All About Iron: how iron absorption works, what’s driving your iron deficiency & why standard iron supplementation isn’t the answer
One of the things Julie and I consistently see in our naturopathy clinics, regardless of the symptoms that brought the patient to see us, is iron deficiency.
Whether it’s a mild deficiency, or a new result on your blood test, or a case of “I’ve always been iron deficient, and nothing seems to get my levels up" — we see it!
And there are some key things we want EVERYONE to know about iron.
(1) Iron deficiency is generally not correctly diagnosed, because Iron Studies are often not interpreted correctly, or blood tests are missing data or the results are skewed from other factors. This is especially true for pregnant people.
(2) The way to correct iron deficiency is not through high dose, daily iron supplementation. In fact, too much iron in the body can be harmful.
(3) In the case of true iron deficiency, not eating enough red meat or your regular menstrual period are likely blamed. But dietary intake and menstruation are rarely the underlying, root-cause culprits of your low iron levels.
(4) Iron absorption and metabolism is a complex, tightly controlled process in your body. We have research from the last decade that reveals some key details about the regulation of iron in your body, however, this research is not yet implemented into current clinical practice.
The Iron Story
Iron! An important and incredibly nuanced mineral. The short story is too little iron is no good, and too much iron is no good. As such, our bodies have very sensitive mechanisms to regulate iron absorption. Let’s start by understanding iron’s function, and what we look at when assessing iron stores on a blood test.
Iron’s Function
Iron is a trace mineral necessary for making haemoglobin which is vital for oxygen delivery to all of the body. It is essential for healthy functioning of all organs, for muscle health and energy production, red blood cell health, immune function, brain health, hormone production and formation of connective tissue.
Low iron can cause symptoms of:
shortness of breath
fatigue
cognitive dysfunction
headache
dizziness and lightheadedness
cold hands and feet
pale skin
pain
heavier menstrual bleeding
Iron Studies - what are we looking at?
When assessing your iron levels or diagnosing an iron deficiency, there are some important characters of the story to be aware of:
Iron — reflects iron in red blood cells, circulating in your blood. Does not reflect how much iron your tissues are able to use
Ferritin — a collection of proteins that store iron and reflects intracellular iron, but can also reflect excess iron. It’s important to note that ferritin is an ‘acute phase reactant’ and will hold onto more iron in cases of infection and inflammation. As such, ferritin should always be tested alongside highly sensitive C-Reactive Protein, a marker of inflammation, listed below.
Transferrin — a transporter protein that shuttles iron throughout the body. Transferrin reflects iron ‘hunger’, if transferrin is high, it’s more indicative of iron deficiency.
Transferrin Saturation — a ratio of the of amount of iron to transferrin. Reflects how ‘full’ of iron your transferrin is.
We also recommend looking at:
Haemoglobin (Hb) — 65% of your body’s iron is stored as haemoglobin
MCV, MCH, MCHC & RDW — important red blood cell markers that you will see on a Full Blood Count (FBC) that can add further evidence if there is true iron deficiency or any degree of anaemia
B12 & Folate
hsCRP — inflammatory marker that is important to assess alongside iron studies, given how much of a role inflammation plays in iron metabolism
It’s ideal that your blood is drawn for analysis in a fasted state (between 8-12 hours of fasting from food), not after intense exercise or stress, and not during any active infection.
Now let’s dive into the longer story: iron metabolism
Essentially, iron is very easily toxic to the body, so your body doesn’t like to receive a lot of it at once. The only way we lose iron is blood loss, or if pathogenic bacteria, viruses or fungi are ‘stealing’ it, so it’s very easily stored.
The main form of stored iron is called ferritin, and is stored in our liver. Iron is also found in haemoglobin, attached to our red blood cells, in our muscles, and a small portion is unbound and circulating in our blood. Factors like inflammation, viruses or bacterial imbalances in the digestive tract will block or limit iron absorption AND/OR deplete ferritin stores, and this is why many people are iron deficient.
A main character in the iron story is a hormone called hepcidin. This hormone is produced by your liver and is a key regulator of iron metabolism. Hepcidin is a gate-keeper when it comes to iron being absorbed from your digestive tract (from food or supplementation) into your cells. When your body is trying to limit iron absorption, hepcidin is most active and keeping the ‘gates’ on your gut cells that receive iron CLOSED. And hepcidin has a low threshold for how much iron is too much: anything more than 24mg iron within 48 hours is too much.
If you’re taking an iron supplement, I invite you to grab the bottle now and check how much ‘elemental iron’ is listed on the ingredients. Are you surprised?
Excessive iron is not only a waste of supplementation (and money), but can potentially damage gut cells, create oxidative stress and trigger more inflammation. This creates a cycle of low iron, as your body can’t absorb it due to the inflammation, even though you keep taking an iron supplement!
Other reasons hepcidin might be high (therefore reducing iron absorption) include: inflammation, infection or chronic disease states. The aim of hepcidin here is well-intended: to reduce the availability of free iron to harmful bacteria, and to limit how much free iron is circulating (remember, because too much can create inflammation and oxidative stress. In an already inflamed or infected state, your body is trying to avoid more damage.)
When your body needs iron, hepcidin reduces. Less hepcidin means those ‘gates’ on your gut cells that iron can get across are more open and willing to receive iron. Hepcidin levels will generally be lower in states of frank iron deficiency, hypoxia (lacking oxygen) or anaemia due to significant blood loss.
To summarise:
High iron intake / low need for iron = high hepcidin, iron absorption reduced
Low iron intake / high need for iron = low hepcidin, iron absorption enhanced
Other factors that compromise iron absorption
Binders & Competitors
Other minerals and plants compounds can either bind to iron, preventing its absorption, or compete for the same ‘gates’ on our gut cells, reducing the chances of iron getting through those gates. These include:
Calcium
Manganese
Soy protein
Polyphenols
Phytates
Coffee
Black or green tea, including matcha
Iron forms & dosage
Not all forms of iron are absorbed the same.
Regarding supplementation, recommended forms are:
Iron bisglycinate
Iron amino acid chelate
Ferrous fumerate
Generally, we don’t recommend iron as ferrous sulphate.
Supplementation of iron may be problematic where dietary intake of iron rich foods is sufficient, whether animal-based (heme iron) or plant-based (non-heme iron), meeting the daily RDI of 27 mg of elemental iron per day.
In a healthy person, only around half of this target (14 mg) is absorbed from dietary sources, with the remainder being recycled from red blood cells by macrophages. Total daily absorption peaks at approx. 2-5 mg via healthy small intestines.
I’m vegetarian or vegan — what does that mean for me?
In a healthy diet it is an abundant mineral in animal and plant food sources, in both heme and non-heme forms. Whilst animal foods provide the most readily available form, non-heme forms via leafy greens provide a more abundant sources and in a well-balanced vegetarian or vegan diet, iron stores are not necessarily negatively impacted. Again, it’s more often inflammation or an activated immune system that is the root of low iron or ferritin levels, rather than not getting enough through the diet.
That said, we do recommend an honest and thorough analysis of your daily diet, with a nutritionist or naturopath, to ensure there is actually enough iron-rich foods sources present, with minimal competing compounds.
So, what’s triggering your iron deficiency?
Sources of blood loss
Bleeding anywhere along your gastro-intestinal tract
Bleeding haemorrhoids or fissures
Chronic menorrhagia (heavy periods) — normal menstruation does not cause iron deficiency. Signs of a heavy period include a bleed longer than 7 days, overnight ‘flooding’, changing a pad/tampon more frequently than every 2 hours for 2-3 days or >80mL of blood (if you’re able to measure with a menstrual cup).
Recent birth delivery
Lactation without sufficient repletion of nutrients
Multiple blood donations
Recent surgery
Decreased absorption of iron due to:
Celiac Disease
Inflammatory Bowel Diseases — Crohn’s and/or Ulcerative Colitis
Gastric bypass surgery
Gastritis related to autoimmunity or H. Pylori infection
Inflammation
Immune activation due to bacterial, viral or fungal infection
Excess intake of compounds that compete with or bind to iron, preventing its absorption, within 2 hours of iron supplementation or an iron-rich meal
Inadequate dietary iron intake (less than 27mg per day)
Here are my general recommendations for boosting iron levels:
Take an iron supplement, with 24mg of elemental iron or less, only every 2nd day.
By skipping a day, you’re allowing your hepcidin levels to reduce, so your gut is actually ready to absorb more. Taking it daily can only cause more inflammation and potential intestinal damage.
Iron is best absorbed in the morning, before eating, with some Vitamin C.
So taking your supplement before breakfast with a glass of fruit juice or a piece of fruit is ideal
To enhance absorption of iron from your diet, we recommend the use of a specific probiotic strain called Lactobacillus plantarum (299 V).
If not supplementing with iron, we recommend having an iron rich breakfast with a good source of Vitamin C and avoid those iron binders/competitors listed above within 30 minutes of your meal (or 2 hours if actively working to increase your iron stores)
For example: Shakshuka eggs with a free-range minced meat of your choice, tomatoes and a handful of sauteed leafy greens.
Deeper dives into iron
This blog so far, while a little complex, is only a summary of iron’s nuance. Over on The Nuanced Naturopaths Podcast, Julie and I have recorded 4 episodes dedicated to demystifying iron, going into more depth on various aspects of iron.
These episodes are some of our most played, most referenced and the ones we seem to send to patients and friends, time and time again. We wanted to condense our iron knowledge into one handy dandy page for easy digesting (and so we can stop bombarding our patients with multiple links!).
All About Iron & Our Holistic Take on Iron
Iron is one heck of a nuanced topic. Especially when it comes to iron deficiency. It's not as simple as grabbing an iron supplement from the chemist or getting an iron infusion, et voila, iron deficiency cured! There is a cause behind your iron deficiency, and there is a very nuanced way to treat it. Tune into our naturopathic breakdown on everything iron.
Interpreting Iron Studies, Diagnosing Deficiency & Iron Infusions
Delving into the nuance of iron infusions and going through the key players when interpreting your iron results on a blood test. Are iron infusions good or bad? Is there a grey area? Is iron deficiency even being diagnosed well? What does copper have to do with iron? We cover all this & more in this episode.
We Get Another Naturopath to Help Us Decode Iron’s Mysteries!
Laura Taylor, Naturopath and self-confessed science-nerd, dives into the nuance of decoding iron metabolism. What most health professionals are taught in their degrees does not generally reflect the latest understandings of iron markers and what they represent. Laura has dived down ALL the rabbit-holes, and uses her natural talent for explaining the complex in easily understood terms. Buckle in for a ride, and learn how to more accurately interpret what is going on with iron - it might challenge your understanding, but will almost certainly broaden it.
Iron in Pregnancy: How Iron Metabolism Changes in the 3rd Trimester & Why 'Normal' Reference Ranges Don't Apply to Pregnancy
Julie & I both hit the same wall at around the same time regarding the fear instilled into pregnant women about their problematic iron levels. In clinic and in life, we hear stories of women getting pressured into iron infusions, heavy supplementation or convinced they need extra interventions at the time of birth due to their appalling iron levels. There’s a pattern and a problem here, though: iron metabolism changes throughout pregnancy, especially in the 2nd and 3rd trimesters. Go figure, growing a human changes the perspective on some things! And there’s currently no universal reference ranges that doctors, OB/GYNs use to interpret iron studies accurately for this very specific population.
