Anemia: Symptoms, Causes, Tests & 5 Natural Treatments

Anemia means your blood is short on healthy red blood cells or on hemoglobin, the iron-rich protein inside them that carries oxygen, so every tissue in your body gets less oxygen than it needs and you feel tired, weak, pale and short of breath.19 It's your body telling you something is draining or starving your blood, usually low iron from heavy periods, poor absorption in the gut or too little iron-rich food, and my approach is to find that root cause, rebuild your blood with food first, and recheck your labs to make sure it's working.210113

Low iron usually comes on in stages. Your iron stores run down first, and your hemoglobin falls only later, once there isn't enough iron left to make new red cells, which means you can feel the drain before a basic blood count flags anything.28 As I put it on my show, "You can have iron stores so low that you're exhausted and still pass a standard anemia test on blood work."6 That's why this guide walks you through the full picture: the symptoms to watch for, the root causes and types, the tests that find what's behind yours, and the five natural treatments that rebuild your blood, from liver and vitamin C pairing to healing your gut.

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What is anemia?

Think of your red blood cells as a fleet of delivery trucks. Each one is loaded with hemoglobin, and iron is the part of hemoglobin that picks up oxygen in your lungs and drops it off in your muscles, brain and organs.9 Most of the 3 to 4 grams of iron in an adult body sits in that hemoglobin, and much of the rest is held in storage as ferritin in your liver, spleen and bone marrow, ready for when your body needs to make new cells.9 When the trucks run short, or run half-empty, every tissue feels it.

Anemia is one of the most widespread health problems on earth. In 2021, about 1.92 billion people, 24.3% of the world's population, were living with it, and dietary iron deficiency was the leading cause of the disability it brought.12 Low iron without anemia is even more common. In national data from 2017 to 2020, about 14% of U.S. adults had low iron stores, and in high-income countries about 38% of women of childbearing age who aren't pregnant have iron deficiency without anemia, while about 13% have iron-deficiency anemia.132

Being anemic means your hemoglobin or red cell count has dropped below the normal range for someone of your age and sex. On a standard lab report, normal hemoglobin runs about 12 to 15 g/dL for adult women and 14 to 17 g/dL for adult men, and those ranges shift with altitude and a few other factors.14

Anemia symptoms: the signs your blood is running low

• Tiredness and weakness that a good night's sleep doesn't fix

• Pale skin, pale lips and nails, and a pale tongue

• Shortness of breath, even on a flight of stairs

• A fast or irregular heartbeat

• Dizziness or headaches

• Cold hands and feet

• Restless legs that keep you up at night

• Cravings for ice, or for things that aren't food

• Brittle nails and thinning hair

Tiredness is the symptom people know best, and it makes sense once you picture those delivery trucks: with less oxygen arriving, every cell has less to make energy with.14 Your heart and lungs try to make up the difference, which is why you may find yourself breathing hard on the stairs or feeling your heart race.4 In my clinical practice, the patients I've had with chronic fatigue syndrome have often had low iron or ferritin on their blood work.4

Restless legs and cravings for ice are two of the most telling signs. Restless legs, that crawling urge to move your legs at night, turned up in 23.9% of 251 people newly referred to a hematology practice for iron-deficiency anemia, about nine times the rate in the general population, and those people slept worse and had less energy during the day.16 Cravings for ice are another clue. In a study of 262 adults being treated for low iron, 45% reported pica, the urge to eat things that aren't food, and 87.3% of them craved ice.17

Low iron shows in your hair and nails too. In a review of studies covering 10,029 people, women with hair loss had lower ferritin than women without it.15 The other common signs, cold hands and feet, brittle nails and headaches, all trace back to tissues getting less oxygen.4

In traditional Chinese medicine, the tongue is one of the first places to look. When you stick out your tongue, it should be a bright, vibrant pink, and a pale tongue is the classic sign of what the tradition calls blood deficiency.6 Modern research backs the tongue as a useful clue. In a hospital study of 390 patients in India, examiners who didn't know the blood results found that a pale tongue picked out anemia better than pale inner eyelids, palms or nail beds, and it was most reliable once hemoglobin had fallen below 7 g/dL.18 So use a pale tongue as your reason to get tested, and let the blood test give you the number. Some people with low iron have no symptoms at all, which is one more reason the right tests matter.2

What causes anemia? How your body builds blood, and where it breaks down

Your bone marrow makes new red blood cells every day, and it can only build them with a steady supply of iron, vitamin B12 and folate, along with helpers such as copper.9214 Building blood works a lot like a supply chain. The raw materials have to come in through your food, get through the lining of your gut, reach the marrow, and not drain away faster than you can replace them, and anemia shows up when any link in that chain breaks.

Follow the chain below, with the step that repairs each link.

Blood loss: heavy periods and hidden bleeding

For women, heavy periods are among the biggest drivers of low iron and anemia, from the first period to menopause, and they're so common that girls, women and even their healthcare providers tend to treat them as normal.10 Bleeding you can't see is the other big cause. Regular use of anti-inflammatory pain relievers called NSAIDs, inflammatory bowel disease and bleeding in the stomach or bowel can all slowly drain your iron, and so can frequent blood donation.219 That's why, in a man or a woman past menopause, finding the source of hidden bleeding is the first step to rebuilding.8

Poor absorption: when your gut can't take in iron and B12

You can eat plenty of iron and still run low if your gut can't absorb it. Celiac disease is one of the most important causes to rule out: in a review of 18 studies of 2,998 people with iron-deficiency anemia, 3.2% had celiac disease confirmed by biopsy, about 1 in 31.11 The stomach bacterium H. pylori matters too. Across 14 observational studies, people infected with it had 1.72 times the odds of iron-deficiency anemia.23 In the small intestine, SIBO, small intestinal bacterial overgrowth, competes with you for B12 first, and iron absorption suffers as well.24 Weight-loss surgery that bypasses part of the gut also cuts iron absorption.2

Some everyday medications work against you here. In a California health-system study comparing 25,956 people with B12 deficiency with 184,199 people without it, two or more years' supply of acid-blocking proton pump inhibitors went with 65% higher odds of deficiency.25 In a diabetes prevention trial that randomly assigned 2,155 adults to metformin or placebo, low B12 turned up more often on metformin when 1,715 of them were tested at 5 years (4.3% against 2.3%).32

Too little iron, B12 or folate coming in

How much iron you absorb depends a great deal on its source. In figures calculated for people with no iron stores, your body absorbs an estimated 14% to 18% of the iron in a mixed diet that includes meat, against 5% to 12% from a vegetarian diet.22 Plants also carry no B12, and in a review of 40 studies, B12 deficiency was common among vegetarians and highest among vegans who didn't take B12.33 If you eat a vegan diet, a B complex with B12 and regular iron checks matter more for you than for almost anyone.333

Pregnancy, birth and the years after

Pregnancy asks your body to build extra blood and pass iron to the baby, and in high-income countries, iron deficiency affects up to 84% of women in the third trimester.2 Breastfeeding and the return of your period keep drawing on those stores after the baby arrives.6 As I said on my show, "I see this with a lot of moms, especially young moms. They never built their blood back after giving birth."6 Many traditional cultures kept new mothers on a special diet for the first 90 days after birth, with soups, broths and other warming foods and plenty of rest, to build their blood back, and that's the wisdom natural treatment 4 builds on.6

Inflammation and chronic illness

Chronic kidney disease, long-running infections, cancer and autoimmune disease can all slow red cell production.19 Inflammation also triggers hepcidin, the hormone that keeps iron out of your blood, so your body holds its iron back even when there's some in storage.8 That's why calming chronic inflammation is part of rebuilding your blood, alongside the iron itself.

How traditional Chinese medicine sees anemia

Traditional Chinese medicine reads anemia as blood deficiency, a pattern in which the blood isn't nourished enough to carry iron, oxygen and nutrients out to the rest of your body.6 Its signs read like the symptom list above: exhaustion, a little dizziness when you stand up, pale lips and nails, poor sleep, thinning hair and, above all, a pale tongue.6 In TCM, blood is created by the Spleen and moved through the body by the Liver, and the Spleen in this tradition really means your digestion, so building blood starts with eating and digesting well, with rest and joy alongside warm, cooked food.3435

Types of anemia

Anemia is sorted by what's behind it and by the size of your red cells, and knowing your type tells you what will help. A complete blood count measures cell size as the MCV (mean corpuscular volume): small cells point toward low iron, while large cells point toward low B12 or folate.143021

Iron-deficiency anemia

This is the type most people mean when they say anemia. Your marrow runs short of iron and makes small, pale red cells, after your stores have been drained by blood loss, poor absorption, low intake or the demands of pregnancy.230

Vitamin B12 deficiency and pernicious anemia

Without enough B12, your marrow can't finish building red cells, so it turns out fewer, oversized ones, and a long-running deficiency can also affect your nerves.21 Pernicious anemia is an autoimmune form in which your body can no longer absorb B12 from food, and a B12 form that bypasses the gut, under the tongue or by injection, is one way around it.213 It's also the type liver made medical history with, in the 1926 study in natural treatment 1.36 Our guide to vitamin B12 deficiency covers the other signs.

Folate-deficiency anemia

Folate works hand in hand with B12 to build red cells, and a shortfall also produces large cells.21 Liver, beans and leafy greens are all good sources, so it's most likely when those are scarce on your plate.373839 See our guide to folate deficiency for the full picture.

Anemia of chronic disease

Here, inflammation from a long-term illness such as kidney disease, an autoimmune condition or a chronic infection keeps iron locked away through hepcidin and slows red cell production, even when your iron stores aren't empty.819

Inherited and bone marrow types

Sickle cell disease is a group of inherited disorders that affect hemoglobin, and thalassemia is an inherited blood disorder passed from parents to children through genes.4041 In aplastic anemia, the bone marrow can't make enough new blood cells, and in hemolytic anemia, red cells are destroyed faster than they can be replaced.4220

Which tests diagnose anemia?

My rule is test, don't guess.3 A complete blood count is where testing starts: it measures your red cells, hemoglobin and hematocrit, the share of your blood made up of red cells, along with the MCV, the average size of your red cells.14 It tells you whether you're anemic but not why, and that's where the next tests come in.

Ferritin is the real iron gauge, because it reflects the iron you have in storage.69 The optimal range is 50 to 150 ng/mL for women and 75 to 150 ng/mL for men.3 Standard cutoffs sit well below that: iron deficiency is usually diagnosed at a ferritin under 30 ng/mL, the World Health Organization's cutoff for healthy adults is under 15, and in U.S. national data, red cell production in women who weren't pregnant began to suffer at a ferritin of about 25.24344 Ask for the full iron panel with it: serum iron, total iron-binding capacity and transferrin saturation, since a saturation under 20% also points to low iron, and inflammation can push ferritin up and hide a shortage.23

For B12, a standard blood level isn't the whole story. MMA (methylmalonic acid) builds up in your tissues when your cells run short of B12, so it can catch a deficiency that a normal-looking B12 result misses. My bloodwork guide puts it plainly: "If your B12 looks normal but your energy is wrecked, run MMA. You'll often find the answer there."3 Check folate at the same time.

If iron is low and the reason isn't obvious, the cause gets tested too. Screening for celiac disease is worth considering in anyone with iron deficiency, and a test for H. pylori belongs on the list when absorption may be the problem.83

The labs to ask for when you suspect anemia

Can you have low iron without anemia?

Yes, and it can still wear you out. In a Swiss trial, 144 women aged 18 to 55 with unexplained fatigue and normal hemoglobin took 80 mg of iron a day or a look-alike placebo for 4 weeks, and neither the women nor the researchers knew who got what. Among the 136 who finished, fatigue fell 29% on iron against 13% on placebo, and only the women with a ferritin of 50 or lower improved.45 A second placebo-controlled trial, in 198 menstruating women with fatigue, a ferritin under 50 and no anemia, found the same pattern over 12 weeks, with fatigue scores falling 47.7% on 80 mg of iron a day against 28.8% on placebo.46 Drug companies sponsored both trials, and the second company also designed its study.4546 A 2018 review of 18 trials in 1,170 adults with low iron but no anemia found that iron eased self-reported fatigue when 4 of those trials (714 people) were pooled.47 If tiredness is your main complaint, our guide to being always tired covers the other causes to check.

5 natural treatments for anemia

The rule I gave in my 2015 anemia video still holds: "Treat the root cause, not the symptom."35 An iron pill can't do its job if heavy bleeding keeps draining your stores or your gut can't absorb what you take, so these five treatments start with food and the gut, and they save targeted supplements for what your labs show.35

Anemia diet: the best foods to build your blood

Food is where rebuilding your blood starts, and liver and red meat do the heaviest lifting because their heme iron absorbs best.4 Plant foods still add real iron, and some of them carry more per serving than steak, but your body takes in less of it, so pair them with vitamin C and cook your greens.224 The table below shows how some of the best iron-rich foods compare; meat and liver carry both heme and nonheme iron, while plants carry only nonheme.9

Iron, B12 and folate in a typical serving

The foods I recommend for anemia start with liver and grass-fed beef, bison and lamb, then egg yolks, leafy greens, beets, blackstrap molasses and kidney beans, with vitamin C foods such as broccoli and red bell peppers and fruits such as cherries, figs, raspberries and prunes.34 Sardines belong on the list too.3

The foods that work against you are mostly about timing. Sugar, soda and processed food crowd out the foods that build blood, and bran, chocolate, coffee, black tea and dairy all get in the way of iron when they share a meal with it.34292728 Save your tea, coffee and dairy for between meals, choose sprouted or fermented grains, and let your iron-rich meals stand on their own.4

Recipes to build your blood

These meals put the treatments above on your plate. The first is the slow-cooker meal I described in my 2015 anemia video, written out as a home recipe.35

More ideas from the treatments above:

• A bison burger with a side of sautéed spinach. It's another meal from my 2015 video, and a squeeze of lemon over the spinach adds vitamin C.35
• Slow cooker bison chili. Bison, black beans and kidney beans bring the iron, and the bell pepper and tomatoes bring vitamin C.
• Butternut squash soup. A warm, easy-to-digest bowl that counts toward your daily squash.
• Sautéed kale. Cooked greens with garlic and onion; add red bell pepper for vitamin C.
• Roasted beet salad. Beets with orange and a little goat cheese, best eaten between your iron-rich meals because of the cheese.

When to see a doctor about anemia

My Acid Reflux & GERD Protocol puts anemia on its red-flag list beside trouble swallowing, weight loss, vomiting blood and black stools, the signs that call for a doctor and a scope before any protocol.7

Test before you take iron. Your body has no way to get rid of extra iron, and too much damages cells, so take iron only after a ferritin test and a full iron panel.223 If you have hemochromatosis or a high ferritin, skip iron supplements; high ferritin is treated by removing blood, under a doctor's care.3

Children. Accidental overdose of iron products is a leading cause of fatal poisoning in children under 6, so keep every iron supplement out of their reach.66

Pregnancy and breastfeeding. Confirm the dose of any iron, B12 or folate supplement with your OB. Skip dong quai while you're pregnant or breastfeeding, since it can raise the risk of miscarriage.67 Ask your OB about liver too, because 3 ounces of beef liver carries about 6,579 µg of vitamin A.50

Medications. Iron supplements can interact with levothyroxine, a thyroid medication, and with levodopa, and acid blockers can lower iron absorption, so ask the doctor who prescribes them how to time your iron.9 Don't stop an acid blocker or metformin on your own; ask about checking B12 and ferritin instead.732 If you take warfarin, check with your prescriber before taking dong quai: in one documented case, a woman's INR, the standard clotting test for warfarin, roughly doubled after 4 weeks on the herb.6867

Side effects. If iron upsets your stomach or bowels, switch to a gentler form such as bisglycinate and take it every other day.616248

Inherited and marrow types. Sickle cell disease, thalassemia, aplastic anemia and hemolytic anemia need a specialist's care, and iron supplements aren't the answer for them unless a test shows you're also low on iron.3

The bottom line

Anemia: frequently asked questions

References

1. National Heart, Lung, and Blood Institute. Anemia: What Is Anemia? (definition; symptoms: tiredness or weakness, shortness of breath, dizziness, headaches, irregular heartbeat; anemia may signal bleeding, infection, kidney disease, cancer or autoimmune disease). Accessed 2026-11-04.
2. Auerbach M, DeLoughery TG, Tirnauer JS. Iron Deficiency in Adults: A Review. JAMA. 2025;333(20):1813-1823. doi:10.1001/jama.2025.0452. PMID:40159291
3. Axe J, Cole W. The 25 Root-Cause Bloodwork Markers That Matter Most. DrAxe.com protocol. 2026. Cover, p. 1 (Test. Don't guess.); marker 12, MMA (B12 status), p. 16 (root causes; actions: methylcobalamin 1,000 to 5,000 mcg a day, sublingual or injection bypasses the gut, pair with methylfolate 400 to 800 mcg; clinical pearl quoted on this page); marker 13, ferritin and the full iron panel, p. 17 (optimal range women 50 to 150 ng/mL, men 75 to 150; root causes of low ferritin: heavy menses, gut inflammation, low stomach acid, H. pylori, vegetarian and vegan diets; actions: red meat, liver and sardines with vitamin C, test the full panel, address H. pylori or SIBO, therapeutic phlebotomy for high ferritin).
4. Axe J. 10 Signs You Have an Iron Deficiency (How to Boost Iron Naturally). The Dr. Josh Axe Show. 2024. Lines at 7:07 (low iron or ferritin in his patients with chronic fatigue syndrome), 11:16 (his wife's liver and organ capsules after the births of both their children), 13:05 to 15:42 (signs of low iron: fatigue, pale skin and tongue, shortness of breath, dizziness, cold hands and feet, brittle nails and hair, headaches, palpitations, restless legs, unusual cravings), 17:28 to 18:12 (heme iron; vitamin C the most significant enhancer of nonheme iron absorption), 20:05 to 21:42 (calcium and iron; meat and dairy kept apart in Chinese medicine and Jewish dietary law), 21:49 to 23:21 (sprouting and fermenting grains), 23:21 to 24:13 (tea and coffee between meals), 24:21 to 25:38 (organ meats, and especially liver, the number one food for building back iron), 25:41 to 26:35 (cook spinach and kale, or have them raw in a spinach and strawberry salad, and pair them with vitamin C foods), 26:37 to 27:40 (nettle and dandelion teas), 29:27 to 30:18 (dong quai, one of the top 10 herbs in Chinese medicine).
5. Axe J. You Were Lied To About Fat — Your Cells Are Paying the Price. The Dr. Josh Axe Show. October 5, 2026. Lines at 15:59 to 16:09 (3 ounces of beef liver once a week) and 16:09 to 16:21 (ground grass-fed beef blended with liver and heart, so you don't taste the liver).
6. Axe J. The Real Reason You Wake Up Tired Every Morning. The Dr. Josh Axe Show, Episode 377. 2026. Lines at 8:39 (blood deficiency in Chinese medicine), 9:07 (iron stores low enough to exhaust you while you pass a standard anemia test; ferritin the real iron gauge), 10:01 (iron plus vitamin C every other day), 10:14 (how he doses iron in clinic), 10:53 ("The rule is wrong"), 11:18 to 12:07 (signs of blood deficiency; a pale tongue), 12:21 (dong quai, beets, lean red meat, steamed greens, warming soups), 12:48 to 13:26 (young mothers, at 13:00; the 90-day postpartum diets of traditional cultures).
7. Axe J. Acid Reflux & GERD Protocol: The 30-Day Healing Protocol. DrAxe.com protocol. 2026. Page 11, what long-term acid suppression depletes (ask for B12, magnesium and ferritin after a year on an acid blocker; tapers only with the prescriber); page 14, red flags (trouble swallowing, weight loss, vomiting blood, black stools or anemia mean a doctor and a scope before any protocol).
8. 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. PMID:33285139
9. National Institutes of Health, Office of Dietary Supplements. Iron: Fact Sheet for Health Professionals (iron in hemoglobin; 3 to 4 grams of iron in adults, stored as ferritin in the liver, spleen and bone marrow; hepcidin; heme and nonheme iron; take calcium and iron supplements at different times; interactions with levodopa and levothyroxine; proton pump inhibitors can reduce iron absorption; upper limit 45 mg a day for adults). Accessed 2026-11-04.
10. Munro MG, Mast AE, Powers JM, Kouides PA, O'Brien SH, Richards T, et al. The relationship between heavy menstrual bleeding, iron deficiency, and iron deficiency anemia. Am J Obstet Gynecol. 2023;229(1):1-9. doi:10.1016/j.ajog.2023.01.017. PMID:36706856
11. Mahadev S, Laszkowska M, Sundström J, Björkholm M, Lebwohl B, Green PHR, et al. Prevalence of Celiac Disease in Patients With Iron Deficiency Anemia-A Systematic Review With Meta-analysis. Gastroenterology. 2018;155(2):374-382.e1. doi:10.1053/j.gastro.2018.04.016. PMID:29689265
12. GBD 2021 Anaemia Collaborators. Prevalence, years lived with disability, and trends in anaemia burden by severity and cause, 1990-2021: findings from the Global Burden of Disease Study 2021. Lancet Haematol. 2023;10(9):e713-e734. doi:10.1016/S2352-3026(23)00160-6. PMID:37536353
13. Tawfik YMK, Billingsley H, Bhatt AS, Aboelsaad I, Al-Khezi OS, Lutsey PL, et al. Absolute and Functional Iron Deficiency in the US, 2017-2020. JAMA Netw Open. 2024;7(9):e2433126. doi:10.1001/jamanetworkopen.2024.33126. PMID:39316402
14. National Heart, Lung, and Blood Institute. Anemia: Diagnosis (complete blood count with hemoglobin, hematocrit and mean corpuscular volume; normal hemoglobin for adult men 14 to 17 g/dL and adult women 12 to 15 g/dL, varying with altitude and other factors). Accessed 2026-11-04.
15. Treister-Goltzman Y, Yarza S, Peleg R. Iron Deficiency and Nonscarring Alopecia in Women: Systematic Review and Meta-Analysis. Skin Appendage Disord. 2022;8(2):83-92. doi:10.1159/000519952. PMID:35415182
16. Allen RP, Auerbach S, Bahrain H, Auerbach M, Earley CJ. The prevalence and impact of restless legs syndrome on patients with iron deficiency anemia. Am J Hematol. 2013;88(4):261-4. doi:10.1002/ajh.23397. PMID:23494945
17. Barton JC, Barton JC, Bertoli LF. Pica associated with iron deficiency or depletion: clinical and laboratory correlates in 262 non-pregnant adult outpatients. BMC Blood Disord. 2010;10:9. doi:10.1186/1471-2326-10-9. PMID:21176208
18. Kalantri A, Karambelkar M, Joshi R, Kalantri S, Jajoo U. Accuracy and reliability of pallor for detecting anaemia: a hospital-based diagnostic accuracy study. PLoS One. 2010;5(1):e8545. doi:10.1371/journal.pone.0008545. PMID:20049324
19. National Heart, Lung, and Blood Institute. Anemia: Causes and Risk Factors (blood loss from heavy periods, stomach or bowel bleeding, surgery, injury or frequent blood donation; chronic kidney disease, infection, cancer and autoimmune disease; low iron, vitamin B12 or folic acid; inherited types). Accessed 2026-11-04.
20. National Heart, Lung, and Blood Institute. Hemolytic Anemia (red blood cells destroyed faster than they can be replaced). Accessed 2026-11-04.
21. Stabler SP. Clinical practice. Vitamin B12 deficiency. N Engl J Med. 2013;368(2):149-60. doi:10.1056/NEJMcp1113996. PMID:23301732
22. 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. PMID:20200263
23. Hudak L, Jaraisy A, Haj S, Muhsen K. An updated systematic review and meta-analysis on the association between Helicobacter pylori infection and iron deficiency anemia. Helicobacter. 2017;22(1). doi:10.1111/hel.12330. PMID:27411077
24. Axe J. SIBO Protocol: The 60-Day Healing Protocol. DrAxe.com protocol. 2026. Page 13, what SIBO takes from you (B12 first, with iron absorption also affected).
25. Lam JR, Schneider JL, Zhao W, Corley DA. Proton pump inhibitor and histamine 2 receptor antagonist use and vitamin B12 deficiency. JAMA. 2013;310(22):2435-42. doi:10.1001/jama.2013.280490. PMID:24327038
26. Morck TA, Lynch SR, Cook JD. Inhibition of food iron absorption by coffee. Am J Clin Nutr. 1983;37(3):416-20. doi:10.1093/ajcn/37.3.416. PMID:6402915
27. Hurrell RF, Reddy M, Cook JD. Inhibition of non-haem iron absorption in man by polyphenolic-containing beverages. Br J Nutr. 1999;81(4):289-95. PMID:10999016
28. Hallberg L, Brune M, Erlandsson M, Sandberg AS, Rossander-Hultén L. Calcium: effect of different amounts on nonheme- and heme-iron absorption in humans. Am J Clin Nutr. 1991;53(1):112-9. doi:10.1093/ajcn/53.1.112. PMID:1984335
29. Hallberg L, Brune M, Rossander L. Iron absorption in man: ascorbic acid and dose-dependent inhibition by phytate. Am J Clin Nutr. 1989;49(1):140-4. doi:10.1093/ajcn/49.1.140. PMID:2911999
30. DeLoughery TG. Microcytic anemia. N Engl J Med. 2014;371(14):1324-31. doi:10.1056/NEJMra1215361. PMID:25271605
31. Stoffel NU, Zeder C, Brittenham GM, Moretti D, Zimmermann MB. Iron absorption from supplements is greater with alternate day than with consecutive day dosing in iron-deficient anemic women. Haematologica. 2020;105(5):1232-1239. doi:10.3324/haematol.2019.220830. PMID:31413088
32. Aroda VR, Edelstein SL, Goldberg RB, Knowler WC, Marcovina SM, Orchard TJ, et al. Long-term Metformin Use and Vitamin B12 Deficiency in the Diabetes Prevention Program Outcomes Study. J Clin Endocrinol Metab. 2016;101(4):1754-61. doi:10.1210/jc.2015-3754. PMID:26900641
33. Pawlak R, Lester SE, Babatunde T. The prevalence of cobalamin deficiency among vegetarians assessed by serum vitamin B12: a review of literature. Eur J Clin Nutr. 2014;68(5):541-8. doi:10.1038/ejcn.2014.46. PMID:24667752
34. Axe J. Ancient Remedies: Secrets to Healing with Herbs, Essential Oils, CBD, and the Most Powerful Natural Medicine in History. New York: Little, Brown Spark; 2021. ISBN 9780316496414. Anemia entry (foods that harm and heal; top 5 ancient prescriptions: dong quai 1 g three times daily, a food-based iron 10 to 30 mg daily with 1,000 mg vitamin C, astragalus 500 to 2,000 mg daily, probiotics, desiccated liver 3 g daily) and the traditional Chinese medicine section on blood deficiency (blood is created by the spleen and moved by the liver; blood-building and blood-depleting foods; joy to counteract worry).
35. Axe J. 5 Step Process to Treat Anemia Naturally. Dr. Josh Axe on YouTube. July 7, 2015. Lines at 0:49 to 1:44 (squash, one to two servings a day; leafy greens; bitter foods), 1:59 ("You are what you digest"), 2:49 (treat the root cause), 3:00 (yogurt, goat's milk kefir, sauerkraut), 4:25 to 5:36 (beef and chicken liver; the slow-cooker meal of about a third chicken liver and two-thirds chicken with carrots, celery, onions and sea salt; grass-fed beef, bison and lamb; a bison burger with spinach), 5:39 to 6:03 (worry, anger and unforgiveness; rest and sleep).
36. Minot GR, Murphy WP. Treatment of pernicious anemia by a special diet. 1926. Yale J Biol Med. 2001;74(5):341-53. PMID:11769340
37. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Chicken, liver, all classes, cooked, simmered. FDC ID 171061. SR Legacy (per 100 g: iron 11.6 mg, vitamin B12 16.8 µg, folate 578 µg).
38. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Lentils, mature seeds, cooked, boiled, without salt. FDC ID 172421. SR Legacy (per 100 g: iron 3.33 mg, folate 181 µg; 1 cup = 198 g).
39. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Spinach, cooked, boiled, drained, without salt. FDC ID 168463. SR Legacy (per 100 g: iron 3.57 mg, folate 146 µg; 1 cup = 180 g).
40. National Heart, Lung, and Blood Institute. Sickle Cell Disease (a group of inherited disorders that affect hemoglobin). Accessed 2026-11-04.
41. National Heart, Lung, and Blood Institute. Thalassemia (an inherited blood disorder). Accessed 2026-11-04.
42. National Heart, Lung, and Blood Institute. Aplastic Anemia (the bone marrow cannot make enough new blood cells). Accessed 2026-11-04.
43. World Health Organization. WHO guideline on use of ferritin concentrations to assess iron status in individuals and populations. Geneva: WHO; 2020 (ferritin below 15 ng/mL in healthy adults indicates iron deficiency; below 70 with infection or inflammation).
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50. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Beef, variety meats and by-products, liver, cooked, pan-fried. FDC ID 168627. SR Legacy (per 100 g: iron 6.17 mg, vitamin B12 83.1 µg, folate 260 µg, copper 14.6 mg, vitamin A 7,740 µg RAE; 3 oz = 85 g).
51. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Beef, top sirloin, steak, separable lean only, trimmed to 0" fat, all grades, cooked, broiled. FDC ID 168634. SR Legacy (per 100 g: iron 1.96 mg, vitamin B12 1.71 µg).
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54. Axe J. 10 Biblical Superfoods That Can Add Years to Your Life. The Dr. Josh Axe Show, Episode 393. September 28, 2026. Red-meat studies and grain-fed meat at 21:03 to 21:16.
55. Axe J, Cole W. Heal Your Cells. New York: Avery; 2026. ISBN 9798217181353. Sprouting and fermenting lower phytic acid and free more iron, zinc, calcium and magnesium; dong quai as a traditional Chinese blood tonic.
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58. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Peppers, sweet, red, raw. FDC ID 170108. SR Legacy (per 100 g: vitamin C 128 mg; 1 cup chopped = 149 g).
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65. U.S. Department of Agriculture, Agricultural Research Service. FoodData Central: Seeds, pumpkin and squash seed kernels, dried. FDC ID 170556. SR Legacy (per 100 g: iron 8.82 mg; 1 oz = 28.35 g).
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67. Memorial Sloan Kettering Cancer Center. Dong Quai (About Herbs): avoid it if you're pregnant or breastfeeding; it may increase bleeding risk with blood thinners such as warfarin. Last updated July 29, 2026.
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69. The Holy Bible, King James Version. Leviticus 17:11.

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