Iron
Carries oxygen in blood and supports energy, cognition, and immunity.
Why it matters
Iron is needed to make hemoglobin and myoglobin, so it helps carry and store oxygen. It also supports energy metabolism, cognition, growth, and immune function.
- Helps red blood cells carry oxygen.
- Supports muscle oxygen storage and energy production.
- Supports immune function, growth, and cognition.
If intake is too low
Iron deficiency is one of the most common nutrient gaps in the world. It can cause iron deficiency anemia, fatigue, reduced work capacity, and problems with attention or development.
- Fatigue, weakness, and shortness of breath.
- Iron deficiency anemia.
- Reduced concentration, learning, or exercise capacity when deficiency persists.
If intake is too high
Too much iron can cause stomach pain, constipation, nausea, and organ damage. Accidental overdose is especially dangerous in children.
- Nausea, vomiting, or constipation.
- Iron overload can damage the liver and other organs.
- Accidental overdose in children can be a medical emergency.
Adult upper limit: 45 mg/day
The upper limit exists because excessive iron can be harmful even though deficiency is common.
Common food sources
Iron comes from both animal and plant foods, but the form in animal foods is absorbed more readily.
- Red meat, poultry, seafood, and organ meats
- Beans, lentils, tofu, spinach, and pumpkin seeds
- Fortified cereals and grain products
Who may need closer attention
Iron needs are higher in some life stages, and absorption varies a lot based on diet composition.
- Pregnant people and menstruating women
- Infants, young children, and teens in growth phases
- Vegetarians, vegans, and frequent blood donors
Use extra caution if
Small details change the risk picture with nutrients more than most people expect.
You are pregnant, menstruate heavily, donate blood often, or have hemochromatosis or another iron-overload condition. Iron is one of the nutrients where the right dose is very personal.
Supplement and label notes
Useful context when this nutrient shows up across more than one product.
- Common forms include ferrous sulfate, ferrous gluconate, and ferrous fumarate.
- Vitamin C can improve absorption, while calcium, tea, coffee, and some medications can reduce it.
- Keep iron supplements out of reach of children.
Daily Value targets in SuppMap
These are the same label-style Daily Value targets used in the app.
Official references
These pages were used to draft the summaries on this guide.
Educational only. These pages are not a diagnosis or a substitute for personal medical care.
More guides
Keep moving through the rest of the Daily Value chart from here.