Regular guava juice consumption may prove a readily accessible and affordable addition to helping lower the risk of anaemia in women in low and middle income countries, suggests a synthesis of the available evidence, published in the open access journal BMJ Nutrition Prevention & Health.
A combination of guava juice and iron supplements is more effective than the supplements alone for boosting haemoglobin levels, the pooled data indicate, prompting the researchers to suggest its inclusion in dietary counselling for anaemia prevention in countries with a high prevalence of the condition.
Iron deficiency anaemia is very common in teenage girls and pregnant women in low and middle income countries, putting them at heightened risk of ill health and death, note the researchers.
In many Asian regions, guava fruit is a rich, affordable source of vitamin C, which boosts uptake of dietary iron from plant sources, they add. The fruit contains up to 4 times as much vitamin C per 100 g as oranges, and also provides vitamin A, folate, dietary fibre, and modest amounts of iron, they point out.
While several small Indonesian studies have reported increases in haemoglobin after drinking the juice, the findings haven't been synthesised to establish its overall effectiveness, they explain.
The researchers therefore scoured research databases for relevant clinical trials and quasi-experimental studies published in English from 2000 onwards.
They found 17 eligible studies, 15 of which were quasi-experimental trials, and 2 of which were randomised controlled trials. Six studies focused on teenage girls and 11 involved pregnant women. Most (9) evaluated the effects of guava juice plus iron supplementation.
The results of 12 quantitative studies involving 235 women and teenage girls were synthesised. The pooled average difference in haemoglobin levels was 1.71 g/dl, overall, indicating a significant improvement after guava juice consumption.
Further detailed analysis showed average differences after drinking the juice of 1.52 g/dl among teenage girls and 1.84 g/dl among pregnant women.
In the five studies directly comparing guava juice and iron supplementation combined and iron supplementation alone (102 participants in each group), the average difference was 1.29 g/dl greater with the guava juice combination.
"An increase of 1–2 g/dl may shift individuals from mild or moderate anaemia to non-anaemic categories, improving fatigue, cognitive function, and productivity outcomes," suggest the researchers.
They highlight various limitations to their findings, including the fact that all the studies were carried out solely in Indonesia, and the wide variability in study design, intervention duration, guava variety, dose and participant characteristics.
The predominance of quasi-experimental designs also restricts causal inference, and the lack of long term follow up precludes assessment of the sustainability of any improvements in haemoglobin levels, they emphasise.
"Integrating guava juice into school nutrition programmes, antenatal care packages, or community health initiatives could represent a feasible approach to address mild-to-moderate anaemia, aligning with the United Nations' Decade of Action on Nutrition (2016–2025), which emphasises dietary diversification and locally sourced nutrient-rich foods," they point out.
"Given its nutritional richness, affordability, and cultural acceptance across Asia, guava juice offers a promising low-cost intervention. Strengthening local supply chains, standardising formulations and embedding such dietary approaches within public health nutrition programmes could collectively contribute to more sustainable anaemia control," they add.
"This study builds on the established role of dietary sources high in vitamin C to enhance iron absorption and improve the effectiveness of iron supplementation," comments Professor Sumantra Ray, chief scientist & executive director, NNEdPro Global Institute for Food, Nutrition and Health, which co-owns BMJ Nutrition Prevention & Health.
"But quasi-experimental research, the wide variation in study design, small sample sizes, and limited length of follow-up mean that caution is required when interpreting the findings. Without further rigorous research, defining the best therapeutic dose and period of use, guava juice can't be recommended as an alternative to conventional treatment in those at risk of iron deficiency anaemia," he adds.
