Iron Deficiency Statistics: Global Data, Demographics, and Research Summary
Iron deficiency is the most prevalent nutritional deficiency worldwide. This data page compiles the key statistics, demographic breakdowns, and research findings that journalists and health writers cite most frequently.
012 billion people worldwide are iron deficient — the most prevalent nutritional deficiency globally
021.2 billion have iron deficiency anemia (Stage 3); 800 million have depleted stores without anemia
0330% of non-pregnant women of reproductive age are iron deficient globally
04The U.S. has approximately 10 million iron deficient people and 5 million with iron deficiency anemia
05Non-heme iron (plant-based) absorption: 3 to 8%. Heme iron (animal): 14 to 18%
Global Iron Deficiency Prevalence
Iron deficiency is the most common nutritional deficiency worldwide, affecting populations across all income levels — though burden is disproportionately concentrated in low- and middle-income countries. The following data is sourced from WHO global nutrition reports and peer-reviewed epidemiological studies.
Global iron deficiency prevalence by region and demographic group
Population group
Global prevalence
Notes
All people worldwide
~2 billion (25 to 30% of global population)
Includes all stages of iron deficiency
Iron deficiency anemia specifically
~1.2 billion (15% of global population)
Stage 3 — hemoglobin reduced
Children under 5 years
42% globally
Highest burden in sub-Saharan Africa and South Asia
Pregnant women globally
38 to 52%
Iron requirements nearly double during pregnancy (27 mg/day)
Non-pregnant women of reproductive age
~30% globally; 9 to 12% in high-income countries
Monthly blood loss is the primary driver
Adult men globally
2 to 4%
GI blood loss is most common cause when it occurs
Post-menopausal women
Similar to adult men (2 to 4%)
Menstrual loss eliminated; GI causes dominant
Adolescent girls (15 to 19)
15 to 25% in many regions
High growth demands + menstrual onset
Iron Deficiency Statistics: United States
Iron deficiency prevalence in the United States by demographic group (NHANES data)
Demographic group
Iron deficiency prevalence
Iron deficiency anemia prevalence
Women 20 to 49 years
9 to 12%
2 to 5%
Girls 12 to 19 years
9 to 11%
2 to 3%
Children 1 to 5 years
7%
3%
Pregnant women
18%
5%
Men 20 to 49 years
<2%
<1%
Adults over 60 years
3 to 5%
10 to 12% (anemia from multiple causes)
Total U.S. population iron deficient
~10 million people
~5 million with anemia
Iron Absorption: Key Data Points
Iron absorption rates by food type, enhancers, and inhibitors
Scenario
Iron absorption rate
Notes
Heme iron (meat, poultry, fish)
14 to 18% of dietary iron
Uses heme transporter — not affected by most dietary inhibitors
Non-heme iron (plants, supplements) — baseline
3 to 8% of dietary iron
Uses DMT-1 transporter — highly regulated by body iron status
Non-heme iron + vitamin C (50 mg) at same meal
2 to 4x higher absorption
Ascorbic acid reduces ferric to absorbable ferrous form
Non-heme iron + coffee or tea at same meal
39 to 60% reduction
Polyphenols form insoluble iron complexes
Non-heme iron + calcium (300 mg) at same meal
30 to 50% reduction
Calcium competes with iron at intestinal transporter
Non-heme iron + phytates (whole grains) at same meal
20 to 60% reduction
Phytic acid binds iron; fermentation reduces this effect
Ferrous iron supplements — empty stomach
30 to 40% absorbed
Best absorbed; GI side effects more common
Ferrous iron supplements — with food
20 to 30% absorbed
Better tolerated; slightly reduced absorption
Ferric iron supplements
10 to 20% absorbed
Less bioavailable; newer chelated forms (bisglycinate) may be similar to ferrous
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Questions, answered.
How many people worldwide have iron deficiency?
Iron deficiency affects an estimated 2 billion people globally, making it the most common nutritional deficiency on Earth. Of these, approximately 1.2 billion have iron deficiency anemia (the more severe stage where hemoglobin is also reduced). The remaining 800 million have depleted iron stores without yet developing anemia.
What percentage of women are iron deficient?
Globally, approximately 30 percent of non-pregnant women of reproductive age are iron deficient. In low-income countries, this rises to 36 to 47 percent. In high-income countries, 9 to 12 percent of menstruating women are iron deficient. Post-menopausal women have much lower rates — similar to adult men at 2 to 4 percent.
How common is iron deficiency in the United States?
In the United States, approximately 10 million people are iron deficient. Of these, about 5 million have iron deficiency anemia. Women aged 20 to 49 have the highest prevalence at approximately 9 to 12 percent. Teenage girls (14 to 18 years) have prevalence rates of 9 to 11 percent. Adult men and post-menopausal women have rates below 4 percent.
What is the most common cause of iron deficiency?
The most common cause worldwide is inadequate dietary iron intake — especially in regions where meat consumption is low and plant-based iron sources dominate. In women of reproductive age in developed countries, the combination of menstrual blood loss and insufficient dietary compensation is the primary driver. Gastrointestinal blood loss (ulcers, colon cancer) is the most common cause in post-menopausal women and adult men.
What is the difference between iron deficiency and iron deficiency anemia in statistics?
Iron deficiency is a three-stage process: Stage 1 is depleted iron stores (ferritin below 12 to 30 ng/mL) with normal hemoglobin; Stage 2 is reduced iron availability for erythropoiesis (red blood cell production) with borderline hemoglobin; Stage 3 is iron deficiency anemia (reduced hemoglobin and small red blood cells). Most epidemiological statistics report Stage 3 (anemia), which means the global burden of iron deficiency is significantly underestimated — Stages 1 and 2 are far more prevalent than the anemia statistics suggest.
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