Iron

Iron is an essential mineral that helps your body create haemoglobin — the oxygen-carrying protein inside red blood cells. Haemoglobin is a delivery system: it picks up oxygen from your lungs and delivers it to tissues throughout your body, including your muscles and brain. Without enough iron, your body cannot make healthy red blood cells in adequate quantities, and this directly reduces how much oxygen your cells receive. This is why low iron affects energy, thinking, physical stamina, and even mood.

Iron also supports many other biological processes. It plays a key role in brain development, neurotransmitter production, immune function, and the creation of enzymes that help your body make energy. Because iron is used constantly, the body must carefully regulate how much it absorbs, stores, and uses. You absorb iron through food, but absorption varies depending on digestive health, stomach acid levels, and whether the iron comes from animal sources (which absorb easily) or plant sources (which require more steps to convert into usable forms). Your body stores iron as ferritin, a protein that acts as a reserve supply. When you need more iron — during exercise, growth spurts, pregnancy, recovery from illness, or blood loss — ferritin releases iron to help maintain healthy red blood cell production.

Iron levels must stay in a healthy balance: too little leads to deficiency and reduced oxygen delivery, while too much can accumulate and harm organs. Understanding your iron result helps you take clear, targeted steps to support oxygen transport, energy production, and long-term health.

Iron matters because oxygen is essential for nearly every function in the human body. When iron stores are low, your tissues — including your muscles, brain, and heart — receive less oxygen. This creates a ripple effect of symptoms: fatigue, difficulty concentrating, dizziness, headaches, shortness of breath, reduced exercise capacity, cold intolerance, hair shedding, and restless legs. Low iron can also weaken the immune system and impair cognitive performance. These symptoms often develop slowly, which means low iron may go unnoticed until levels have dropped significantly.

Iron deficiency is one of the most common nutrient deficiencies worldwide. It is most often caused by blood loss (such as heavy menstrual bleeding or gastrointestinal bleeding), low intake of iron-rich foods, or trouble absorbing iron due to digestive issues, inflammation, or medications like antacids or NSAIDs. Children, menstruating women, pregnant people, and athletes have higher iron needs and are therefore at increased risk. Untreated iron deficiency can progress to iron deficiency anaemia, where both iron and haemoglobin are low, significantly affecting stamina, mood, and daily function.

High iron also matters but for different reasons. Excess iron can accumulate in tissues and create oxidative stress, contributing to joint pain, abdominal discomfort, liver injury, hormonal disturbances, and metabolic issues such as diabetes. High iron is sometimes caused by genetic conditions like hereditary haemochromatosis but may also appear due to repeated transfusions, iron overload from supplements, or chronic inflammation and liver stress. Because inflammation raises ferritin — the main storage form of iron — even without true iron overload, high iron levels must always be interpreted in context.

Optimal iron status supports healthy pregnancy, effective training and exercise recovery, mental clarity, stable immune function, and overall vitality. Monitoring iron — and related markers such as ferritin, transferrin saturation, haemoglobin, and CRP — helps identify whether symptoms are due to deficiency, overload, or an underlying condition like inflammation or digestive problems. Maintaining iron in the optimal range ensures the body can produce enough oxygen-carrying red blood cells and maintain energy, resilience, and long-term metabolic health.

Dietary factors

Iron levels depend heavily on intake and absorption.

• Lower iron may result from inadequate intake of iron-rich foods such as red meat, chicken thighs, eggs, beans, lentils, and spinach. Intake may be adequate but poorly absorbed when meals include coffee, tea, excess calcium, or phytates from grains and legumes. Low vitamin C at meals also reduces absorption.

• Higher iron may occur if someone consumes high amounts of red meat or takes iron supplements when they are not needed.

Lifestyle factors

Heavy menstrual cycles, regular endurance exercise, pregnancy, breastfeeding, and frequent blood donation may lower iron. Chronic alcohol intake or liver stress can raise ferritin levels and make iron appear high even without true excess.

Related biomarkers

Ferritin reflects iron stores, while hemoglobin measures oxygen-carrying capacity. Transferrin saturation shows how much iron is circulating and available for use. CRP and other inflammation markers help determine whether elevated ferritin is due to inflammation rather than excess iron.

Micronutrient impacts

Vitamin C enhances iron absorption, while low vitamin B12 or folate may contribute to anemia even when iron intake is sufficient. Excessive zinc intake can reduce iron absorption. Digestive conditions like celiac disease impair overall nutrient absorption.

Environmental or medical factors

NSAIDs and aspirin may cause gastrointestinal bleeding, reducing iron. Antacids and proton pump inhibitors reduce stomach acid and impair absorption. Inflammation, infection, pregnancy, and rapid growth phases in children raise iron requirements. Liver conditions or transfusions may elevate iron.

If your iron is low:

• Eat heme-iron foods (beef, lamb, liver, sardines, mussels, chicken thighs).

• Combine plant-based sources (lentils, beans, tofu, spinach) with vitamin C foods (capsicum, citrus, strawberries) to enhance absorption.

• Avoid tea or coffee with meals; wait at least one hour before or after eating.

• Consider a gentle iron supplement (such as ferrous gluconate or iron bisglycinate) with vitamin C, under professional guidance.

• Check for underlying issues such as gut inflammation or heavy bleeding.
  

If your iron is high:

• Avoid high-dose supplements and iron-fortified foods unless prescribed.

• Reduce alcohol and processed food intake to support liver health.

• Prioritise antioxidant-rich foods (berries, cruciferous vegetables, turmeric, olive oil).

• Additional testing can help to identify the root cause. Analyse results together with ferritin and transferrin saturation with your primary care provider.

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