Micronutrient of the Week: Iron

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Micronutrient of the Week: Iron

Iron is often misunderstood in modern nutrition, yet it is essential for oxygen delivery, energy production, thyroid function, immune resilience and cognitive health, sitting at a delicate balance between deficiency and excess. Too little iron compromises vitality, while poorly managed supplementation can contribute to oxidative stress, gut disturbance and microbial imbalance.

For an overview of micronutrients and nutrient density, refer to our previous article on magnesium which outlines the foundational principles that apply across this micronutrient series.

Iron’s role in the body

Iron’s primary role is oxygen transport. It forms the core of haemoglobin in red blood cells, enabling oxygen delivery from the lungs to tissues and organs. When iron availability is compromised, cells rely on less efficient energy pathways, often presenting as fatigue, reduced exercise tolerance and impaired cognitive performance.

Iron also supports:

• Mitochondrial energy production
• Thyroid hormone conversion
• Neurotransmitter synthesis
• Immune function and infection resistance
• Muscle performance and recovery
• Growth and development during pregnancy and childhood

Adequate iron status underpins both physical stamina and mental clarity. Iron utilisation is also influenced by gut health, nutrient density and digestive efficiency, highlighting the importance of a holistic, food-first approach.

Why iron deficiency is so common

Iron deficiency remains one of the most prevalent nutrient deficiencies, particularly among women of reproductive age. Key contributors include:

Increased physiological demand
Pregnancy, breastfeeding, menstruation, adolescence, endurance exercise and growth phases all increase iron requirements.

Reduced absorption
Low stomach acid, gut inflammation, coeliac disease, IBS and long-term use of antacids or proton pump inhibitors impair iron absorption.

Dietary patterns
While vegetarian diets may support iron status for some people, the lower bioavailability of non-haem iron and its sensitivity to inhibitors can make maintaining adequate stores challenging without careful planning.

Blood loss
Heavy menstrual bleeding, frequent blood donation or occult gastrointestinal blood loss can significantly deplete iron stores.

Iron depletion often develops slowly and may go unnoticed until reserves are low.

Common signs of low iron

Symptoms are nonspecific and frequently attributed to stress, poor sleep or hormonal changes:

• Persistent fatigue or low stamina
• Brain fog or reduced concentration
• Shortness of breath with mild exertion
• Cold hands and feet
• Hair shedding or brittle nails
• Restless legs
• Dizziness or light-headedness

Fatigue does not automatically indicate iron deficiency. Thyroid dysfunction, blood sugar instability, sleep disruption, infection, inflammation and chronic stress can all present with similar symptoms. This is why testing and clinical context are essential.

Ferritin and iron storage

Ferritin reflects stored iron and provides insight into the body’s reserve supply. It is common to see haemoglobin and serum iron within pathology ranges while ferritin sits at the lower end, indicating depleted stores. In this state, the body maintains short-term oxygen delivery by drawing down reserves, often before anaemia develops. Low ferritin is frequently associated with fatigue, hair shedding, reduced exercise tolerance and impaired stress resilience, particularly in menstruating women and during the postpartum period.

A note on pathology ranges

Pathology reference ranges are broad and designed to detect disease rather than support optimal function. Clinically, many people experience symptoms when results sit at the low or high extremes of a reference range, despite being labelled “normal.” From a functional and naturopathic perspective, markers are generally most supportive of wellbeing when they sit closer to the middle of a range, which can serve as a useful starting point. Functional ranges, however, are often narrower, and depending on the specific marker and individual context, it may be preferable to aim slightly higher or lower than the midpoint. Results should always be interpreted alongside symptoms, inflammatory markers and life stage.

Ferritin also functions as an acute phase reactant and may be artificially elevated during infection or inflammation, masking underlying deficiency. Functional practitioners may also assess transferrin saturation and inflammation markers to get a more complete picture of iron status.

Iron-rich foods, absorption enhancers and inhibitors

Iron intake is only one part of the picture. Absorption is shaped by food form, preparation, digestive capacity and nutrient interactions.

Key food sources

Note on liver
Liver is one of the most concentrated food sources of bioavailable iron, along with vitamin A, B12, folate and copper, all of which support iron utilisation. For those who do not enjoy the taste, liver can be incorporated in several practical ways: mixed mince including offal, frozen and grated into meals, or high-quality dehydrated liver powders in food or capsules. Liver powder can be mixed into scrambled eggs, bolognese, curries or soups, allowing access to nutritional benefits without eating whole liver.

Factors that enhance absorption

Tip: Grains, legumes, nuts and seeds naturally contain phytates that bind minerals and reduce absorption. Soaking, sprouting or fermenting these foods before cooking improves iron bioavailability.

Factors that inhibit absorption

Calcium-rich desserts such as yoghurt or ice cream are best avoided immediately after iron-dense meals.

Digestion and nervous system state

Adequate stomach acid is required to release iron from food and supplements. Eating in a calm, parasympathetic state supports gastric acid secretion and enzyme activity. Chronic stress, rushed meals and eating on the go impair mineral absorption. Supporting digestion and nervous system regulation often improves iron status more effectively than increasing intake alone.

Iron supplementation in clinical practice

In Australian hospital and primary care settings, including antenatal and postpartum care, ferrous sulfate is commonly prescribed, with iron polymaltose sometimes used as an alternative when tolerance is an issue. Both forms tend to prioritise short-term correction of haemoglobin rather than meaningful restoration of iron stores, and may be inefficient for rebuilding ferritin if absorption, inflammation or ongoing losses are not addressed. Ferrous sulfate is frequently associated with constipation, nausea, abdominal discomfort and poor tolerance, while polymaltose may be mildly gentler on the gastrointestinal tract but slower and less efficient for repleting ferritin.

Iron bisglycinate, a chelated form, is generally better absorbed and gentler on the gastrointestinal tract. Improved tolerance often translates to better adherence and more consistent repletion. Quality formulas may combine bisglycinate with cofactors such as vitamin C, B12, folate and copper to support absorption, transport and utilisation.

General guidance for supplementation:

Avoid taking iron alongside:

• Calcium, magnesium or zinc supplements
• Multimineral formulas
• Antacids or reflux medications
• Tea, coffee or cocoa

Functional practitioners often individualise dosing based on ferritin, inflammation markers, gut function and ongoing losses, rather than haemoglobin alone.

The takeaway

Iron is foundational to energy, cognition and resilience, but it requires nuance. Focusing on a food-first approach that supports digestion, optimises absorption, and considers individual physiology offers the most sustainable path to restoring iron balance. Rather than assuming fatigue automatically signals iron deficiency, the aim is to understand what the body truly needs and respond with a holistic approach that promotes root healing and long-term wellbeing.

If there is a specific micronutrient you would like us to explore in future articles, we welcome your suggestions and feedback in the comments.

Disclaimer

This article is for general educational purposes only and does not replace personalised medical or nutritional advice. Individual iron requirements vary depending on health status, life stage and genetic factors. Consult a qualified healthcare practitioner before supplementing, particularly during pregnancy, breastfeeding or when managing a medical condition.

Reference List

1.   Clinical Naturopathic Medicine (2nd ed.) — Leah Hechtman, Elsevier Australia.

2.   Hallberg L & Hulthén L. Iron absorption from ferrous bisglycinate and ferrous sulfate in meals. PubMed: 10837299.

3.   Zimmermann MB & Hurrell RF. Dietary iron absorption and regulation. NCBI Bookshelf: NBK540969.

4.   Sun B et al. (2024). Iron deficiency anemia: a critical review on iron absorption, supplementation and its influence on gut microbiota. RSC Pubs: D3FO04644C.

5.   Pasricha SR et al. The effects of oral ferrous bisglycinate supplementation on haemoglobin and ferritin concentrations. PubMed: 36728680.

6.   Verywell Health. What Is Chelated Iron? (online resource).

7.   ACS Omega. Iron Absorption: Factors, Limitations, and Improvement Methods.

8.   J Nanobiotechnology. Gut microbiome restoring biogenic ferritin mineral as an effective oral iron supplement.

9.   Verywell Health. Spinach and Iron Absorption.