Iron: Food Sources & Daily Intake

Table of Contents

1. How to Read These Tables
2. Recommended Intakes & Upper Limits
3. Bioavailability & Absorption
4. Cooking & Storage
5. Vegetarian & Vegan Sources
6. Who Needs to Pay Attention
7. Key Research Papers
8. Connections
9. Featured Videos

How to Read These Tables

• Heme vs non-heme iron. The single most important thing about iron. Heme iron (animal foods — oysters, liver, red meat) is absorbed at roughly 15–35%. Non-heme iron (plants — beans, seeds, spinach, dark chocolate) is absorbed at only about 2–20% and is far more sensitive to what else is on the plate. The number on the table is the iron in the food, not the amount you keep.
• %DV vs your real target. The %DV column compares 100 g of the food against the U.S. Food and Drug Administration (FDA) Daily Value of 18 mg used on labels. Your personal target (the Recommended Dietary Allowance (RDA)) varies a lot: just 8 mg for men and post-menopausal women, but 18 mg for women 19–50 and 27 mg in pregnancy — see the second table.
• Per 100 g vs per serving. Per-100 g lets you compare foods fairly; the serving size shown beside each food is what you actually eat. Some foods (cocoa powder, molasses) look huge per 100 g but contribute modestly in a real spoonful, while a cup of beans or cooked spinach adds up nicely.

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Recommended Intakes & Upper Limits

Your personal target depends on age, sex and pregnancy. The Daily Value used for the %DV column above is a single label figure; the table below is the age-specific guidance.

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Bioavailability & Absorption

How much iron you actually absorb depends heavily on its form and on the rest of the meal. Heme iron from meat and seafood is absorbed well (roughly 15–35%) and is largely unaffected by other foods. Non-heme iron from plants is absorbed far less efficiently and is strongly influenced by meal companions. Vitamin C is the big helper: eating a vitamin-C food in the same meal (citrus, peppers, tomatoes, strawberries) can multiply non-heme absorption several-fold, which is why a squeeze of lemon on lentils or peppers in a bean chili raises the iron absorbed from the meal. A little meat, poultry or fish in the same meal also boosts the non-heme iron from any plant foods alongside it. Working the other way, phytates in whole grains, beans and seeds, polyphenols and tannins in tea, coffee and red wine, and high doses of calcium all reduce iron absorption — tea or coffee drunk between meals interferes less than tea or coffee drunk with them.

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Cooking & Storage

Iron stands up to heat far better than the fragile vitamins, so ordinary cooking does not destroy it. A few practical points still help: soaking, sprouting and fermenting beans, grains and seeds breaks down some of the phytates that block absorption, which is one reason sourdough, sprouted lentils and properly soaked beans treat your iron stores more kindly. Cooking acidic foods (like a tomato sauce) in a cast-iron pan measurably raises the iron content of the dish. And because cooked spinach packs down, a cooked portion delivers far more iron than the same volume of raw leaves.

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Vegetarian & Vegan Sources

Plant-based eaters can absolutely meet their iron needs, but it takes a little planning because plant iron is the harder-to-absorb non-heme form. The backbone is legumes (lentils, chickpeas, white and kidney beans), seeds (pumpkin, sesame), dark leafy greens and dark chocolate. The key habit is to pair iron-rich plants with a vitamin-C food in the same meal — beans with peppers and tomato, lentils with a squeeze of lemon, oatmeal with strawberries — which can dramatically raise how much you absorb. Tea and coffee taken between meals interfere less than tea and coffee taken with them. Because absorption is lower, some guidelines suggest vegetarians aim higher than the standard Recommended Dietary Allowance. People who are both plant-based and menstruating carry two of the main risks for low iron stores, which a blood test can show.

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Who Needs to Pay Attention

Iron deficiency is the most common nutritional deficiency in the world, and the groups most at risk are menstruating women (especially with heavy periods), pregnant women (whose needs jump to 27 mg/day), infants and young children, frequent blood donors, endurance athletes, and people with gut conditions that impair absorption. Deficiency progresses from low stores to full iron-deficiency anemia — fatigue, pallor, breathlessness, cold hands, brittle nails, and sometimes odd cravings for ice or starch. The opposite caution matters too: iron is one of the few minerals the body cannot easily get rid of, so it is possible to overload. In people with hereditary hemochromatosis (an inherited condition causing excess iron absorption), and in men and post-menopausal women generally, iron supplements taken without a blood-test-proven deficiency add to stores the body cannot shed — excess iron accumulates in the liver, heart and pancreas and causes damage over time. Iron supplements are also a leading cause of accidental poisoning in young children.

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Key Research Papers

1. NIH Office of Dietary Supplements — Iron Fact Sheet (DV, RDA, UL)
2. Linus Pauling Institute — Iron Micronutrient Information Center
3. Hurrell R, Egli I (2010). Iron bioavailability and dietary reference values. American Journal of Clinical Nutrition;91(5):1461S-1467S. — PubMed PMID: 20200263
4. Hallberg L, Brune M, Rossander L (1989). The role of vitamin C in iron absorption. International Journal for Vitamin and Nutrition Research Supplement;30:103-108. — PubMed PMID: 2507689

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Connections

• All Minerals
• Iron (Main Page)
• Iron Benefits
• Iron History
• Vitamin C (boosts non-heme iron)
• Copper (needed to use iron)
• Zinc
• Lentils
• Spinach

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Featured Videos

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