Iron-deficiency anemia care uses 40–100 mg elemental iron alternate-day to daily for 8–12+ weeks with tests and supervision
Reviewed · Published
Iron
Required for oxygen transport, electron transfer, and enzymes, but excess is harmful.
Established functions
- Required for oxygen transport, electron transfer, and enzymes, but excess is harmful.
Dietary sources
- lean meat
- clams
- lentils
Claims and evidence
Claims that Iron alone prevents or treats disease, or invariably improves health without deficiency, are unsupported.
Japanese reference amounts
- Japanese adults (age and sex as specified): Adult men 7.0–7.5 mg/day; menstruating women 10.0–10.5 mg/day (RDA)
Amounts studied
- Iron-deficiency anemia care uses 40–100 mg elemental iron alternate-day to daily for 8–12+ weeks with tests and supervision
Tolerable upper limits
- Adults: 40 mg/day
Forms and bioavailability
Supplement forms: ferrous bisglycinate, ferrous sulfate
- Heme iron is better absorbed; vitamin C enhances nonheme iron while tea and phytate inhibit it.
Safety and interactions
Adverse effects
- constipation
- nausea
- dark stool; overdose can be fatal
Medicine and nutrient interactions
- levothyroxine, antibiotics, calcium, antacids
Contraindications and cautions
- Do not use with hemochromatosis or unexplained anemia; keep away from children.
Practical selection
- Compare Iron amount per serving, form, allergens, and batch testing; prefer a single-ingredient product suited to the intended use.
Sources and review
- Dietary Reference Intakes for Japanese (2025)Ministry of Health, Labour and Welfare (Japan)
- NIH ODS mineral fact sheetsNIH Office of Dietary Supplements
Daiki Minaki (editorial and evidence review) ·