Can eating more steak and burgers fix iron deficiency? New research reveals red meat’s power to lift hemoglobin levels in women—but there’s a catch.

Study: Effect of Increasing Red Meat Intake on Iron Status in Adults with Normal and Suboptimal Iron Status: A Systematic Literature Review and Meta-Analysis of Intervention Studies. Image Credit: Elena Eryomenko / Shutterstock

Researchers at Dublin City University, Ireland, conducted a systematic review and meta-analysis of intervention studies that investigated the effect of increased red meat intake on iron status in adults.

The review article published in the journal Nutrition Reviews provides useful information on dietary interventions for controlling iron deficiency.

Background

Iron deficiency is the most prevalent nutrient deficiency worldwide, affecting approximately 25% of the world’s population. It is associated with a range of health adversities, including fatigue, cognitive impairment, and reduced physical ability and productivity.

Most importantly, iron deficiency is a leading cause of anemia, which, in severe form, can cause lethargy, breathlessness, impaired growth and development, and adverse pregnancy outcomes.

Factors that increase the risk of iron deficiency include consuming diets with low bioavailable iron, performing high-intensity aerobic exercise for a long duration, having heavy menstrual bleeding, and having reduced iron absorption.

Oral iron supplementation is the most commonly used intervention for preventing and treating iron deficiency. However, this intervention has many side effects, including nausea, vomiting, constipation, and diarrhea, which often lead to treatment discontinuation.

Improving iron levels through dietary interventions is a potential alternative to prevent iron deficiency. Red meat, such as beef, pork, and lamb, is a rich source of dietary iron, especially the most bioavailable heme iron.

The current systematic review aimed to identify, critically appraise, and meta-analyze the findings of available intervention studies that investigated the effects of increased red meat intake on iron status in adults with normal and suboptimal iron status.

Review Design

Researchers searched various electronic databases to identify relevant intervention studies published until October 2024. This review systematically analyzed ten studies that involved 397 adult participants (original news story incorrectly stated 397,323) aged 18 to 70, considered increased red meat intake for at least four weeks as an intervention, and measured at least one iron status biomarker (ferritin, hemoglobin, and transferrin saturation).

Most participants (81%) were women, predominantly of childbearing age, a group at higher risk for iron deficiency.

Observations

The ten studies included in the review involved 397 participants. The most frequently reported iron status biomarkers in these studies were serum levels of ferritin (the major iron storage protein) and hemoglobin (a functional biomarker).

The quantity of red meat consumed by participants each week ranged between 255 grams (cooked weight) and 1841 grams (cooked weight), and the duration of intervention lasted between 8 and 52 weeks.

The meta-analysis of included studies revealed that increased red meat consumption can significantly increase serum hemoglobin levels in adults. However, the meta-analysis found substantial heterogeneity in hemoglobin results (I² = 96.3%), indicating a high level of variability between studies.

No significant effect of the intervention on serum ferritin level was found in the meta-analysis unless interventions lasted ≥8 weeks, where ferritin levels increased by +2.27 µg/L at 8–16 weeks and +5.62 µg/L beyond 16 weeks. Similarly, ferritin outcomes showed high heterogeneity (I² = 91.4%), which may affect the reliability of pooled estimates.

Despite these improvements, the review noted that these increases may be too small to be clinically meaningful, especially for individuals with iron deficiency anemia (IDA).

In this context, existing evidence suggests that the synergistic actions of red meat micronutrients, including iron, zinc, selenium, vitamins B6 and B12, and dietary folate, might increase hemoglobin synthesis.

The moderator analysis revealed greater improvement in hemoglobin level in women than in men. The hormone hepcidin, which regulates iron homeostasis, helps improve iron absorption at lower concentrations in women. Additionally, women are at higher risk of iron deficiency due to menstrual blood loss and pregnancy-related demands, which might explain the gender-wise difference in post-intervention hemoglobin status observed in the meta-analysis.

Regarding ferritin levels, the moderator analysis revealed that red meat can significantly improve serum ferritin levels when consumed for ≥8 weeks. Moreover, the analysis showed that ferritin improvements were more pronounced when interventions lasted longer than 16 weeks.

Most of the studies included in this meta-analysis focused on women of childbearing age. This might be because these women are at higher risk of developing iron deficiency because of the increased requirement of iron during pregnancy. However, while some individual studies reported that participants with lower baseline iron status showed greater improvements in serum ferritin and hemoglobin, the meta-analysis did not identify baseline iron status as a statistically significant moderator overall.

One notable exception was a study reporting improvements in iron status among obese women with normal baseline iron status. These improvements were observed in the context of a high-protein, weight loss dietary intervention, suggesting that increased red meat intake may have benefits beyond iron-deficient populations.

These discrepancies in findings highlight the need for future studies focusing exclusively on individuals with low iron status.

Regarding ferritin levels, the meta-analysis showed that red meat intake for a longer duration is beneficial in terms of increasing serum ferritin levels. For example, interventions lasting ≥16 weeks increased ferritin by 5.62 µg/L.

These observations suggest that more extended intervention periods may be necessary to see a beneficial effect of increased red meat intake on markers of iron status. More studies using longer intervention periods are needed to better understand the impact of diet-based interventions on iron status.

Furthermore, all included studies were assessed as having at least “some concerns” for risk of bias, and one study was rated at “high risk of bias,” which limits the strength of the evidence.

Notably, control groups in the included studies followed diverse diets, including habitual low-bioavailable iron diets, vegetarian diets, or multivitamin-supplemented regimens, which may influence the generalizability of results.

Although increased red meat intake leads to a slight improvement in iron status, the extent to which such increases are clinically meaningful remains to be established. Moreover, serum ferritin, as an acute-phase protein, can be influenced by inflammation, which was not consistently controlled for in the included studies and may confound ferritin as a marker of iron stores.

Additionally, while hemoglobin and ferritin were the primary focus, other markers such as serum iron, transferrin saturation, and soluble transferrin receptor were also examined but yielded mixed or negative results, complicating interpretations.

The review did not assess publication bias formally, but given the small number of included studies, the potential for such bias cannot be ruled out.

Conclusion

The current review findings are based on only ten studies. This limitation highlights the need for additional research in this area. Although increased red meat intake leads to a slight improvement in iron status, especially hemoglobin, the observed biomarker changes were modest and may not translate into meaningful clinical outcomes.

Importantly, oral iron supplementation is still considered superior for individuals with iron deficiency anemia, though dietary approaches like red meat intake may offer a complementary strategy, especially for long-term maintenance of iron status.

Future research should focus on longer interventions in iron-deficient populations, aim to control for confounders like inflammation and habitual diet, and evaluate clinical outcomes beyond biomarker improvements.