When Should I Worry About...

What Causes Iron Deficiency & How to Know If You Have It

Nov. 30, 2022 - Katie McCallum

If you're struggling with unexplained fatigue or weakness and looking for the root cause, you may find yourself wondering if low iron could be the culprit.

"Iron is an essential mineral that helps your body carry out a number of important processes," explains Dr. Zuleikha Tyebjee, a primary-care physician at Houston Methodist. "One of the most essential roles iron plays is helping make and maintain healthy blood."

Iron is needed to form hemoglobin, a protein in red blood cells responsible for carrying oxygen throughout the body. This is an important job, so it's easy to see how being deficient in iron can come with consequences.

"Low iron levels can result in your tissues and organs getting insufficient oxygen-rich blood, which is called iron deficiency anemia," says Dr. Tyebjee. "Iron deficiency often causes only mild symptoms, but — left undiagnosed and untreated — it can affect a person's quality of life and, while rare, even be a sign of a serious health issue."

What isn't rare, though, is the prevalence of iron deficiencies, especially in women. According to the American Academy of Family Physicians, between 12 and 20 percent of women have iron deficiency anemia.

Who exactly needs to be most worried, how to tell if you're experiencing symptoms of low iron, what iron deficiency treatment looks like — Dr. Tyebjee explains all.

Why does iron deficiency occur?

"Iron is naturally present in many of the foods we eat, and our bodies store what we don't immediately need," says Dr. Tyebjee. "But these stores can become depleted, for a number of reasons."

Diet, of course, can affect iron levels — but this isn't as common in the U.S. as it is in other places in the world. Instead, American low iron levels are typically related to blood loss or inadequate absorption of iron.

Potential causes of iron deficiency include:

  • Heavy menstrual cycles
  • Pregnancy, whether due to the body making more blood to support the growing baby or blood loss during delivery
  • Decreased ability to absorb iron, which can be due to certain health conditions (Celiac disease, inflammatory bowel disease, H. pylori infection) or weight loss surgery
  • Low-dietary iron intake, though this is rare in the U.S.
  • Chronic bleeding in the gastrointestinal tract

"Blood loss is generally the most common reason for low iron levels," says Dr. Tyebjee. "Some of the causes are more serious than others, so it's important to take this deficiency seriously in case the root cause needs to be identified and treated."

She adds that all pregnant woman are at risk for iron deficiency, which is why prenatal vitamins often contain iron. Even still, it's important to work with your doctor to check for deficiency at the various stages of pregnancy in case additional supplementation becomes necessary.

What are the signs of iron deficiency?

In most cases, being low on iron causes only mild symptoms — if any symptoms at all.

However, if depletion continues and progresses to iron deficiency anemia, the prevalence and severity of symptoms can increase, too.

Low iron symptoms can include:

  • Fatigue
  • Weakness, especially during physical activity or exercise
  • Irritability
  • Headaches
  • Chest pain or trouble breathing
  • Unusual cravings, such as for ice chips
  • Restless leg syndrome

"Let your doctor know if you're experiencing any of these symptoms," recommends Dr. Tyebjee. "Fortunately, testing for low iron is as easy as doing some blood work."

How is iron deficiency diagnosed and treated?

If low iron is suspected, diagnosing or ruling out a deficiency starts with a physical exam, questions about your medical history and some blood tests.

Several blood-based tests can be used to check iron levels, including measuring ferritin (a protein that stores iron) and transferrin saturation (a protein that transfer iron to red blood cells). Low levels of these proteins are suggestive of iron deficiency anemia.

"In some cases, a person may not have symptoms, but we catch a potential deficiency through routine blood work, when we see the results of the complete blood count (CBC)," adds Dr. Tyebjee. "The iron-specific blood tests are then used to determine whether a deficiency truly exists."

Fixing an iron deficiency depends on the cause and severity. Iron pills are often the first step but in some cases, a multivitamin containing iron may be all that's needed.

"Oral iron supplementation is a safe, inexpensive and effective way of treating most cases of iron deficiency anemia," says Dr. Tyebjee. "It typically takes about six months of supplementation for iron stores to return to normal. For the more permanent reasons of deficiency, such as weight loss surgery, iron supplements may need to be taken long-term."

Your doctor will recommend the type of oral iron that works best for you and provide a schedule and tips for taking iron effectively.

It's also important to find out why your iron was low in the first place. For some causes of deficiency, iron pills alone will never be enough. And while rare, it can sometimes be a sign of serious health condition.

"Sometimes we know why someone might be deficient — pregnancy, heavy menstrual bleeding or a known reason for reduced iron absorption," explains Dr. Tyebjee. "When the cause isn't clear, however, additional tests are needed to determine whether an underlying issue is present. We never want to leave gastrointestinal tract bleeding undiagnosed, for instance."

If there is a chronic or insidious root cause, identifying and treating it is critical for managing both your overall health and iron deficiency long-term.

What foods should you eat for iron deficiency?

Most Americans have no trouble getting enough iron through the foods they eat — so much so that diet modification isn't typically thought of as a strategy for treating iron deficiency.

Still, there's certainly no harm in making sure your diet is optimized for iron intake, whether you're deficient or not.

Foods high in iron include:

  • Lean meats, scallops and poultry
  • Iron-fortified breakfast cereals and breads
  • Most types of beans, lentils and peas
  • Nuts and seeds, including almonds, sunflower seeds and peanuts
  • Certain fruits, such as dried prunes, dried peaches and prune juice

"Iron is present in much of the food we eat and, as mentioned, our bodies store it away for future use as well," explains Dr. Tyebjee. "Because of this, most people — even those who don't eat meat — don't need iron supplementation unless they have a health issue that reduces iron absorption or causes bleeding."

And one last important point: If you're still worried about your iron levels, it's important to consult your doctor before trying an iron supplement — or even a multivitamin containing iron — since getting too much iron can come with problems of its own.

(Related: Do Multivitamins Actually Do Anything?)

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Categories: When Should I Worry About...