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"Normal" blood results but still feeling tired? It could be your ferritin.
Have you been told your blood results are "normal" but you still feel exhausted, can't concentrate, or feel cold all the time? According to the new guidelines, you previous "normal" ferritin may now be classified as being deficient.
A few days ago the American Society of Hematology published their first ever iron deficiency guidelines. And they raised the ferritin cut off to diagnose iron deficiency, which means your previous "normal" ferritin may now be considered a deficiency.
What blood tests do we do to assess your iron?
When you get your iron tested, there are a few markers that doctors look at:
Iron: Iron is an essential mineral required for oxygen transport and cellular energy production. It forms the core of haemoglobin, the protein in red blood cells that binds oxygen in the lungs and delivers it to tissues throughout the body. Your iron levels measure the total amount of iron circulating in your blood.
Transferrin: Transferrin is the primary protein responsible for transporting iron safely through the bloodstream. Transferrin is essentially the body’s “iron courier service.” When there is an iron deficiency, transferrin levels typically increase. This happens because the liver ramps up production of this transport protein to pick up and transport as much iron as it can to deliver it to the cells that need it.
Transferrin saturation: If transferrin is like a bus and iron is like the passengers, transferrin saturation is the proportion of seats on the bus occupied by the iron passenger. In iron deficiency, we typically see a low transferrin saturation because there isn't enough iron to fill up all these transport proteins.
Ferritin: Ferritin is an iron storage protein, and reflects the body’s stored iron reserves. Think of ferritin as the body’s “iron storage tank.” It provides a longer-term view of iron status, helping to identify whether the body has sufficient reserves or is running low, even before typical symptoms.
The ASH recommends that iron deficiency is diagnosed based on ferritin levels for everyone except in people with inflammation, and we'll talk about why below.
How did we get our normal reference ranges?
Previously, an iron deficiency was diagnosed with a ferritin of <15 ng/mL. When reference ranges were first set, the process was essentially take a sample of seemingly healthy people, measure their ferritin, take two standard deviations below and above the average, and call that "normal". The problem is that this value was based on “apparently healthy individuals”, and people with an iron deficiency were not excluded from this. As a result, this has led to an under diagnosis of iron deficiency.
What are the new ferritin reference ranges?
They are:
Adults, excluding menstruating or pregnant women: ≤30 ng/mL.
Menstruating women: ≤30 ng/mL.
Women with heavy menstrual bleeding, abnormal uterine bleeding, ongoing symptoms of an iron deficiency or additional risk factors: ≤50 ng/mL.
Adults with symptoms of or risk factors for an iron deficiency, such as extreme exercise, those following a vegan or vegetarian diet, celiac disease, those who have had a gastric bypass, and other chronic medical conditions: ≤50 ng/mL.
Pregnant women: ≤30 ng/mL.
Pregnant women with anaemia: ≤50 ng/mL.
Adults with any inflammation (for example, due to an infection, cancer, inflammatory bowel disease, chronic kidney disease, etc.): ≤100 ng/mL BUT in this case, a transferrin saturation of <20% is recommended to diagnose iron deficiency.
Why is the recommended ferritin level different for people with inflammation?
Ferritin acts as what we call an acute-phase reactant, which means it increases in the presence of inflammation. This is why iron deficiency is diagnosed at a higher level in these individuals, because their "normal" ferritin is higher than someone without inflammation, and we look at the transferrin saturation.
What are the symptoms of an iron deficiency?
Fatigue
Dizziness
Headaches
Reduced exercise tolerance
Heart palpitations
Feeling cold all the time
Pica (or cravings for non-food items such as dirt)
Hair loss or thinning
Thin or brittle nails
Why are athletes at higher risk of an iron deficiency?
Athletes have higher demands than less active individuals. Training expands blood volume and creates more red blood cells, which raises the body's baseline need for iron in order to produce these red blood cells. Then there have also been additional theories explaining increased iron losses in athletes due to:
Gastrointestinal haemorrhages: Prolonged, intense endurance efforts may cause minor microdamage and bleeding in the digestive tract.
Foot strike haemolysis: Running and high-impact strides cause red blood cells to break down as feet repeatedly strike hard surfaces.
Inadequate dietary intake: Restrictive eating patterns or low consumption of iron relative to needs may result in insufficient dietary iron.
Iron loss due to heavy sweating: Heavy sweating causes some iron loss which can compound over time with multiple intense sessions per week.
Increased hepcidin production: Intense exercise triggers a temporary rise in a hormone called hepcidin. This reduces how much iron your gut absorbs from food and how much iron gets released from your body's stores, for about a day following a hard workout.
What symptoms should athletes be aware of?
Persistent, unusual fatigue that is out of keeping with training volume.
Declining performance despite consistent or even reduced training.
Experiencing longer time to recover after workouts.
Shortness of breath during efforts that used to feel normal or easier.
Who should get their iron tested?
Athletes wanting to optimise their performance.
Women experiencing heavy periods or abnormal bleeding.
Anyone with the symptoms of an iron deficiency.
Anyone with an inflammatory condition as mentioned above.
Test. Don't guess.
Want to get your iron and ferritin levels tested?
You can book an appointment through the link below or reply to this email.
Either in-person in Vredehoek, Cape Town or online through Zoom.
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