Written by Stormy Fanning, RN, MSN
Most adults over 40 and women over 30 have had their iron and/or ferritin tested by a lab at some point. But what do those words and numbers actually mean? Let’s dig deeper.
What does iron do for the body?
Iron is a mineral absorbed from food. It is essential to several bodily functions; most importantly, it is used in the production of hemoglobin (Hgb), the red blood cell that carries oxygen from the lungs to the cells. This supports energy levels and reduces fatigue. Iron also supports thyroid function, muscle function, memory2, and helps hair and nails to grow, among many other things.1
Why would iron levels be low?
A common cause of low iron is inadequate dietary intake.2 This can include
more factors than simply not eating enough iron. If you search for foods high
in iron, the first food on most lists is iron-fortified cereals. However, if
you researched iron absorption, you would find that vitamin D, added to most kinds of milk, significantly decreases the amount of iron absorbed. So, cereal is a good source of iron until you put milk on it.
Coffee and tea contain a compound known as flavonoids. These also decrease the absorption of iron from plant-based sources, such as spinach and legumes.5 Drinking them with or close to the meal will decrease the amount of iron your body gets.
Flavonoids do not affect the absorption of iron from animal sources, such as
red meat and shellfish.
People who take certain medications for acid reflux do not absorb as much iron from their food.2 These include a group of drugs known as H-2 blockers
(famotidine/Pepcid, ranitidine/Zantac) and proton pump inhibitors
(omeprazole/Prilosec, pantoprazole/Protonix, esomeprazole/Nexium).
What is ferritin?
Ferritin is a protein that stores iron in the cells. Iron ingested by diet or supplement is absorbed into the bloodstream and eventually stored in ferritin. The body will produce more ferritin in response to increased iron levels. Ferritin stores the iron as a reserve and releases it when the body needs it for
functions.3 However, the storage process is slow and can take
several days. This means that if you took your iron supplement for the last
three days and got your blood checked today, your serum (blood) iron level
would be normal or high. However, if you had low iron intake for three months
before that, your ferritin level would still be low.
This is why it is important to check both lab values. Since the body makes ferritin in response to iron levels, the most common cause of high ferritin is high iron.3 The most common cause of high iron is too much iron supplementation.
Ferritin can be raised above normal levels in certain other conditions, such as liver disease, inflammatory processes like rheumatoid arthritis, hyperthyroidism, and some types of cancer.4 If you have a high ferritin level, before you panic that you might have cancer, check your vitamins. Iron is added to many multivitamins, and as just stated, the most common cause of high ferritin is excess iron supplements.3
What are the symptoms of low iron?
The symptoms of low iron compose quite a list: fatigue, depression, impaired
memory, palpitations, shortness of breath, decreased activity tolerance, joint
pain, muscle weakness, restless leg symptoms, hair loss, weight gain, and pica.2 Not everyone has all or even most of these symptoms, making iron deficiency challenging to identify.
Pica is the compulsive eating of a non-food substance, typically ice or dirt.2 This symptom is usually specific to low iron and is easily identified. Shortness of breath and decreased activity tolerance are a result of low oxygen levels in
the blood due to low hemoglobin (anemia), which was caused by inadequate iron.
If you have those symptoms, your provider will likely check your iron and
ferritin. This condition, known as iron deficiency anemia, is easily treated
with supplemental iron.
Understanding lab values
After your provider sends you to get your blood checked for iron and ferritin, they will call you with the results. They may tell you that your level is low and
recommend a supplement. They may tell you ‘everything looks good.’ If you are like me, you want some more specific input than that.
If you have access to your patient portal, you can see all your lab results. Next to your result, there should be a reference range for that value. Labs have different reference ranges depending on their equipment and testing materials. Your lab may say that normal iron is 60-170 micrograms per deciliter (mcg/dL). If your value for serum iron is 65, that would be considered a normal value. As you can see, that is still a relatively low value considering the wide range for normal. You may still have symptoms and need supplements or increased dietary intake. Everyone is slightly different and should be treated according to symptoms as well as lab results.
If you begin taking an iron supplement, read the labels carefully. Some supplements contain an extremely high dose of iron (as much as 325 mg or 600% of the daily value) and should not be taken every day. For most people, a lower dose taken 3 days a week will be sufficient for iron deficiency.
Adjust your dose or frequency and track how you feel. Improved health and increased energy will soon be in your day.Resource
1 “7 Reasons to Treat Low Ferritin Levels: Step-by-Step Treatment Guide” by Dr. Westin Childs, published October 28, 2022
on www.restartmed.com/low-ferritin/
2 “Iron deficiency without anaemia: a diagnosis that matters” by
Abdulrahman Al-Naseem, Abdelrahman Sallam, Shamim
Choudhury and Jecko Thachil. Published in Clin Med March 2021. DOI: https://doi.org/10.7861/clinmed.2020-0582
3 1998-2024 Mayo Foundation for Medical Education and Research (MFMER).
4 “Causes of High Ferritin” www.newhealthadvisor.org/Causes-of-High-Ferritin.html
5 “Tea and Iron Absorption” by Dr. Megan Rossi. Published August 19, 2021 on www.theguthealthdoctor.com/tea-iron-absorption
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