Iron
Last updated: August 9, 2026
Benefits
Carries oxygen in the blood and supports energy production. Iron from animal foods (heme) absorbs more easily than plant iron.
How much you need
Recommended daily amounts by life stage, per NIH and NASEM Dietary Reference Intakes. Where the evidence hasn't been enough to set a full RDA (Recommended Dietary Allowance), NASEM sets an AI (Adequate Intake) instead — both are shown together below.
| Life stage | RDA / AI |
|---|---|
| Children 1–3 | 7 mg |
| Children 4–8 | 10 mg |
| Boys 9–13 | 8 mg |
| Girls 9–13 | 8 mg |
| Males 14–18 | 11 mg |
| Females 14–18 | 15 mg |
| Men 19–50 | 8 mg |
| Women 19–50 | 18 mg |
| Men 51–70 | 8 mg |
| Women 51–70 | 8 mg |
| Men 71+ | 8 mg |
| Women 71+ | 8 mg |
| Pregnancy 14–18 | 27 mg |
| Pregnancy 19–50 | 27 mg |
| Lactation 14–18 | 10 mg |
| Lactation 19–50 | 9 mg |
Upper limit
This limit applies to total Iron intake — food and supplements combined.
| Life stage | Tolerable upper limit |
|---|---|
| Children 1–3 | 40 mg |
| Children 4–8 | 40 mg |
| Boys 9–13 | 40 mg |
| Girls 9–13 | 40 mg |
| Males 14–18 | 45 mg |
| Females 14–18 | 45 mg |
| Men 19–50 | 45 mg |
| Women 19–50 | 45 mg |
| Men 51–70 | 45 mg |
| Women 51–70 | 45 mg |
| Men 71+ | 45 mg |
| Women 71+ | 45 mg |
| Pregnancy 14–18 | 45 mg |
| Pregnancy 19–50 | 45 mg |
| Lactation 14–18 | 45 mg |
| Lactation 19–50 | 45 mg |
Day-to-day intake above this amount can cause constipation, nausea, and stomach pain — the digestive effects this limit is set by — and can reduce how much zinc the body absorbs. A large amount taken at once is a different and more urgent problem that needs immediate medical attention. People with hemochromatosis absorb iron more readily and are more susceptible to build-up.
Best food sources
| Serving | ||
|---|---|---|
| Red meat and liver | — | — |
| Oysters and clams | — | — |
| Lentils and beans | — | — |
| Tofu and pumpkin seeds | — | — |
| Fortified cereals | — | — |
Absorption & caution
Absorption: Iron absorbs best on an empty stomach, though a little food can ease the stomach upset it sometimes causes. Coffee, tea, and calcium-rich foods consumed at the same time reduce absorption.
Caution: More iron isn't always better. Men and post-menopausal women rarely need extra, and people with hemochromatosis (iron overload) should avoid iron supplements. Take an iron supplement only for a known need, ideally guided by bloodwork.
Pairings
Works well with
- Vitamin C — Vitamin C boosts iron absorption, especially iron from plant foods.
Competes with
Body systems & goals
Body systems it supports
- Hair & Nails — Hair and nails are among the last places your body spends nutrients, so they often show the strain first. A steady supply of these supports strength and healthy growth. (established evidence)
- Brain — Your brain runs on a steady supply of these nutrients to think, focus, and hold a mood. Keeping them topped up supports the mental clarity that's often the first thing to fade when you're worn down. (established evidence)
- Reproductive — Hormone balance and steady energy underpin a healthy reproductive system. These nutrients support your body's normal function in this area, especially when life has left you depleted. (emerging evidence)
- Thyroid — Your thyroid sets the pace for your whole metabolism, and it needs these nutrients to make its hormones. Supporting them helps your body maintain steady energy and temperature. (emerging evidence)
Goals it supports
- Energy & stamina (established evidence)
- Athletic performance (established evidence)
- Cycle support (established evidence)
- Plant-based diet (established evidence)
Frequently asked questions
How much Iron do adult women need per day?
Adult women (19–50) need 18 mg of Iron per day, per NIH/NASEM Dietary Reference Intakes.
How much Iron do adult men need per day?
Adult men (19–50) need 8 mg of Iron per day, per NIH/NASEM Dietary Reference Intakes.
Does pregnancy change how much Iron you need?
Yes — during pregnancy (ages 19–50) the recommended amount rises to 27 mg per day, compared with 18 mg for non-pregnant adult women.
Is there an upper limit for Iron?
Yes — for adults 19–50, the tolerable upper limit is 45 mg. Day-to-day intake above this amount can cause constipation, nausea, and stomach pain — the digestive effects this limit is set by — and can reduce how much zinc the body absorbs. A large amount taken at once is a different and more urgent problem that needs immediate medical attention. People with hemochromatosis absorb iron more readily and are more susceptible to build-up.
What foods are highest in Iron?
Good sources include Red meat and liver, Oysters and clams, Lentils and beans, Tofu and pumpkin seeds, and Fortified cereals.
How Tavita handles this
Tavita logs Iron from both the food you eat and the supplements you take, adding both into one running daily total. It warns you before you reach the tolerable upper limit, counting your combined intake from food and supplements.
Sources
Figures on this page come from the NIH Office of Dietary Supplements fact sheets and the National Academies of Sciences, Engineering, and Medicine (NASEM) Dietary Reference Intake tables — the same dataset that powers the Tavita app. They were independently re-verified by blind re-derivation on August 9, 2026. See the methodology page for how this library is built and kept current.
Tavita is not a medical provider. This page is educational information, not medical advice — talk to your clinician before changing your supplement or medication routine.