The essentials

The richest sources of iron are shellfish, red meat, liver, fortified cereals, beans, lentils and cooked leafy greens. Iron from meat and fish is absorbed best; vitamin C helps with plant iron. Food prevents low iron, but once ferritin and hemoglobin are clearly low, most people also need iron treatment and a search for the cause. Blood tests show whether it is working.

Which foods are highest in iron?

Heme iron (meat, poultry, seafood) is absorbed more easily than non-heme iron (plants and foods with added iron)[2]. The table uses US portions from the federal Dietary Guidelines list[2]. On a Nutrition Facts label, the Daily Value for iron is 18 mg, and 20% DV or more per serving counts as high[3].

Iron in common foods, per standard portion (source: USDA and HHS, 2024)
FoodPortionIron (mg)Type
Fortified ready-to-eat cereal (whole-grain kernels)1/2 cup16.2Non-heme (added)
Oysters3 oysters6.9Heme
Spinach, cooked1 cup6.4Non-heme
Soybeans, cooked1/2 cup4.4Non-heme
Lentils or white beans, cooked1/2 cup3.3Non-heme
Beef or canned sardines3 ounces2.5Heme
Organ meats (various)3 ounces1.8 to 19Heme

Two points most lists leave out. First, the milligrams on a label are not what reaches your blood: from a mixed diet, about 14 to 18% of iron is absorbed, and from a vegetarian diet about 5 to 12%, in people with empty iron stores[4]. Second, your own iron status changes absorption more than the menu does: the lower your stores, the more you absorb[4].

How much iron do you need each day?

US recommended amounts (RDA) are[1]:

  • Men 19 and older, and women 51 and older: 8 mg a day.
  • Women 19 to 50: 18 mg a day, because of menstrual losses.
  • Pregnancy: 27 mg a day. Breastfeeding (19 to 50): 9 mg a day.
  • Children 1 to 3 years: 7 mg; teenage girls: 15 mg[1].

These amounts keep healthy people from running low; they are not a treatment for proven deficiency[5].

What are the signs that you need more iron?

Mild or moderate iron-deficiency anemia may cause no symptoms at all[6]. When symptoms appear, they include tiredness, shortness of breath, dizziness or lightheadedness, cold hands and feet, and pale skin[6]. Craving ice, hair loss and restless legs are also linked to low iron[5].

Low iron does not always mean anemia. Iron deficiency without anemia (normal hemoglobin, low ferritin) is nearly twice as common as iron deficiency with anemia[5], and it can still cause problems[11]. Our page on iron deficiency signs and causes explains both stages.

When should you see a doctor?

When to see a doctor

  • Emergency: call 911 for chest pain, fainting, severe shortness of breath, vomiting blood, or large amounts of black, tarry or bloody stool. These can signal serious bleeding or severe anemia[6][7].
  • Within 24 to 48 hours if you notice black stool or blood in your stool without other warning signs, or if tiredness and breathlessness are getting worse quickly[7].
  • At your next appointment if you have ongoing tiredness, heavy periods, you eat little meat, you donate blood often, or a lab report shows low ferritin or hemoglobin. Do not start iron pills on your own before a blood test[7].

Why does iron run low, and who needs more?

Low iron comes from too little iron eaten, too little absorbed, or blood loss. Diet is only one cause, so food alone does not always fix it[6][11].

  • Common Heavy menstrual periods, pregnancy and childbirth[6][1].
  • Common A diet with few iron-rich foods, including strict vegetarian or vegan diets without planning[5][7]. In a meta-analysis of 24 studies, adult vegetarians had ferritin levels about 30 µg/L lower than non-vegetarians[8].
  • Common Frequent blood donation (see the FAQ)[5].
  • Possible Bleeding in the stomach or gut, for example from ulcers or regular use of aspirin, ibuprofen or naproxen[6].
  • Possible Poor absorption: celiac disease, Crohn's disease, ulcerative colitis, Helicobacter pylori infection, or stomach and weight-loss surgery[6].
  • Possible Endurance sports, and toddlers who drink more than 16 to 24 ounces of cow's milk a day[6][5].
  • Rare Inherited conditions that block iron absorption[6], or cancer of the digestive tract[7].

Which blood tests show whether iron-rich foods are working?

A doctor checks a complete blood count with hemoglobin, and an iron panel with ferritin, serum iron, TIBC and transferrin saturation[5][6]. Ferritin reflects your iron stores; untreated iron deficiency later progresses to anemia, a low hemoglobin[5][9]. Here is a fictitious report.

Fictitious example of a lab report (United States format)
TestResultReference rangeFlag
Hemoglobin11.1 g/dL12.0-15.5 g/dLL
MCV76 fL80-100 fLL
Ferritin8 ng/mL15-150 ng/mLL
Transferrin saturation9 %20-50 %L
  1. Hemoglobin: the oxygen-carrying protein in red blood cells. "L" means it is below the lab's range: this is anemia[5].
  2. MCV: the average size of red blood cells. Small cells fit iron deficiency[5]; see MCV results.
  3. Ferritin: the stored iron. A very low value confirms that stores are empty[5]. The 2026 American Society of Hematology guideline sets ferritin thresholds for each population, even when hemoglobin is normal[9].
  4. Transferrin saturation: how full the iron "trucks" in the blood are; low here[5]. See transferrin saturation.

Changing your diet to raise iron? BloodSense explains your full report line by line, so you can follow ferritin and hemoglobin from one test to the next.

Explain my iron results

Ranges are illustrative; your lab's ranges prevail. Inflammation blocks iron absorption and can make ferritin look normal despite low iron[11][9], which is why a CRP test is sometimes added. If red cells are large rather than small, think of vitamin B12 or folate instead of iron.

How long does it take to raise ferritin and hemoglobin?

Food alone has no reliable timeline: absorption depends on your stores, meals and any blood loss[4]. With iron treatment, anemia often improves within 6 weeks, but refilling stores takes about 6 more months[7]; the NHLBI cites 3 to 6 months to restore iron levels[6].

Your doctor usually repeats the blood count and ferritin to check the response. Ask when your next test should be.

Is food enough, or do you need iron treatment?

Iron deficiency is treated with more dietary iron, iron tablets or intravenous iron, depending on the cause and severity[5]. Oral iron is the first-line treatment in most cases[11], and a multivitamin usually contains too little[5]. Practical points, without doses[5]:

  • Iron tablets are taken no more than once a day; some people tolerate them better every other day.
  • Tea and coffee are best avoided for an hour before and after a tablet, and dairy or calcium-rich foods for two hours.
  • If you have side effects such as constipation or an upset stomach, tell your doctor rather than stopping[6].
  • Intravenous iron restores levels in one or a few sessions, mostly for serious deficiency or long-term conditions[6].

Whatever the treatment, the cause must be found. Celiac disease screening is often considered, and gut examination is warranted in men and postmenopausal women with iron-deficiency anemia[11]. More on causes and treatment is on our anemia symptoms and treatments page.

How can you absorb more iron from your meals?

  • Add a little meat, fish or poultry to beans or leafy greens: this can increase absorption of plant iron up to three times[1].
  • Pair plant iron with vitamin C foods such as citrus, strawberries, tomatoes or potatoes[1].
  • Drink black tea and coffee between meals rather than with them[1][5].
  • Choose fortified breakfast cereals or breads; check the %DV on the label[2][3].
  • Cook in a cast-iron skillet[1].

Phytate, polyphenols and calcium reduce absorption in a single meal, but much less across a varied diet[4]: no need to cut them out.

Who should not load up on iron?

People with hemochromatosis, an inherited condition in which the body absorbs too much iron, are usually told not to take iron pills or vitamins with iron, not to use iron cookware, to limit iron-fortified cereals and to avoid alcohol[10]. A high ferritin calls for a doctor's visit, not just a diet change. Keep iron tablets out of children's reach: they can cause poisoning[1].

Questions to ask your doctor

  1. Is my low iron due to diet, blood loss or poor absorption?
  2. Is food enough, or do I need iron tablets or an infusion?
  3. When should I repeat my ferritin and hemoglobin?
  4. Could inflammation be affecting my ferritin result?
  5. Do I need tests for celiac disease or a gut examination?

Frequently asked questions

Is spinach really a good source of iron?

Cooked spinach is high in iron per cup[2], but it is non-heme iron, which is less well absorbed than iron from meat or fish[2]. Eat it with a vitamin C food or a little meat to help absorption[1].

Can I raise my iron in 7 days?

No. Diet changes and even iron treatment take weeks for hemoglobin and months for ferritin[6][7]. A quick rise is only possible with a transfusion or intravenous iron, which a doctor decides on[6].

Can vegetarians and vegans get enough iron?

Yes, with planning: legumes, tofu, fortified cereals and leafy greens, with vitamin C[6][1]. Their stores tend to be lower, so a ferritin check makes sense if symptoms appear[8].

Does donating blood lower my iron?

Yes. Each donation removes 220 to 250 mg of iron, and refilling stores can take 24 to 30 weeks. Donation centers check hemoglobin but not ferritin, so stores can be low even if you pass the screen[5].

References

  1. MedlinePlus Medical Encyclopedia. Iron in diet. US National Library of Medicine. medlineplus.gov (accessed October 31, 2026)
  2. US Department of Agriculture and US Department of Health and Human Services. Food Sources of Iron: Standard Portions. Dietary Guidelines for Americans; August 2024. dietaryguidelines.gov (accessed October 31, 2026)
  3. US Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels. fda.gov (accessed October 31, 2026)
  4. Hurrell R, Egli I. Iron bioavailability and dietary reference values. Am J Clin Nutr. 2010;91(5):1461S-1467S. doi:10.3945/ajcn.2010.28674F (accessed October 31, 2026)
  5. American Society of Hematology. Iron-Deficiency Anemia (patient information). hematology.org (accessed October 31, 2026)
  6. National Heart, Lung, and Blood Institute. Iron-Deficiency Anemia. National Institutes of Health. nhlbi.nih.gov (accessed October 31, 2026)
  7. MedlinePlus Medical Encyclopedia. Iron deficiency anemia. US National Library of Medicine. medlineplus.gov (accessed October 31, 2026)
  8. Haider LM, Schwingshackl L, Hoffmann G, Ekmekcioglu C. The effect of vegetarian diets on iron status in adults: a systematic review and meta-analysis. Crit Rev Food Sci Nutr. 2018;58(8):1359-1374. doi:10.1080/10408398.2016.1259210 (accessed October 31, 2026)
  9. Powers JM, Lim MY, Achebe MO, et al. American Society of Hematology 2026 guidelines for diagnosis of iron deficiency. Blood Adv. 2026;10(21):7353-7374. doi:10.1182/bloodadvances.2025015950 (accessed October 31, 2026)
  10. MedlinePlus Medical Encyclopedia. Hemochromatosis. US National Library of Medicine. medlineplus.gov (accessed October 31, 2026)
  11. Pasricha SR, Tye-Din J, Muckenthaler MU, Swinkels DW. Iron deficiency. Lancet. 2021;397(10270):233-248. doi:10.1016/S0140-6736(20)32594-0 (accessed October 31, 2026)
  12. MedlinePlus. Ferritin Blood Test. US National Library of Medicine. medlineplus.gov (accessed October 31, 2026)

This page is general information. It does not replace the advice of a doctor or dietitian, who interprets your results with your symptoms, history and examination.