Fatigue? Anxiety? Insomnia? Could be Iron Deficiency

by | | Female Hormones


I see a patients every week with iron deficiency who don’t know it.  Standard blood work isn’t enough.  In this article I’ll explain why.  There are several markers that help us understand why iron is low but again conventional medicine rarely tests these.  Low iron can cause fatigue,  anxiety, depression and insomnia just to name a few common symptoms.


“My doctor says its all in my head but I know it isn’t.”


Other symptoms of iron deficiency include palpitations, rapid heart rate, restless legs, infections, poor mental function brain fog and decreased tolerance for exercise.  Athletic performance and capacity to work will be lower.  This is because when iron is low it decreases oxygen availability and then myoglobin levels in muscle drops.  Lactic acid builds up. 

It can also be difficult to maintain proper body temperature.  This can lead people to believe they have a thyroid problem.  Brittle nails, sores around the mouth and loss of taste can occur. Iron deficiency happens prior to clinical anemia which is the final stage.  Eight percent of premenopausal women are iron deficient but I’m guessing this number is more given the number of women I see who are undiagnosed.  A quarter of those are anemic.

In clinic I listen carefully to my patients symptoms and teach them how to read their own signs.  Iron deficiency is often visible in a person’s complexion, cuticles or tongue depending on what else is going on.  Postural hypotension or feeling dizzy upon standing can be a tell-tale symptom.


Functional Medicine Solutions

That being said, I always want to see comprehensive lab work.  This is the best way to know what is actually going on.  Recently I suspected a patient to be low in iron but her lab work showed two parasitic infections with healthy iron stores.  As we treated the gut infections, her complexion and energy changed rapidly. 

Another patient had a chief complaint of anxiety and fatigue.  This had been going on for 4 years, since the birth of her second child.  Her ferritin was the lowest I’ve ever seen.  She is in the final stage of iron deficiency and clinically anemic.

Why is ferritin not monitored more closely, especially in mothers?

In the final trimester before my son was born I was also anemic.  My symptoms were so uncomfortable I would cry at night before bed knowing I faced another night without sleep and in pain.  Restless legs and insomnia can be incredibly painful. 

This could have been caught earlier and prevented.  I was seeing a primary care provieder weekly so why was this missed?  I trusted that my bloodwork was being monitored properly.  My diet was excellent but at this stage more supplementation was needed.  Once I began I felt better within a few days.


3 Stages of Iron Deficiency

There are three stages of iron deficiency.  Iron stores are measured in ferritin.  When ferritin is between 10 to 15 ng/mL there is deficiency but not exhaustion.  During this stage, there may not be any symptoms that conventional medicine would recognize. 

The difference in Functional Medicine is that we flag anything under 30 ng/mL. In this way we prevent stage two when iron stores become exhausted and ferritin drops below 10 ng/mL.

The final stage is when there is no iron in bone marrow stores.  Red blood cell production and hemoglobin drop.  Anemia is more obvious, and symptoms can become severe. Unfortunately, most clinicians in primary care settings don’t test iron or ferritin. They only look at hemoglobin, red blood cells, and MCV levels.  This is why a lot of patients in stage one and stage two are being missed. 

In fact, its fairly common that people are iron deficient for decades without knowing it.  Iron deficiency affects 1.62 billion people worldwide.  That’s 25% of our global population.

Functional medicine understands there is a connection between depression, anxiety, fatigue, insomnia and low iron.  Observing a patient and feeling the pulse is often enough to suspect iron deficiency.  This is part of my basic training. 

We also know how to investigate the underlying cause.  Is it simply lack of nutrient intake?  How can we increase iron rich foods into the diet?  What other lifestyle factors are contributing?  Is there gut dysbiosis leading to malabsorption?  Are there any infections that need to be cleared?  Is the body shunting iron to protect from something more serious?  Is heat masking some of the signs we check?



Ferritin is an acute-phase reactant that increases the inflammatory response much like C-reactive protein.  This can be confusing and its why a comprehensive panel is important to have. This is especially when chronic pain or more complex conditions are present. So a patient can be iron deficient but their inflammation  is raising ferritin.  Seeing a normal value in the face of clinical anemia does happen.  Functional testing catches this by looking deeper.

In many places people can order their own bloodwork but the interpretation is important.  I ask patients to get copies of their labs so we can look over them together from a Functional perspective.

The spirit of ‘DIY’ or ‘do it yourself’ is a quality I admire in patients.  I love working with people who are engaged in their health and want to understand what is at the root of what they are experiencing.



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