Can You Be Iron Deficient Without Anemia? Yes, and It’s Surprisingly Common
Key takeaways:
Many people don’t know they have iron deficiency until it leads to anemia (low blood counts). But anemia doesn’t happen until the later stages of iron deficiency.
Iron deficiency is a common problem in the U.S. It can be caused by any type of blood loss, restrictive diets, and a variety of stomach and intestinal problems.
Even without anemia, iron deficiency can still lead to serious symptoms like fatigue, depressed mood, hair loss, and headaches.
Table of contents
Iron deficiency without anemia is more common in the U.S. than you might think. A study published in 2024 found that nearly 1 in 3 adults had either low iron levels or couldn’t use the iron stored in their body.
Most people aren’t diagnosed with iron deficiency until it causes anemia (low red blood cell count). But anemia doesn’t arrive until you’ve had low iron for some time. And iron deficiency can still cause health problems on its own. That’s why it’s important to diagnose and treat iron deficiency without anemia before it causes more serious health issues.
What is iron deficiency without anemia?
Iron deficiency without anemia means you have low iron stores in your body (iron deficiency), but it hasn’t yet affected your blood counts (anemia).
When someone has low iron, it can start to affect the body’s ability to make new red blood cells. But it takes time for iron deficiency to lead to anemia. We’ll get into more specifics about iron deficiency without anemia. But first, it helps to understand the typical progression of iron deficiency:
Iron stores get depleted: In this first stage, there’s a decrease in something called ferritin. Ferritin is the protein that helps store iron in the body.
Less iron is circulating: As the iron stores get lower, less iron travels around in the bloodstream. At this stage, there’s a decrease in transferrin. Transferrin is the protein that carries iron to different parts of the body.
Blood counts start to drop: Your blood counts eventually drop because your iron stores are completely depleted. Or, it can also happen when you lose your ability to transport those iron stores.
So anemia is actually a late-stage complication of iron deficiency. In other words, the body spends some time in the iron-deficiency stages before it develops anemia.
What is low ferritin? This is usually the first sign of iron deficiency. But many healthcare professionals don’t even know to test for it.
Iron-rich foods: A balanced diet is an important way to prevent iron deficiency. But it helps to know the foods that help — and hurt — iron absorption.
Do you need an iron supplement? Our guide walks you through everything you need to know about the different supplements, plus the best way to take them.
What causes iron deficiency without anemia?
There are many different causes of iron deficiency without anemia. In general, iron deficiency can happen due to:
Not getting enough iron from your diet
Your body not absorbing enough iron
Blood loss, which causes you to lose iron from your body
Needing more iron than usual
Not getting enough iron
If you’re iron deficient, there are usually other reasons than your diet. Many iron-rich foods are common in the U.S. But not eating enough iron can still contribute to iron deficiency. It can happen in people with:
A health condition that severely limits their nutrition intake
A highly restrictive diet
Vegan and vegetarian diets, since our bodies absorb iron better from animal sources
Not absorbing enough iron
Certain intestinal conditions can cause your body to not absorb the amount of iron you need. For example:
Celiac disease
Gastritis (inflammation of the stomach lining)
H. pylori infection
A history of bariatric surgery (for weight loss)
Also, some medications can prevent your body from absorbing iron. That’s true if you take the following medications daily:
Tetracycline
Antacids
NSAIDs (nonsteroidal anti-inflammatory drugs)
Blood loss
Blood loss leads to iron loss from your body. And it’s one of the most common causes of iron deficiency. Blood loss occurs with:
Menstruation
Bleeding from the stomach or intestines, like from ulcers or diverticula (pouches in your colon)
Colon cancer
Hemodialysis (a treatment that filters waste from your blood)
Recent surgery
You also lose blood if you’re regularly donating blood or having blood drawn for lab work.
Increased iron needs
If you need more iron than usual, your iron stores will be used up at a quicker rate. The following conditions increase the amount of iron your body needs on a daily basis:
Pregnancy
Lactation
On top of that, conditions like pregnancy and lactation can also lead to blood loss. So not only do you need more iron, but you’re also losing it at a faster rate.
What are the symptoms of iron deficiency without anemia?
Even if your blood counts are normal, iron deficiency alone can cause pretty significant symptoms. These include:
Fatigue
Not having energy to exercise
Craving for ice or other non-food items (also called pica)
Hair loss
Headaches
Trouble concentrating
When iron deficiency progresses to anemia, the symptoms can become even more severe. They can include symptoms like shortness of breath, heart palpitations, and dizziness.
How is iron deficiency without anemia diagnosed?
Iron deficiency is diagnosed with a blood test. It's a little more complicated than just measuring the amount of iron in your blood. In fact, your iron levels aren’t actually used to diagnose iron deficiency.
When a healthcare professional is testing someone for iron deficiency, they may check a number of different blood tests. But the two that are most helpful are:
Ferritin
Transferrin saturation
We’ll go into both of these in more detail below.
Ferritin
Testing for ferritin is the most useful first step in diagnosing iron deficiency. As mentioned above, ferritin is the protein that stores iron in the body. And a low ferritin level is the first sign of iron deficiency. There’s no firm cutoff for a normal ferritin level. But most healthcare professionals diagnose iron deficiency when ferritin is below 30 ng/mL.
But it's possible to have a normal or even high ferritin level and still be iron deficient. This is because ferritin levels increase whenever there’s inflammation in the body. Some health conditions cause inflammation, including:
Autoimmune conditions
Infections
Increased body fat
Liver disease
Heart failure
Cancer
If you have one of these conditions, your ferritin level can look normal when in fact your body is still iron deficient.
Transferrin saturation
If you have one of the above conditions that affects ferritin, transferrin saturation is the next best test. This is the percentage of iron in your blood that is bound to transferrin. This is the protein that carries iron to different parts of your body. So, if you have low levels of transferrin saturation, then your iron stores aren’t being distributed to the parts of your body that need it.
On the test, any number less than 20% means you’re probably iron deficient.
How is iron deficiency without anemia treated?
Iron deficiency is treated with oral iron supplements. There are a few different types, but they all raise your iron levels in a similar way. The main supplements are:
Ferric citrate
Ferrous fumarate
Ferrous gluconate
Ferrous sulfate
Side effects & dosing
Side effects from oral iron supplements are common. They can include upset stomach, nausea, and changes in stools. Serious side effects are rare, especially if you take the recommended dose.
The dosing schedule differs from person to person. This is based on the type of iron you take and your degree of iron deficiency. It usually takes several weeks to months of treatment to get your iron stores back to normal.
Ongoing treatment
Your healthcare team will monitor your blood tests to determine when you no longer need treatment. If the cause of your iron deficiency is ongoing — like heavy menstrual bleeding — you may need to take iron supplements for the long term. But you’ll likely be able to cut back on your dose once your iron levels are normal.
In some cases, people need treatment with an iron infusion, where you get iron through an IV. But this isn’t a first-choice treatment. Someone might need iron infusions in more severe cases when their iron needs to be replenished quickly. Some people also need this when they're not able to take or tolerate oral iron.
It's important to follow the guidance of your healthcare team when taking iron supplements. They can help you manage any side effects, potential medication interactions, and avoid any toxicity from high doses.
Frequently asked questions
Yes, iron deficiency can lead to headaches. Headaches — especially migraines — are more common with iron-deficiency anemia. But they can occur in the earlier stages of iron deficiency as well.
The relationship between iron deficiency and weight is complicated. There’s some evidence that iron deficiency is associated with increased body weight. But it's unclear if iron deficiency causes weight gain, or if increased body fat affects iron stores.
Interestingly, one small study showed that women with iron deficiency lost weight when treated with iron supplements.
Iron-deficiency anemia can affect the color of your eyelids. It can make the inside of your eyelids look less pink and more pale than normal. This is related to the amount of circulating red blood cells. So, this sign is more likely when iron deficiency starts to affect your blood counts, causing iron-deficiency anemia.
The bottom line
Iron deficiency is more common than previously thought. And it can cause serious health issues. The problems can happen even before low iron levels affect your blood counts and cause anemia. Signs of iron deficiency can include feeling more tired than usual or having trouble exercising. If you experience these, talk to your primary care provider about getting tested for iron deficiency. Treatment with iron supplements will prevent more severe deficiency that leads to anemia.
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References
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Ciulei, M. A., et al. (2023). Iron deficiency is related to depressive symptoms in United States nonpregnant women of reproductive age: A cross-sectional analysis of NHANES 2005-2010. The Journal of Nutrition.
Coates, A., et al. (2017). Incidence of iron deficiency and iron deficient anemia in elite runners and triathletes. Clinical Journal of Sport Medicine.
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Pavord, S., et al. (2020). UK guidelines on the management of iron deficiency in pregnancy. British Journal of Haematology.
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Singh, R. K., et al. (2023). Association between iron deficiency anemia and chronic daily headache: A case-control study. Cephalalgia.
Tawfik, Y. M. K., et al. (2024). Absolute and functional iron deficiency in the US, 2017-2020. JAMA Network Open.
Tayyebi, A., et al. (2019). Is there any correlation between migraine attacks and iron deficiency anemia? A case-control study. International Journal of Hematology-Oncology and Stem Cell Research.
