Iron Deficiency Anemia

Anemia, which means “without blood”, is a condition when the body doesn’t have enough healthy red blood cells (RBCs) to carry oxygen to all of the tissues. If you think of oxygen as a nutrient, than it is the most important nutrient. We can survive for days without food or water, but can survive for only a few minutes without oxygen.

Iron deficiency anemia is the most common nutrient disorder in the entire world. In America, 5% of women and 2% of men have iron deficiency anemia. (R)

Iron is an important mineral needed to produce hemoglobin and red blood cells, which transports oxygen in the blood to all of the cells and tissues of the body. (R)

Iron is also part of different enzymes involved in cellular respiration and energy generation.

When the body doesn’t have enough iron, it is unable to produce healthy red blood cells, which decreases the ability to transport oxygen around the body. (R)

Iron levels in the body are maintained through dietary intake, iron stores, and iron loss. Tissue oxygenation, red blood cell turnover, and red blood cell loss from bleeding all influence iron demands. (R)

We have the ability to recycle 20 mg of iron from old red blood cells, and use that iron for producing new red blood cells. Every day, 1.0 mg of iron is absorbed from food and 20 mg is recycled from old red blood cells.  If we aren’t consuming enough iron for our needs, then we will continue to use up our iron stores. Once our iron stores are depleted, then there won’t be enough iron to support healthy red blood cell production. (R)

Most of the time, the body will use most or all of the stored iron before iron deficiency anemia actually occurs. For this reason, iron deficiency anemia usually takes months or years to develop, unless abnormal blood loss is occurring and/or a disorder is present that significantly reduces iron in the body. (R)

Enterocytes (small intestinal cells) play a key role in the absorption process. The enterocytes can increase absorption rates based on iron needs, but cannot take up more than 20-40 mg/day.  The more dietary iron we consume, the less will be absorbed. These absorption rates help to regulate and protect our bodies from having too much or too little iron. (R)

Our bodies don’t have any mechanism of getting rid of excess iron. Instead, we lose it through blood loss and sloughing of cells.  If the body needs more iron, it can increase the absorption of iron on its own, but this isn’t always enough to compensate for too much iron loss. (R)

 

Causes of Iron Deficiency Anemia

The 3 main ways in which a person can develop iron deficiency anemia are inadequate dietary iron intake, inability to absorb and use iron, and/or losing too much iron through blood loss. There are many conditions that can contribute to one or all of these.

  • Inadequate dietary intake (R)
  • Decreased iron absorption (R)
  • Increased iron needs (R)
  • Increased iron loss (R)
  • Abnormal bleeding (R)
  • Long-term use of nonsteroidal anti-inflammatory drugs (NSAIDs) (R)
  • Abnormal uterine bleeding (R)
  • Gastrectomy (R)
  • Colon, stomach, or other cancer (R)
  • H. pylori infection (R)
  • Nosebleeds (R)
  • Donating blood (R)
  • Chronic physical exertion (R)
  • Chronic kidney disease (R)
  • Rheumatoid arthritis (R)
  • Inflammatory bowel disease (R)
  • Celiac disease (R)
  • Malaria (R)
  • Hookworms (R)
  • Decreased stomach acid

Nosebleeds and blood donation are two causes of iron deficiency that are often overlooked. (R)

25-35% of people who donate blood develop iron deficiency (I’ve seen a lot of people who donate blood become iron deficient).  One study found that 2/3 of blood donors are unable to restore the iron they lost after 24 weeks (2 years) if they don’t take an iron supplement. (R)

Chronic physical exertion, such as a marathon or training for a marathon, causes a lot of iron to be lost through sweat. (R)

Some genetic disorders that can lead to iron deficiency anemia are iron-refractory iron deficiency anemia, divalent metal transport deficiency anemia, fanconi anemia, and pyruvate kinase deficiency. (R)

Women who are pregnant or menstruating require a high amount of iron. Its estimated that about 1200 mg of iron is required from the time of conception through delivery.  Also, breastfeeding mothers lose iron through breast milk in the form of lactoferrin. (R)

Hookworms are found in the soil of tropical regions. It enters via the mouth or through the skin. It will find its way to the gut and may stay there for several years.  Hookworm eggs can be found in the stool for diagnosis, or a capsule endoscopy can also be used for detection. They feed on blood, which contributes to iron deficiency. If you travel a lot, and have symptoms of iron deficiency, this could be a plausible explanation. (R)

If the gut is unable to absorb iron properly, this will lead to iron deficiency anemia. An oral iron absorption test can see if you have iron malabsorption. (R)

 

Signs and Symptoms

The most common symptom of iron deficiency anemia is fatigue.

Other symptoms include:

  • Poor mental performance (R)
  • Cold intolerance (R)
  • Hard to breathe during exercise (R)
  • Restless leg syndrome (R)
  • Pica (eating strange foods like tons of ice or clay) (R)
  • Pale skin
  • Nail beds
  • Vertigo
  • Syncope
  • Tachycardia headache
  • Dry and rough skin
  • Dry and damaged hair
  • Alopecia
  • Decreased physical performance (R)

Iron deficiency can cause microcytic anemia (small red blood cells). (R)

Iron deficiency anemia can affect cognitive development in children, but can be reversible if treated early enough. (R)

Iron needs are high during rapid growth (i.e. childhood or pregnancy). Children who are iron deficient are more likely to fail in school, have problems with math, comprehension, and have conflictive behavior with parents and teachers. (R)

 

Testing for Iron Status

Note: I pulled the following lab values come from the text book “Krause’s Food and the Nutrition Care Process Edition 13”, because most of the articles and sites I’ve looked at have slightly different variations as to what is considered the normal range for certain lab values. Your test results should come with normal lab value ranges listed on the document.

Ferritin

Serum ferritin is the best test for diagnosing iron deficiency anemia, because it reflects how much iron is stored in the body. Ferritin can hold up to 4500 iron molecules.  Ferritin of ≤ 15 μg/L is defined as iron deficiency. At about 40 μg/L, red blood cell production (erythropoiesis) is negatively affected. This means that before iron deficiency anemia is even diagnosed, the body is already having a hard time. (R)

When testing ferritin, it’s important to understand that it is also an acute phase reactant, which means that when the body is under stress, such as chronic inflammation or infections, serum ferritin will be elevated. (R) Inflammation causes ferritin to rise, which may not accurately reflect how much iron there is in the body. (R)

Normal Ferritin Values

Adult Population

Ferritin

Male

12-300 ng/mL (12-300 mcg/L)

Female

10-150 ng/mL (10-150 mcg/L)

 

Hemoglobin

Hemoglobin is the protein that carries oxygen in red blood cells.  More than half of all of the iron in the body is actually contained in hemoglobin, making it the most abundant iron-containing protein. Hemoglobin values vary depending on age, sex, race, and whether the blood sample was taken from the finger or a vein. (R)

Normal Hemoglobin Values

Adult Population

Hemoglobin - Hb (g/dL)

Male

12-15 g/dL (7.45-9.31 mmol/L)

Female

14-17 g/dL (8.44-10.6 mmol/L)

 

Hematocrit

Hematocrit is a measure of how many red blood cells are in your blood.

Normal Hematocrit Values

Adult Population

Hematocrit (%)

Male

42-52%

Female

35-47%

 

Serum Iron

Not the best test for assessing iron status because it can fluctuate day-to-day. It reflects the most recent iron intake.

Normal Serum Iron Values

Adult Population

Serum Iron

Male

50-160 mcg/dL (8.9-28.7 mmol/L)

Female

40-150 mcg/dL (7.2-26.9 mmol/L)

 

Transferrin

Transferrin is the protein that transports iron in the blood. Transferrin expression also increases when there is less iron.  When there is less iron, there will be an increase in soluble transferrin. (R) Iron is transported via transferrin to bone marrow, where it used for the synthesis of hemoglobin and red blood cells. (R)

Transferrin binds iron from the gut (diet), macrophages (recycled iron), and the liver (stored ferritin iron). (R)

Higher lab values of transferrin could indicate iron deficiency anemia. (R)

Normal Transferrin (Tf or TFN) Values

Adult Population

Transferrin (Tf or TFN)

Male

215-365 mg/dL (2.15-3.65 g/L)

Female

250-380 mf/dL (2.5-3.8 g/L)

 

Transferrin Saturation

Normal Transferrin Saturation

Adult Population

Transferrin Saturation (%)

Male

20-50%

Female

15-50%

 

Total Iron Binding Capacity (TIBC)

This test is similar to that of transferrin, as it reflects transferrin concentration. Total iron binding capacity (TIBC) is measuring the bloods capacity to bind iron with transferrin. TIBC won’t increase until iron stores are depleted.

Normal Total Iron Binding Capacity (TIBC)

Adult Population

Total Iron Binding Capacity (TIBC)

Male

250-400 mcg/dL (45-71 mmol/L)

Female

250-400 mcg/dL (45-71 mmol/L)

 

Mean Corpuscular Volume and Hemoglobin

Iron deficiency anemia is characterized by microcytic (small red blood cells), hypochromic erythrocytes (pale colored red blood cells). The following values are used to determine if red blood cells are microcytic and hypochromic: mean corpuscular volume (average red blood cell volume) <80-100 fL and mean corpuscular hemoglobin <320-360 g/l.  However, up to 40% of people who have iron deficiency anemia will have normal red blood cells. (R)

Red Blood Cell Distribution Width (RDW)

Higher than normal red blood cell distribution width (RDW) may indicate that there is more than one type of anemia present, such as megaloblastic anemia (B12 or folate deficiency) and iron deficiency anemia (microcytic). (R)

Red blood cell distribution width (RDW) can also help distinguish thalassemia (low MCV and normal RDW) from iron deficiency anemia (low MCV and high RDW). Normal value of RDW is 11.0-14.5%.

 

Determine the Cause

It’s crucial to understand what actually lead to developing iron deficiency. Colonoscopies, endoscopies and/or ultrasounds may be used if no clear reason for the deficiency is found. Adult men and postmenopausal women who have been diagnosed with iron deficiency anemia should have a colonoscopy to check for abnormalities. Testing for celiac disease should also be considered for adults with iron deficiency anemia. (R)

 

Treatment

Treatment requires not only restoring iron levels in the body, but also determining why iron stores got so low in the first place. If you don’t figure out why it happened, you’ll continue to have problems with iron deficiency anemia.

I’m always all about starting with nutrition, but it’s important to understand that eating more iron containing foods alone is usually not enough to treat iron deficiency anemia. (R)  That being said, it’s a good idea to eat more iron containing foods so that you don’t have to take as much supplemental iron.

 

Dietary Iron

First, it’s important to understand how much iron you need.

Recommended Dietary Allowance (RDA) for Iron (R)

Age

Male

Female

Pregnancy

Lactation

Birth to 6 months

0.27 mg

0.27 mg

7-12 months

11 mg

11 mg

1-3 years

7 mg

7 mg

4-8 years

10 mg

10 mg

9-13 years

8 mg

8 mg

14-18 years

11 mg

15 mg

27 mg

10 mg

19-50 years

8 mg

18 mg

27 mg

9 mg

51+ years

8 mg

8 mg

In developed countries, the average dietary intake of iron is between 10 and 15 mg each day. About 5-15% of this will be absorbed, which equates to about 1-3 mg per day and is a sufficient amount of iron if you're iron status is good. (R)

 

Heme and Non-heme Iron

There are two forms of dietary iron; heme and non-heme iron. Heme iron is found in hemoglobin and myoglobin of meat, fish, and seafood. Non-heme iron is found in vegetables, meat, and fortified foods like rice, cereal, bread, and other grain products. 20-30% of heme is absorbed, and less than 10% of non-heme iron is absorbed. Non-heme sources of iron are consumed in much greater quantities than heme iron around the world, which is why it’s important to understand how to increase the bioavailability of non-heme iron. (R)

Non-heme iron absorption rates can be regulated by the gut. The main hormone that influences the absorption rate is hepcidin.  Hepcidin decreases iron absorption. Inflammation increases the amount of hepcidin in the body, which means that if there is a lot of chronic inflammation, then their will be higher levels of hepcidin, which will decrease the amount of iron absorption.

 

Vitamin C

Consuming vitamin C (ascorbic acid) with iron is the most powerful way to increase iron absorption. Vitamin C increases the absorption of iron by up to 600%, which negates pretty much any iron absorption inhibitor (iron inhibitors are discussed below). 50 mg of vitamin C taken with a meal increases the absorption by 3 to 6 times. Vitamin C helps convert Fe3+ (ferric) to Fe2+ (ferrous) iron, which is the iron that is best absorbed. (R)

Learning how to pair vitamin C rich foods with iron rich foods is a very good thing to learn.

 

Omnivorous, Vegetarian and Vegan Diets

If you eat an omnivorous diet, you can expect to absorb approximately 14-18% of the dietary iron you consume. If you eat a vegetarian diet, you can expect to absorb about 5-12% of the iron you eat. (R)

Simply put, vegetarian and vegan diets usually contain enough iron to prevent iron deficiency anemia, but iron stores may be low. (R1) (R2

The main thing to understand with any diet, whether it includes meat or not, is to ensure you’re eating the right foods that provide you with all of the nutrients your body needs to thrive.

 

Dietary Sources of Iron

Food

Iron (mg)

%DV (18 mg/day)

Breakfast cereal fortified (varies)

1-22

0-100

White Rice (enriched), 1 cup

9.7

54

Oysters, 3 oz

8

44

White beans, canned, 1 cup

8

44

Dark chocolate, 3 oz

7

39

Beef liver, 3 oz

5

28

Lentils, cooked, ½ cup

3

17

Spinach, boiled and drained, ½ cup

3

17

Tofu, firm, ½ cup

3

17

Kidney beans, canned, ½ cup

2

11

Sardines, canned in oil, 3 oz

2

11

Chickpeas, boiled and drained, ½ cup

2

11

Tomatoes, canned, ½ cup

2

11

Ground beef, 3 oz

2

11

Potato, baked, flesh and skin, 1 medium

2

11

Cashew, 1 oz

2

11

Oatmeal, unfortified, ½ cup dry

1.6

9

Pistachios, dry roasted, ¼ cup

1.2

7

Green peas, boiled, ½ cup

1

6

Chicken, 3 oz

1

6

Bread, whole wheat, 1 slice

1

6

Bread, white, 1 slice

1

6

Raisins, seedless, ¼ cup

1

6

Spaghetti, whole wheat, cooked, 1 cup

1

6

Tuna, light, canned in water, 3 oz

1

6

Turkey, 3 oz

1

6

Broccoli, boiled and drained, ½ cup

1

6

Black strap molasses, 1 tsp

1

6

Rice, brown, cooked, 1 cup

1

6

In the US, fortified foods account for half of the dietary intake of iron. The iron used in fortified foods is about twice as less absorbable than ferrous sulfate (discussed below). (R)

For infants, breast milk does have iron, but it’s insufficient to meet the needs of infants who are 4 to 6 months or older. (R)

 

Iron Absorption Inhibitors

A healthy “balanced” diet (meat, fruits, vegetables, etc.) will basically be unaffected by inhibitors, because a meal might have some phytates in it, but it will also have vitamin C, which balances out the absorption rates. (R)

With that said, if you have iron deficiency anemia, you don’t want to take iron supplements with tea, coffee, or calcium (supplements or milk). Calcium may or may not inhibit iron absorption; it’s still being studied.

Other inhibitors are:

  • Flavonoids (R)
  • Oxalates (R)
  • Phytates (grains, nuts, seeds, and beans) (R)
  • Proton-pump inhibitors (R)
  • H2 antagonists. (R)

Removing the bran, soaking, sprouting, and leavening bread decreases phytates. But as I’ve already discussed, if you are consuming vitamin C rich foods with meals, than inhibitors shouldn’t really be an issue.

 

Iron Supplementation

Iron supplements can be found in different forms and contain different percentages of iron:

  • Ferrous fumarate contains 33% iron
  • Ferrous sulfate contains 20% iron
  • Ferrous gluconate contains 12% iron

These forms have been found to be fairly similar in terms of absorption and bioavailability.

Hemoglobin levels will start to increase after 1-2 weeks of starting therapy. Iron supplements are pretty safe, cheap, and effective. However, many people do not tolerate iron supplements, as they can cause abdominal discomfort, nausea, vomiting, constipation, and dark colored stools.  The side effects are caused by the high levels of free iron, which causes oxidative damage. Enteric-coated and delayed release iron supplements help to alleviate these side effects, but they are not absorbed as well. In severe cases, some need to receive iron intravenously. (R)

Supplemental iron combined with amino acids (chelated forms) are also absorbed better, and less affected by dietary inhibitors. Iron glycinate is a chelated form and has less side effects with better absorption than non-chelated forms. (R)

Adults with iron deficiency anemia are usually given 50-200 mg/day of elemental iron for 3 months, and children are given 6 mg/kg of body weight, depending on the severity. Iron supplementation is often continued for a 4-5 months after normal hemoglobin levels are established, to restore body stores. (Krause textbook) Once healthy levels of iron are restored and no symptoms are present, then you’re good to go.

 

High in Iron Meal Ideas

Note: you probably need iron supplements to correct iron deficiency anemia, but this diet is relatively high in iron, and a relatively “normal” diet as well.

Note 2: drink coffee and tea between meals, because they inhibit the absorption of iron

Breakfast

Option 1: orange juice, 1 cup iron fortified cereal (100% DV iron), milk of your choice, 2 slices of toasts (iron fortified bread), butter of your choice

Option 2: breakfast burrito with enriched/fortified tortilla, black beans, bell pepper, eggs, salsa, cheese

Option 3: oatmeal or overnight oatmeal with black strap molasses, dried fruit, milk of your choice, nuts and seeds of your choice

Lunch and Dinner

Option 1: Hamburger, baked beans, cantaloupe or other vitamin C rich fruit

Option 2: chicken breast, baked potato (eat the skin), broccoli

Option 3: spinach salad with sliced strawberries, chicken, green lentils, and quinoa

Option 5: tacos made with ground beef, fortified tortillas, tomatoes, lettuce, onion, avocado

Option 6: spaghetti (fortified or enriched) with ground beef, tomato sauce, broccoli, and bread (fortified or enriched)

 

Snacks

Option 1: trail mix with nuts, seeds, and dried fruit

Option 2: smoothie with 2 cups raw spinach, choice of fruit (banana, mango, blueberries, strawberries), milk of your choice, black strap molasses

Option 3: pistachios and an orange or other high vitamin C fruit