Why "Optimum" Is Not the Same as "Normal" When Measuring Iron Levels in Women

Iron is a critical mineral for overall health, particularly for women who experience menstruation, pregnancy, or other factors that can deplete iron stores. However, there is a key distinction between “normal” iron levels and “optimal” iron levels. While many women are told their iron levels fall within the normal range, they may still experience symptoms of deficiency. This article explores why normal isn’t always enough, what optimal levels look like, symptoms of low iron, and how to restore iron levels effectively through supplementation.

Understanding Iron Levels: Normal vs. Optimal

Iron levels are typically measured using ferritin, which reflects stored iron in the body. The standard laboratory reference range for ferritin varies but often falls between 15-150 ng/mL for women. These reference ranges only highlight those patients that are SEVERELY deficient. However, many functional medicine practitioners and iron experts suggest that optimal ferritin levels should be between 70-100 ng/mL for optimal energy, cognitive function, and overall well-being. The National Institute of Clinical excellence states that “In all people, a serum ferritin level of less than 30 micrograms/L confirms a diagnosis of iron deficiency.”

A woman with a ferritin level of 20 ng/mL may be considered “normal” by lab standards, but she may experience significant fatigue, hair thinning, and brain fog. Conversely, at an optimal level of 80 ng/mL, she is more likely to feel energized and healthy.

Symptoms of Low Iron in Women

Even if iron levels are technically “within range,” they may not be sufficient to support bodily functions. Symptoms of low iron can include:

• Fatigue and weakness – Persistent tiredness that doesn’t improve with rest
• Hair thinning or loss – Reduced oxygen supply to hair follicles weakens growth and triggers telogen effluvium a disorder of excessive hair shedding.
• Pale skin – A visible sign of decreased red blood cell production
• Shortness of breath – Reduced oxygen transport affects breathing (4 molecules of iron are required to make one molecule of haemoglobin).
• Dizziness or headaches – The brain requires adequate oxygenation.
• Cold hands and feet – Poor circulation from low iron levels
• Restless legs syndrome – A common neurological symptom of iron deficiency which is as yet unexplained.
• Heart palpitations – The heart compensates for reduced oxygen-carrying capacity by increasing the rate at which it beats which maintains tissue oxygen delivery.

How to Achieve Optimal Iron Levels

1. Dietary Iron Intake

Iron can be obtained from food sources such as:

• Heme iron (more bioavailable) – Found in red meat, liver, and poultry
• Non-heme iron (less bioavailable) – Found in spinach, beans, and fortified cereals
• Pairing non-heme iron with vitamin C-rich foods (like citrus fruits) enhances absorption, while consuming iron with calcium or tannins (in tea and coffee) can inhibit absorption.

2. Oral Iron Supplementation

For mild to moderate iron deficiency, oral iron supplements can be effective. Common forms include:

• Ferrous sulfate (most common but can cause gastrointestinal issues)
• Ferrous bisglycinate (gentler on the stomach)
• Heme iron polypeptide (more absorbable but expensive)

Oral iron should be taken on an empty stomach or with vitamin C for better absorption. However, some women experience constipation, nausea, or stomach pain with oral iron, making adherence difficult.

3. Intravenous (IV) Iron Infusions

For women with severe iron deficiency, oral iron may not be enough. IV iron infusions can rapidly restore iron stores, bypassing the digestive tract. IV iron is often recommended for women with:

• Severe anemia (Hb < 10 g/dL and ferritin < 30 ng/mL)
• Poor tolerance to oral iron
• Malabsorption conditions (e.g., celiac disease, Crohn’s disease)
• Heavy menstrual bleeding leading to chronic depletion

Iron is also administered to patients when the symptoms they experience due to its deficiency are considered by the patient unacceptable to continue to put up with.

Why Are Reference Ranges Not Higher?

• Risk of Iron Overload: Historically, doctors have been cautious about raising ferritin reference ranges due to the risk of iron overload conditions like hemochromatosis, where excessive iron can lead to organ damage. HOWEVER, At Effect Doctors we proactively test for iron levels and monitor the response to any infusion very closely, ensuring safe and effective iron replacement.
• Focus on Severe Deficiency: Traditional guidelines have focused on preventing severe iron deficiency anemia, rather than optimizing iron levels for best performance and well-being. At Effect Doctors we take a holistic proactive approach to optimising health.
• Variation Between Labs and Countries: European, Japanese and US doctors are much less reluctant to administer IV iron to patients than UK Doctors. In part this is due to the policies of our state funded healthcare system, NICE guidelines limit iron infusions to only the most critically deficient iron deficiency anaemia patients. It is a decision driven by cost rather than clinical outcome

The 15 µg/L lower limit is largely based on preventing severe iron depletion, rather than ensuring optimal iron levels. Many experts argue that ferritin should be maintained at least above 50-70 µg/L for good health, with some advocating for 100-150 µg/L in symptomatic individuals. However, reference ranges remain lower due to historical precedent and concerns about iron overload.

Expert Help from Effect Doctors

Effect Doctors specialize in assessing iron levels and providing tailored treatments to restore optimal iron status. They use advanced testing to determine precise deficiencies and offer expert guidance on supplementation. For those struggling with low iron levels, they provide IV iron infusions, which can be a faster and more effective solution than oral supplements. Their medical team ensures that iron is administered safely, helping patients regain energy and overall well-being efficiently.
IV iron is administered in a clinical setting and provides faster relief from symptoms, typically within a few weeks.

Conclusion

The standard definition of “normal” iron levels does not necessarily equate to optimal health. While a ferritin level above 15 ng/mL may be classified as normal, most patients feel significantly better with levels between 70-100 ng/mL. Understanding the symptoms of iron deficiency and knowing how to effectively supplement through diet, oral iron, or IV infusions can help women achieve optimal well-being. If you suspect low iron, consult a healthcare provider to assess your levels and determine the best approach to replenishing your iron stores.

References

World Health Organization. (2021). Iron Deficiency Anaemia. Retrieved from https://www.who.int/health-topics/anaemia

American Society of Hematology. (2022). Understanding Iron Levels and Deficiency. Retrieved from https://www.hematology.org

Mayo Clinic. (2023). Iron deficiency anemia – Symptoms and causes. Retrieved from https://www.mayoclinic.org