If you've recently gotten a blood test and your levels of hemoglobin — the iron-containing protein in your blood that transports oxygen around your body — came back too low, you may have a condition called iron-deficiency anemia, or low iron levels.
A normal range of hemoglobin in healthy adults is anywhere from 11.6 to 16.6 grams per deciliter (g/dL), per the Mayo Clinic. Anything below that could be considered anemia (depending on the person, their symptoms and other underlying health conditions). An iron level of 5 g/dL, for example, is too low.
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Here, learn the causes of iron-deficiency anemia, whether an iron level of 5 g/dL is dangerous and different treatments for iron deficiency.
What Iron Levels Are Dangerous?
Any iron level less than 11.6 g/dL is considered anemia for most healthy adults, per the Mayo Clinic. Most of the time, if iron-deficiency anemia is treated properly, it is not dangerous.
But what level of untreated iron-deficiency anemia is considered dangerous?
While an iron level of 10 g/dL is not too far below the "normal" range (and can be easily restored), an iron level of 5 g/dL might be dangerous and lead to health complications if left untreated, including:
- Irregular heartbeat (and other heart issues)
- Chronic fatigue
- Pregnancy complications
- Developmental delays in children
That said, too much iron in your blood can also be dangerous and toxic, leading to a condition called hemochromatosis (or iron overload), per the Cleveland Clinic.
Hemochromatosis is usually diagnosed differently than iron-deficiency anemia because, unlike anemia, your hemoglobin levels can be within a "normal" range with hemochromatosis, per an April 2020 study in Cureus.
Instead, doctors will often measure your serum ferritin levels (the amount of iron stored in your liver) instead of hemoglobin. Serum ferritin levels tend to be greater than 250 nanograms per deciliter if you have the condition, per Merck Manual.
Hemochromatosis can lead to the following complications:
- Irregular heartbeat
- Heart failure
- Cirrhosis (scaring of the liver)
- Enlarged liver
- Liver cancer or failure
- Gland issues
- Reproductive issues (erectile dysfunction or early menopause)
- Gray-looking skin
Hemochromatosis can be genetic or caused by certain health conditions (like liver disease, fatty liver or Hepatitis C). It can also be caused by common iron-deficiency treatments, like blood transfusions, kidney dialysis and iron pills or injections, per the Cleveland Clinic.
What Causes Iron-Deficiency Anemia?
Anemia happens when you have a low level of hemoglobin in your cells, per the Mayo Clinic. One common type of anemia is iron-deficiency anemia. This happens when there's not enough iron in your blood, which keeps your body from making enough healthy red blood cells, per the National Institutes of Health.
A few causes of iron-deficiency anemia include the following, per the Mayo Clinic:
1. Lack of Iron in Your Diet
Not eating enough iron-rich foods can cause a deficiency. Some examples of iron-rich food include meat, eggs, leafy greens and iron-fortified whole grains.
People at risk for this include those who don't eat animal products or otherwise severely restrict their food intake.
People who are pregnant need to share their body's iron stores with their baby, which can deplete their own levels quickly. This is why prenatal vitamins with iron are typically recommended for people who are pregnant.
People who are pregnant and give birth are also at higher risk of iron-deficiency anemia. In fact, it affects 1 in 6 pregnant people, according to the Office on Women's Health.
3. Internal Bleeding
When you have any form of blood loss, you lose iron, including when you bleed internally. Conditions like peptic ulcers, hernias, colon polyps and colorectal cancer can cause chronic blood loss, which leads to iron-deficiency anemia.
Likewise, if your GI tract is bleeding (from overuse of over-the-counter pain relievers like aspirin, for example) you can get anemia.
4. Heavy Menstrual Bleeding
If your blood flow is heavy during your period, you may lose enough blood to cause low iron levels. This is especially true for people with endometriosis — a condition where uterine lining grows outside of the uterus, per Johns Hopkins Medicine — who tend to have heavy menstrual bleeding.
People with uterine fibroids — benign growths on the muscles of the uterus — may also bleed heavily during menstruation, per the Mayo Clinic.
5. Inability to Absorb Iron
Sometimes if you have a chronic illness like celiac disease, you are unable to absorb iron through your small intestine and into your bloodstream. In fact, any condition that keeps you from absorbing nutrients from your food could cause anemia.
You could also be unable to absorb iron if you've had surgery to remove or bypass part of your intestines (i.e., gastric bypass surgery).
Who's at Risk for Iron-Deficiency Anemia?
There are some groups of people at a greater risk of iron-deficiency anemia than others. These include the following, per the Mayo Clinic:
- People assigned female at birth (AFAB), because they may have heavy menstrual bleeding or iron loss during pregnancy
- Infants and children
- Frequent blood donors
Iron-Deficiency Anemia Symptoms
There are many different low-iron symptoms to look out for, including the following, per the Cleveland Clinic:
- Shortness of breath
- Chest pain
- Difficulty concentrating
- Restless legs syndrome (a condition that causes an uncontrollable urge to move the legs, per the Mayo Clinic)
There are also some "weird" signs of iron deficiency that are worth pointing out, including the following, per the Cleveland Clinic:
- Pica (a condition where people crave non-food items, like ice, chalk, clay or starch)
- Cracks at the corners of your mouth
- Pale skin (or paler than usual)
- Sore, painful tongue
- Cold hands
- Brittle nails that often form a spoon shape (a condition called koilonychia)
How Is Iron-Deficiency Anemia Diagnosed?
Any iron level less than 11.6 g/dL is considered iron-deficiency anemia, the Mayo Clinic.
To determine if your levels are this low (even 5 g/dL), your doctor may do a few different tests, including the following, per the NIH:
1. A Complete Blood Count (CBC) Test
This is usually the first kind of test doctors will order if you come to their office with anemia symptoms. Sometimes, doctors will even order it as part of your routine physical checkup. A CBC test will give you your:
- Red blood cell count
- White blood cell count
- Hemoglobin (iron) levels
- Hematocrit levels
- Platelet levels
Your hemoglobin blood test results, your hematocrit level and the size of your red blood cells will confirm whether you have anemia. Both hemoglobin and hematocrit are often low in people with anemia, and red blood cells are often smaller than normal in people with iron-deficiency anemia, per the NIH.
2. Additional Blood Tests
Once you've gotten a CBC test, your doctor may request more blood work to figure out how severe your iron-deficiency anemia is.
These tests can determine your ferritin level (a protein in your blood that has iron, per the Mayo Clinic) and your total iron-binding capacity (the amount of protein that helps transport iron, per Mount Sinai).
There are also tests to determine internal bleeding (endoscopy, colonoscopy, ultrasound, etc.), if your doctor thinks this is the cause of your low iron levels.
Treatment for Iron-Deficiency Anemia
There are a few different treatment options for iron-deficiency anemia, depending on how severe your deficiency is. These can include the following, per the NIH:
1. Iron Pills
Taking an iron pill (aka, iron supplement) can help increase iron levels for some people (although these supplements aren't helpful for people who are deficient because of malabsorption). This method will take several months to restore your levels, per the Mayo Clinic.
Side effects of iron pills typically include dark urine, constipation and upset stomach. While you should try to take iron pills on an empty stomach (for better absorption), you can also take them with meals if they upset your stomach, per the Mayo Clinic.
An important note: Do not take iron pills unless your doctor recommends it. Taking too much can lead to iron overdose.
It's also recommended to avoid taking antacids with your iron pills. And for better absorption, take your iron with a source of vitamin C, like a glass of orange juice or vitamin C supplement, per the Mayo Clinic.
2. Iron IV
Sometimes doctors will recommend getting iron intravenously, or through an IV needle. This option is good for people who have underlying conditions that make it difficult to absorb iron through pills, like celiac disease, inflammatory bowel disease or cancer, per the Cleveland Clinic.
Typically, you'll only need one or two doses over the course of a few weeks to restore your levels.
Side note: You may feel nausea or headaches after receiving an iron IV. But both should go away after a day or two.
3. Certain Medications
Your doctor may prescribe a medication called an erythropoiesis stimulating agent (ESA) if your bone marrow doesn't have enough iron to make sufficient hemoglobin. You may have to take this with other iron treatments, especially if you have a chronic health condition.
4. Blood Transfusions
If your iron-deficiency anemia is severe, your doctor may recommend a blood transfusion. This is a quick way to restore iron levels, but it is only necessary in people with acute cases or other underlying conditions.
5. Surgery to Treat Internal Bleeding
If internal bleeding is causing your iron-deficiency anemia, you may need surgery to help stop it.
How to Prevent Iron-Deficiency Anemia
One of the best ways to prevent an iron deficiency is by eating plenty of foods high in iron, including some of the following, per the Mayo Clinic:
- Red meat, poultry and pork
- Dark, leafy greens (like spinach)
- Dried fruit (raisins or apricots)
- Iron-fortified cereals, breads or pastas
If you're a vegan or vegetarian, try to find plant-based foods that are rich in iron. And if you're someone with high cholesterol, talk to your doctor about nutritious meat options that won't increase your levels.
You could also try eating foods high in vitamin C alongside iron-rich foods, to help the iron better absorb into your bloodstream. Orange juice is a great first option, but other foods high in vitamin C include the following, per the Mayo Clinic:
- Leafy greens
Because leafy greens are rich in iron, you might try eating a salad topped with peppers and/or dressed with a homemade citrus vinaigrette.
To prevent iron deficiency in infants, make sure they are getting breastmilk or iron-fortified formula within the first year. After six months, start feeding your baby iron-fortified cereals or puréed meats to help increase their iron levels, per the Mayo Clinic. Make sure children also eat iron-rich foods as they grow.
When to See a Doctor
In most cases, iron-deficiency anemia that's just below the "normal" range of hemoglobin levels (11.6 g/dL to 16.6 g/dL) is considered mild, easily treatable and is not dangerous if treated properly.
If your iron levels are much lower than "normal," like 5 g/dL, for example, you can develop dangerous long-term health effects if you don't treat it.
If you feel any symptoms of low iron, go to the doctor to get a blood test. They can figure out if you need to take iron pills or get other treatments.
- National Institutes of Health: "Iron-Deficiency Anemia"
- Mayo Clinic: "Anemia"
- Johns Hopkins Medicine: "Endometriosis"
- Mayo Clinic: "Restless Leg Syndrome"
- Cleveland Clinic: "Iron-Deficiency Anemia"
- Mayo Clinic: "Ferritin Test"
- Mount Sinai: "Total Iron Binding Capacity"
- Cleveland Clinic: "Hemochromatosis"
- Office on Women's Health: "Iron-deficiency anemia"
- Mayo Clinic: "Uterine Fibroids"
- Merck Manual: "Hereditary Hemochromatosis"
- Cureus: "Polycythemia and Anemia in Hereditary Hemochromatosis"
- Cleveland Clinic: "Iron Infusion"