Iron

Required for red blood cell production — only supplement when deficiency is confirmed

Anaemia Energy Oxygen Transport Cognition

Evidence strength:

Very strong — for confirmed deficiency; not for routine supplementation

Overview

Iron is an essential mineral and the central component of haemoglobin, the protein in red blood cells that carries oxygen from the lungs to every tissue in the body. It is also required for myoglobin (oxygen storage in muscle), energy production, and immune function.

Unlike most supplements on this wiki, iron is one where supplementation without a confirmed diagnosis of deficiency is not recommended — and may be harmful. The body has limited mechanisms to excrete excess iron, which can accumulate and cause oxidative damage. For this reason, blood testing before and during iron supplementation is essential.

Seniors: an important distinction Iron-deficiency anaemia in older adults is most commonly caused by chronic blood loss (particularly from the gastrointestinal tract) or malabsorption — not simply inadequate dietary intake. A new diagnosis of iron deficiency in an older adult should always prompt investigation for an underlying cause before supplementation begins.

What the Evidence Shows

Iron-deficiency anaemia

Iron supplementation is the definitive treatment for iron-deficiency anaemia. It reliably raises haemoglobin and ferritin levels, resolves symptoms (fatigue, breathlessness, pallor, cold intolerance), and improves quality of life. The response is usually seen within 4–8 weeks.

Cognitive function and fatigue

Iron is required for dopamine synthesis and neurological function. In individuals with iron deficiency (even without overt anaemia), supplementation improves attention, processing speed, and energy. These benefits are not seen in those with normal iron stores.

Exercise capacity

Iron deficiency significantly impairs aerobic capacity and exercise tolerance, even in the absence of frank anaemia. Correction of iron status improves VO2max and exercise performance in athletes and in older adults who are deficient.

Chronic disease anaemia

Many older adults have anaemia of chronic disease — a different mechanism from iron deficiency. In this case, iron supplements are typically not effective and may be harmful. Accurate diagnosis distinguishing the two types of anaemia is essential before treatment.

Dosage by Age Group

Group	Recommended / Treatment Dose	Notes
Men 19+	8 mg/day (RDA)	Usually met by diet if consuming red meat or fortified foods
Women 19–50	18 mg/day (RDA)	Higher requirement due to menstrual losses
Women 51+ (post-menopausal)	8 mg/day (RDA)	Needs drop substantially after menopause
Treating iron-deficiency anaemia	100–200 mg elemental iron/day	Under medical supervision; ferrous sulphate, gluconate, or fumarate
Tolerable upper limit	45 mg/day	From supplements; do not exceed without medical supervision

Every-other-day dosing (e.g., 100 mg on alternate days) has been shown in some studies to improve absorption and reduce side effects compared to daily dosing, due to hepcidin regulation.

Australian brands

What to buy

Iron is available as tablets, capsules, and liquid. For seniors, liquid iron (e.g., Floradix or Spatone sachets) is gentler on the stomach than high-dose tablets. Standard tablets (ferrous sulfate or ferrous gluconate) are used for treating confirmed deficiency. Always confirm iron deficiency with a blood test before supplementing — excess iron is harmful.

Brand	Form	Typical product	Approx. cost
Ferro-Grad C (Abbott)	Tablet (controlled-release)	Ferrous sulfate 325 mg + Vitamin C (30 tabs)	$12–16
Blackmores	Tablet	Iron Chelate 24 mg elemental iron (30 tabs)	$12–16
Floradix (Salus)	Liquid	Iron + Herbs liquid (250 ml, ~7.5 mg elemental iron/10 ml)	$28–36
Spatone	Liquid sachet	Natural iron-rich water sachets (28 sachets, ~5 mg/sachet)	$22–28
Herbs of Gold	Capsule	Iron 24 mg (iron glycinate chelate, 60 caps)	$20–26

Prices are approximate retail (Chemist Warehouse, Priceline, health food stores). For seniors with mild-to-moderate deficiency, gentle liquid forms (Floradix, Spatone) or chelated capsules (Herbs of Gold) are better tolerated and cause less constipation than ferrous sulfate tablets. Ferro-Grad C is a long-standing pharmacy product for treating confirmed anaemia under medical guidance.

Safety & Cautions

Important cautions Iron supplements commonly cause gastrointestinal side effects including nausea, constipation, and dark stools. Taking iron with food reduces side effects but also reduces absorption. Vitamin C taken simultaneously improves absorption. Iron overdose is dangerous and can be fatal — store supplements securely away from children.

Drug interactions Iron significantly reduces absorption of many drugs including levothyroxine (thyroid hormone), fluoroquinolone antibiotics, tetracyclines, bisphosphonates, levodopa, and methyldopa. Take iron at least 2–4 hours away from these medications. Calcium and antacids reduce iron absorption.

Synergistic Combinations

Iron + Vitamin C: Ascorbic acid (vitamin C) converts ferric iron to the more absorbable ferrous form and significantly improves non-haem iron absorption. Taking iron with a glass of orange juice or a vitamin C supplement at the same time is strongly recommended.
Iron + Vitamin B12 + Folate: All three are required for healthy red blood cell production. When anaemia is present, all three should be assessed. Combined deficiency is common in older adults and those with malabsorption.

Avoid combining iron with: Calcium, zinc, and magnesium all compete with iron for absorption. Take iron and these minerals at different times of day.

📚 Key Scientific References

1.Goddard AF et al. Guidelines for the management of iron deficiency anaemia. Gut. 2011;60(10):1309–1316 — updated by: Camaschella C. Iron-Deficiency Anemia. N Engl J Med. 2015;372(19):1832–1843, PMID 25946282

Authoritative clinical review establishing iron deficiency anaemia diagnosis and treatment principles, including the importance of investigating the underlying cause in older adults.
2.Favrat B et al. Systematic review and meta-analysis: what is the evidence for oral iron supplementation in treating anaemia in elderly people? Cochrane Database Syst Rev — summarised in: Age Ageing. 2015;44(3):372–378, PMID 25644019

Systematic review finding oral iron raises haemoglobin by 0.35 g/dL per week in elderly patients with iron deficiency anaemia, with consistent evidence across trials.
3.Moretti D et al. Oral iron supplements increase hepcidin and decrease iron absorption from daily or twice-daily doses in iron-depleted young women. Blood. 2015;126(17):1981–1989, PMID 26289639

RCT establishing the physiological basis for alternate-day dosing: iron taken on alternate days achieves better absorption by avoiding hepcidin upregulation from daily doses.
4.Bloor SR et al. Management of iron deficiency in children, adults, and pregnant individuals: evidence-based and expert consensus recommendations. Lancet Haematol. 2025;12(4):e290–e302, doi:10.1016/S2352-3026(25)00038-9

Current 2025 evidence-based guidelines recommending IV iron as preferred route in frail older adults and those with GI intolerance to oral supplementation.
5.Houston BL et al. Efficacy of iron supplementation on fatigue and physical capacity in non-anaemic iron-deficient adults: a systematic review of randomised controlled trials. BMJ Open. 2018;8(4):e019240, PMID 29654016

Systematic review showing iron supplementation improves fatigue and exercise tolerance even in non-anaemic individuals with confirmed iron deficiency.