Iron level chart for adults
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Iron Levels in Adults: A Comprehensive Overview
Iron Status in Adults: Key Metrics and Trends
Hemoglobin and Serum Ferritin Levels
Iron status in adults is commonly assessed using hemoglobin (Hb) concentration and serum ferritin (SF) levels. In a study conducted in Finland, the mean Hb concentration was found to be 133 ± 12 g/L for women under 50 years, 137 ± 10 g/L for women aged 50 and above, and 150 ± 10 g/L for men. Serum ferritin levels, which indicate iron stores, were 32 ± 30 µg/L in younger women and 62 ± 59 µg/L in older women, with 20% of younger women showing iron depletion (SF < 12 µg/L).
In the United Kingdom and Ireland, mean SF concentrations were reported as 140.7 µg/L in men, 49.4 µg/L in premenopausal women, and 96.7 µg/L in postmenopausal women. These values highlight the variability in iron stores across different age and gender groups.
Iron Intake and Bioavailability
Iron intake varies significantly among adults. In Finland, the mean daily iron intake was 10 mg for women and 13 mg for men, with cereals and meat being the primary dietary sources. In the Netherlands, average iron intake exceeded the recommended daily allowance for all groups except women aged 20-49, where intake was 23% below the recommendation.
Bioavailability of dietary iron is influenced by the type of iron consumed and other dietary factors. A model developed in the UK predicts that dietary iron absorption decreases as serum ferritin levels increase, with absorption rates ranging from 22.3% to 11.6% in men and 27.2% to 10.6% in premenopausal women, depending on their SF levels.
Iron Requirements in Special Populations
Menstruating women have higher iron requirements due to menstrual blood losses. Calculations indicate that adult women need 2.84 mg of absorbed iron per day, translating to dietary requirements of 18.9 mg/day when considering a 15% bioavailability. Teenagers have even higher requirements due to growth needs, with dietary requirements estimated at 21.4 mg/day.
Impact of Diet on Iron Status
Vegetarian diets, which exclude meat and seafood, can lead to lower iron stores due to the absence of highly bioavailable heme iron and the presence of inhibitors of non-heme iron absorption in plant foods. A meta-analysis found that vegetarians have significantly lower serum ferritin levels compared to non-vegetarians, with the effect being more pronounced in men.
Iron Deficiency and Health Implications
Iron deficiency is a common issue, particularly among women. In the National Health and Nutrition Examination Survey (NHANES) conducted in the United States, 13.7% of women were found to be iron deficient, with 4.0% having iron deficiency anemia. Iron deficiency was associated with higher A1C levels, indicating a potential impact on glycemic control.
Conclusion
Iron status in adults varies widely based on age, gender, and dietary habits. While men generally have adequate iron stores, women, especially those of reproductive age, are at higher risk of iron deficiency. Dietary choices, particularly the inclusion of meat, play a crucial role in maintaining adequate iron levels. Regular monitoring and dietary adjustments are essential to prevent iron deficiency and its associated health risks.
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