Clinical Research Directory

Inclusion Criteria: * Normal weight group 1. Aged 40-50 years 2. Normal weight (BMI 18.5-22.9 kg/m²) 3. Hb ≥12.0 g/dL and inflammation-adjusted SFa \<50.0 µg/L 4. CRP \<5.0 mg/L 5. Normal hemoglobin typing 6. Plans to reside in the study area for \>2 years * Overweight/obese group 1. Aged 40-50 years 2. Overweight or obese \[Body Mass Index (BMI) ≥25.0 kg/m²\] - the BMI cut-off follows the agreement of countries under the Coordinated Research Project (CRP) E43038 "Using the iron isotope dilution technique to assess the influence of inflammation on long-term iron absorption and loss," supported by the IAEA 3. Hemoglobin (Hb) ≥12.0 g/dL and inflammation-adjusted serum ferritin (SFa) \<50.0 µg/L 4. C-reactive protein (CRP) between 5.0-25.0 mg/L 5. Normal hemoglobin typing 6. Plans to reside in the study area for \>2 years Exclusion Criteria: * Normal weight group 1. Having serious medical conditions such as cancer, chronic kidney disease, chronic liver disease, or chronic heart failure 2. Having metabolic NCDs (e.g., diabetes, hyperlipidemia, hypertension) requiring hospitalization 3. Pregnant, breastfeeding, or planning pregnancy during the study 4. Chronic infectious disease (e.g., tuberculosis, AIDS) 5. Regular use of anti-inflammatory or other medications (except contraceptives and acne medication) 6. Taking vitamin or mineral supplements during or within two weeks prior to the study 7. Participating in a weight-loss program 8. Known intolerance to iron supplements (e.g., vomiting, diarrhea, abdominal pain, bloating, nausea, or allergic reactions such as rash, breathing difficulty, chest tightness, facial or lip swelling) 9. Blood transfusion, blood donation, or significant blood loss during the study or within 6 months before enrollment 10. Heavy menstrual bleeding (\>80 mL/day, calculated from menstrual record) * Overweight/obese group 1. Obesity class II (BMI ≥35.0 kg/m²) with high health risk 2. Having serious medical conditions such as cancer, chronic kidney disease, chronic liver disease, or chronic heart failure 3. Having metabolic noncommunicable diseases (e.g., diabetes, hyperlipidemia, hypertension) requiring hospitalization 4. Pregnant, breastfeeding, or planning pregnancy during the study 5. Chronic infectious disease (e.g., tuberculosis, AIDS) 6. Regular use of anti-inflammatory or other medications (except contraceptives and acne medication) 7. Taking vitamin or mineral supplements during or within two weeks prior to the study 8. Participating in a weight-loss program 9. Known intolerance to iron supplements (e.g., vomiting, diarrhea, abdominal pain, bloating, nausea, or allergic reactions such as rash, breathing difficulty, chest tightness, facial or lip swelling) 10. Blood transfusion, blood donation, or significant blood loss during the study or within 6 months before enrollment 11. Heavy menstrual bleeding (\>80 mL/day, calculated from menstrual record)