Low Ferritin, Normal Hemoglobin: Can I Still Be Iron Deficient?
A blood test showing normal hemoglobin doesn't rule out iron deficiency. Ferritin, which measures your iron stores, usually drops much earlier and is the first to raise the alarm.
Hemoglobin and Ferritin: What Each One Measures
Hemoglobin is the protein that carries oxygen inside red blood cells. Think of it as a fleet of trucks. Outside of pregnancy, the WHO defines anemia as a level below 12 grams per deciliter in women and below 13 in men.
Ferritin is the protein the body uses to store its reserve iron. If hemoglobin is the trucks, ferritin is the warehouse.
Why Hemoglobin Can Be Misleading
The warehouse empties long before the trucks start running short. The body uses up its reserves to keep the fleet on the road. That's why you can go for months with perfect hemoglobin and very low ferritin: feeling tired, but with no anemia on paper.
The WHO sets iron deficiency in adults at a ferritin level below 15 micrograms per liter. Many doctors already suspect it once it falls below 30.
The Inflammation Trap
Ferritin also rises with inflammation. An infection, obesity or arthritis can push it up and hide an empty warehouse. In these cases, the WHO raises the threshold to 70.
On top of that, a routine blood test doesn't always include ferritin. If you have symptoms, ask your doctor whether it should be tested.
Four Signs Few People Link to Iron
Restless legs: at night, your legs feel an urge to move and keep you from sleeping. The brain uses iron to make dopamine, and a shortage is associated with restless legs syndrome.
Weak nails: they become thin, break easily or sink in the middle like a small spoon.
Mouth and tongue: cracks appear at the corners of the mouth and the tongue becomes smooth and sore.
Craving ice to chew: this is called pagophagia and is very typical of this deficiency. The most widely studied hypothesis is that chewing something very cold may send more blood to the brain and give an alertness boost to someone who is exhausted. It usually goes away once iron levels are restored.
Common Causes and How to Absorb Iron Better
The most common causes are heavy periods, pregnancy, frequent blood donation, a poorly planned vegetarian diet or celiac disease, which prevents the body from absorbing it.
Iron from meat and fish is absorbed much better than iron from legumes. To make the most of plant-based iron, pair it with raw bell pepper or an orange. Wait an hour before having coffee or tea: their polyphenols block absorption.
Spinach is not the great source of iron its reputation suggests. It does contain iron, but its oxalates hold back absorption.
When to See a Doctor
Taking iron on your own is not harmless. It can mask blood loss that no one has looked for, and any excess builds up in the liver. The dose should be decided by a doctor.
See a doctor if your stools are black, if you soak through a pad every hour for several hours in a row, or if you get short of breath climbing a single flight of stairs. In a man, or in a woman who doesn't have periods, iron deficiency means looking for where blood is being lost, often in the digestive tract.
Frequently asked questions
Can I be iron deficient with normal hemoglobin?
Yes. Your iron stores, measured by ferritin, run out before hemoglobin drops, so you can be deficient without showing anemia on a blood test.
What ferritin level indicates iron deficiency?
The WHO sets it at below 15 micrograms per liter in adults, and many doctors already suspect it below 30. If there is inflammation, the WHO raises the threshold to 70.
Why does iron deficiency make you want to chew ice?
It's called pagophagia. The most widely studied hypothesis is that the cold may send more blood to the brain and give an alertness boost to someone who is exhausted.
Is it a good idea to take iron supplements just in case?
No. They can mask undiagnosed blood loss and any excess builds up in the liver, so the dose should be decided by a doctor.
Informative article written with the help of AI tools from the verified script of the video. The video is in Spanish.