the world follows the practice of ZVF consumption, with socioeconomic conditions and mothers' employment status being significant predictors.

Study: Estimates and trends of zero vegetable or fruit consumption among children aged 6–23 months in 64 countries. Image Credit: Hananeko_Studio/Shutterstock.com

What is ZVF, and why does it matter?

After six months, human infants experience rapid growth and development, processes for which breastmilk alone is insufficient. Identifying that a diverse diet containing fruits and vegetables was essential, the United Nations Children's Fund (WHO-UNICEF) introduced zero vegetable or fruit consumption (ZVF) as a novel metric to evaluate infant and young child feeding (IYCF).

Introduced in 2021, the ZVF metric tests the proportion of children between the ages of 6-23 months who have not consumed any vegetables or fruits in the 24 hours preceding the query.

Prior research has shown that low vegetable and fruit consumption during this critical developmental period can drastically increase the risk of non-communicable diseases. Recognizing this, the WHO-UNICEF has placed ZVF among the top 10 risk determinants of mortality worldwide.

ZVF information monitors progress in optimal dietary practices in children nationally and globally. This data can then be used to spread awareness and inform government policy on matters relating to the health of young children. ZVF is one of many components of an umbrella metric called minimum dietary diversity (MDD), the latter of which has been shown to scale with household income.

While research on MDD in low-and-middle-income countries (LMIC) is widely available, ZVF data has historically been restricted to only high-and-middle-income countries, with LMICs being ignored.

Furthermore, until now, data on ZVF, even from economically privileged nations, has been temporally restricted (i.e., snapshots), with no literature available on (increasing/decreasing) ZVF trends over time.

About the study

In the present study, researchers collected and compiled data from 125 Demographic and Health Surveys (DHS) between 2006 and 2020. The surveys covered 64 nations and were structured to represent residence-, regional-, and country-level data.

DHS collected information via a standard questionnaire presented to a child's primary caregiver (parent or guardian) on the dietary spread of the child in the preceding 24 hours. Information about the age, education, income, media exposure, and employment status of key family members – especially the mother and child – were collected for downstream analyses.

The researchers simultaneously collected relevant climatic variables, including temperature, elevation, precipitation, and vegetation, to account for fruit and vegetable availability and price. Finally, temporal data, including whether the survey was conducted during the wet or dry months, were collected, all analyzed using multivariate logistic regressions.

This allowed the researchers to elucidate the drivers of ZVF consumption at every geographic and temporal scale.

Study findings

Globally, 45.7% of all children aged 6-23 months were found to have not consumed fruits and vegetables the preceding day. These values corroborated previous MDD estimates and elucidated that West and Central Africa (WCAFR) nations were the worst affected (56.1%). In comparison, Latin America and the Caribbean (LAC) showed the best food practices, with ZVF consumption found in only 34.5% of children.

Seasonal data was a confounding variable, varying in some nations but without significant ZVF correlations across years. Of the 38 countries included in the ZVF-over-time analyses, 16 showed positive trends (reduction in ZVF over time), 8 showed negative trends, and 14 remained unchanged between surveys. Of all 64 nations surveyed, Peru showed the best ZVF value of only 20%.

Analyses elucidated that age is the most important characteristic across all regions – as age increased, ZVF reduced.

In contrast, education levels were the primary correlate for ZVF in mothers – the higher the mother's education level, the lower the ZVF consumption of her children, irrespective of her age. The mothers' media exposure and employment status also significantly reduced ZVF values in their children.

Wealth and residence location (rural vs. urban) were the final determinants of ZVF, with wealthier households and urban residents consistently depicting lower ZVF levels than their poorer or rural counterparts, irrespective of region.

Climatic conditions, while statistically significant, were found to have odds ratios (ORs) close to one, implying small to no effects on ZVF compared to wealth, residence, and the mother's characteristics.

Conclusions

This study represents the first ZVF analyses for LMICs and the first global-scale research on IYCF. The results establish the link between education, multimedia exposure, and income as primary determinants of ZVF in children.

This paints a promising picture as it implies that management policies at regional and national scales could reduce or even reverse ZVF consumption, consistent with predictions made for other MDDs.

An enabling environment can be achieved through policy changes, such as taxation of less healthy foods and subsidizing healthier food or other policies to help mitigate poor households experiencing sharp increases in food costs due to economic shocks."

Seasonality and climate were elucidated as having a present, yet the negligible impact on ZVF consumption, indicating that economic upliftment, outreach programs, and education policies will be the main drivers in combating ZVF and its life-long effects on individuals' health.

A significant limitation of the study was that it failed to capture within-nation variation. Thus, caution must be exercised when generalizing nation results to specific regions within a said nation. Errors introduced during surveying might also have confounded effects, with both over-reporting and underreporting being potential sources of the same.

Despite these limitations, the new ZVF indicator is a useful tool for advocacy and monitoring diet quality among young children. Vegetable and fruit consumption is a critical component of young children's diets and provides important micronutrients that support healthy growth and development."