Can red meat help women improve iron levels? New study suggests modest benefits

Can red meat help women improve iron levels? New study suggests modest benefits

Can eating more steak and burgers fix iron deficiency? New research shows red meat's power to boost hemoglobin levels in women - but there's a catch.

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

The review article published in the journalNutritional ReviewsProvides useful information on nutritional interventions to control iron deficiency.

background

Iron deficiency is the most common 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.

The researchers noted that in addition to iron, red meat provides other nutrients such as zinc and B vitamins that may contribute to improvements in hemoglobin, although these nutrients' ability to influence iron status remains unclear.

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

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

Oral iron supplementation is the most commonly used intervention to prevent and treat iron deficiency. However, this intervention has many side effects, including nausea, vomiting, constipation and diarrhea, often leading to treatment discontinuation.

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

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

Review design

The researchers searched various electronic databases to identify relevant intervention studies published up to October 2024. This review systematically analyzed ten studies involving 397 adult participants (original news story 397,323) aged 18 to 70 years who reported increased red meat intake for at least four weeks as an intervention and at least one iron status biomarker (ferritiner, ferritin, and at least one iron status biomarker).

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

Observations

Participants ate up to 1.8kg of red meat weekly - more than 20 servings - but the benefits did not necessarily increase with higher intake, suggesting that more is not always better.

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

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

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

In the meta-analysis, no significant effect of intervention on serum ferritin levels was found unless interventions lasted ≥8 weeks, with ferritin levels increasing by +2.27 µg/L after 8–16 weeks and +5.62 µg/L beyond 16 weeks. Similarly, ferritin results 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, particularly for people with iron deficiency anemia (IDA).

In this regard, existing evidence suggests that the synergistic effects of red meat micronutrients, including iron, zinc, selenium, vitamins B6 and B12, and folate, may increase hemoglobin synthesis.

Moderator analysis revealed a greater improvement in hemoglobin levels in women than in men. The hormone -hepcidin, which regulates iron homeostasis, improves iron absorption at lower concentrations in women. In addition, there is a higher risk of iron deficiency due to menstrual blood loss and pregnancy-related demands, which may explain the gender difference in post-intervention hemoglobin status observed in the meta-analysis.

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

Participants who rarely ate red meat before the trial saw the hemoglobin boost—a “novelty effect” for dietary shifts—compared to regular consumers.

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

A notable exception was a study that reported improvements in iron status in 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 across populations responds to iron deficiency.

These inconsistencies in results highlight the need for future studies that focus 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 longer periods of intervention may be required to detect a beneficial effect of increased red meat intake on markers of iron status. Further studies with longer intervention periods are needed to better understand the effects of dietary iron interventions on iron status.

In addition, all included studies were rated as having at least “some concern” for risk of bias, and one study was rated as having “high risk of bias,” limiting the strength of the evidence.

Studies using diets rich in vitamin C as well as red meat recorded 15% greater hemoglobin gains, suggesting untapped combinatorial strategies.

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

Although increased red meat intake results in modest improvements in iron status, the extent to which such increases are clinically meaningful remains to be determined. Furthermore, serum ferritin, as an acute phase protein, may be influenced by inflammation, which was not consistently controlled in the included studies and may confound ferritin as a marker of iron stores.

While hemoglobin and ferritin have been the primary focus, other markers such as serum iron, transferrin saturation, and soluble transferrin receptor have also been studied, but yielded mixed or negative results, complicating interpretations.

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

Diploma

The current review results 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, particularly hemoglobin, the observed biomarker changes were modest and may not result in meaningful clinical outcomes.

Importantly, oral iron supplementation is still considered superior for individuals with iron deficiency anemia, although dietary approaches such as red meat intake may provide a complementary strategy, particularly for long-term maintenance of iron status.

Future research should focus on longer interventions in iron deficiency populations, controlling for confounding factors such as inflammation and habitual diet, and evaluating clinical outcomes beyond biomarker improvements.

Sources: