BMJ Nutr Prev Health
Guava juice may boost iron supplement effects in anemia
Clinical takeaway: Pairing iron supplements with vitamin C–rich foods may amplify hemoglobin gains; guava juice is one option.
Iron deficiency anemia is common in menstruating adolescents and pregnant patients. Oral iron supplementation is the standard therapy. Vitamin C enhances absorption of non-heme iron, and guava is a particularly rich source, with roughly four times the vitamin C per 100 g of oranges. Small Indonesian trials had reported hemoglobin gains after guava juice consumption, but the findings hadn't been pooled.
In five studies directly comparing guava juice plus iron supplementation against iron supplementation alone (102 participants per arm), the combination produced a hemoglobin gain 1.29 g/dL greater than supplements alone.
Across 12 quantitative studies involving 235 women and girls, the pooled before-and-after difference after guava juice consumption was 1.71 g/dL. Gains averaged 1.52 g/dL among teenage girls and 1.84 g/dL among pregnant women. The authors note that a 1 to 2 g/dL shift can move patients from mild or moderate anemia into the non-anemic range, with downstream effects on fatigue and cognitive function.
The systematic review covered clinical trials and quasi-experimental studies published in English from 2000 onward. Seventeen studies met inclusion criteria: 15 quasi-experimental and 2 randomized controlled trials. Six enrolled teenage girls and 11 enrolled pregnant women. Nine evaluated guava juice plus iron supplementation; the rest examined guava juice alone or against other comparators.
"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," said Sumantra Ray, chief scientist and executive director of the NNEdPro Global Institute for Food, Nutrition and Health.
Source: Mansoor J. BMJ Nutr Prev Health. 2026 May 26. Effect of guava juice intake on haemoglobin levels in Indonesian females: a systematic review and meta-analysis