Iron RDA Table
| Age | Men mg | Women mg | Pregnancy mg | UL mg |
|---|---|---|---|---|
| 0-6 months | 0.27 (adequate intake - birth stores + milk) | 40 | ||
| 7-12 months | 11 | 40 | ||
| 1-3 years | 7 | 40 | ||
| 4-8 years | 10 | 40 | ||
| 9-13 years | 8 | 40 | ||
| 14-18 years | 11 | 15 | 27 | 45 |
| 19-50 years | 8 | 18 | 27 | 45 |
| 51 and older | 8 | 8 | - | 45 |
| Food | Serving | mg | %DV |
|---|---|---|---|
| Breakfast cereal, fortified | 1 serving | 18 | 100% |
| Oysters, eastern, cooked | 3 oz | 8 | 44% |
| White beans, canned | 1 cup | 8 | 44% |
| Dark chocolate, 45-69% cacao | 3 oz | 7 | 39% |
| Lentils, boiled | 1 cup | 6.6 | 37% |
| Tofu, firm | 1/2 cup | 3.4 | 19% |
| Spinach, boiled | 1/2 cup | 3 | 17% |
| Beef chuck roast | 3 oz | 2 | 11% |
| Company on the plate | Effect on plant (non-heme) iron | Move |
|---|---|---|
| Vitamin C (orange juice, peppers, tomatoes) | Multiplies absorption | Same plate |
| Meat, poultry or fish | Multiplies absorption (MPF factor) | Same plate |
| Tea or coffee (polyphenols) | Shuts absorption down | Keep 1-2 hours apart |
| Phytates (whole grains, legumes as-is) | Inhibits absorption | Soak, or offset with vitamin C |
Iron is the one nutrient where the table splits cleanly by sex: from age 19 to 50, the NIH recommended dietary allowance is 8 mg a day for men and 18 mg for women - a 2.25x gap that exists because menstrual blood loss is the body's only regular iron exit, and the RDA is engineered to cover it. Pregnancy multiplies the number again, to 27 mg, as blood volume expands by roughly half. Read the age-and-sex row, not the label's one-size number, and you already know more than the supplement aisle teaches.
The food ladder has a catch printed in it: the %DV column is calibrated to an 18 mg Daily Value - the old, women's-weighted standard - so a fortified cereal claiming 100% DV delivers exactly one 18 mg serving, and the oyster and white-bean rows that read 44% are delivering 8 mg each, nearly a full day for a man. That mismatch between label math and your actual row is the single most common iron miscalculation; the table below gives you milligrams so you can skip the conversion entirely.
The third table is the one almost nobody plans around: absorption. Heme iron from meat, poultry and fish enters at 15-35% efficiency; non-heme iron from plants and fortification scrapes in at 2-20%. The same bowl of lentils can roughly double or halve depending on company - vitamin C or meat on the plate multiplies non-heme uptake, while the polyphenols in tea and coffee and the phytates in whole grains shut it down. That is a scheduling problem, not a nutrition problem, and it is solvable by moving your coffee an hour or two away from the meal.
How to use
- Find your row: 8 mg covers men and everyone past 51; 18 mg applies to women 19-50; 14-18-year-olds sit at 11 (male) and 15 (female); pregnancy requires 27 mg while breastfeeding drops back to 9-10 mg. Then check the ceiling - 45 mg per day for teens and adults, 40 mg under 14 - before stacking any supplement on a multivitamin.
- Compose the plate by the absorption table: pair the lentil, bean, spinach or cereal rows with a vitamin C source (orange juice, bell peppers, tomatoes) or a little meat, and keep tea and coffee a hour or two clear of the meal - the polyphenols that make them bitter make your non-heme iron slide through unabsorbed.
- Self-screen by risk, not by vibe: pregnancy, heavy periods, frequent blood donation, infants after the 4-6-month birth-store runs out, and GI or heart conditions are the groups the NIH flags. Fatigue alone is not a diagnosis - ferritin falls before hemoglobin does, so ask for the storage number, not just the blood-count screen.
Frequently asked questions
How much iron do I need per day?
The NIH RDA: 0.27 mg is the adequate intake for infants under 7 months (covered by birth stores and milk), 11 mg from 7-12 months, 7-10 mg through childhood, 11 mg for teen boys and 15 mg for teen girls, 8 mg for adult men and women past 51, and 18 mg for women 19-50 - the menstruation premium. Pregnancy lifts the target to 27 mg; breastfeeding needs only 9-10 mg. These figures assume a mixed diet of heme and non-heme sources.
What foods are highest in iron?
Fortified breakfast cereal leads the table outright at 18 mg per serving - a full day at the old 18 mg Daily Value. Cooked oysters and canned white beans deliver about 8 mg, a cup of lentils 6.6 mg, dark chocolate 45-69% cacao about 7 mg per 3 ounces, firm tofu 3.4 mg per half cup, boiled spinach 3 mg, and beef chuck roast roughly 2 mg per 3 ounces. Notice the pattern: the plant rows beat the beef row, which is exactly why the absorption table matters more than the milligram table.
Can you take too much iron?
Yes - the tolerable upper limit is 40 mg per day up to age 13 and 45 mg for everyone older, and chronically exceeding it causes GI distress first (constipation, nausea, stomach pain) and organ damage at extremes. The sharpest warning on the label is for children: accidental overdose of iron-containing products is a leading cause of poisoning deaths in children under 6, which is why iron supplements ship in child-resistant packaging and dose lines are not suggestions.
Should I take iron with vitamin C - and skip coffee?
That is the practical core of the absorption table. Vitamin C converts non-heme iron into the form the gut takes up, multiplying absorption from the same meal; meat, poultry and fish do the same via the so-called MPF factor. Tea and coffee polyphenols and grain phytates do the opposite. You do not have to quit coffee - you have to schedule it: keep the cup an hour or two away from the iron-bearing meal and the supplement both.
What are the stages of iron deficiency?
Three, in order. Iron deficiency (ID) means stores are drained - ferritin drops while hemoglobin is still normal, and this stage is easy to miss on a standard blood count. Mild iron-deficiency anemia appears when hemoglobin slips below range and function starts to suffer. Moderate-to-severe IDA brings the textbook symptoms - fatigue, weakness, poor concentration, pallor - and by then stores are long gone. This ordering is why ferritin, not hemoglobin, is the early-warning number to request.
Who is most at risk of iron deficiency?
The NIH lists pregnant women, infants and young children, women with heavy menstrual bleeding, frequent blood donors, people with cancer, GI disease or heart failure - and, in the US population data, Black women at roughly 16% prevalence, about eight times the rate of white women. Vegetarians also run higher needs because non-heme iron absorbs at a fraction of heme rates, which the RDA structure partially but not fully offsets.