GO Iron 1-A-Day

Iron is one of the few things on our shelves where the honest answer starts with a blood test, so these are the questions our naturopaths ask in store before you buy a bottle.

A good fit if

• An iron study or ferritin test has shown your stores are low, and your doctor agrees you should top them up
• You're vegetarian or vegan, or eat little meat, and you've had your iron checked rather than guessing
• You have heavy periods and a low test result, and want a maintenance dose between check-ups
• A stronger iron product left you constipated or nauseous and you want a lower-dose option
• You want to understand elemental iron on a label before you compare products

Check with us first if

• You take levothyroxine. NIH notes that taking them together can noticeably reduce its effect, so you need to space them apart.
• You take a proton pump inhibitor. With less stomach acid, people on these often don't respond well to iron tablets.
• You take tetracycline or quinolone antibiotics, or levodopa. Iron binds to these in the gut and reduces how much you absorb.
• You're pregnant or breastfeeding. Your needs rise steeply, but your pregnancy care team should set the dose.
• You have coeliac disease or inflammatory bowel disease, or you've had stomach or bowel surgery. Absorption is affected and the cause needs looking into.
• You give blood regularly. Regular donation runs down your stores, so it's worth keeping an eye on.
• You take calcium supplements, or have tea, coffee or wine with meals. All of these reduce absorption, so spacing matters.
• You already take a multivitamin. Check whether it contains iron first.

• Ferrous sulfate. Best known for: The cheapest iron salt and the comparator used in most published trials. Absorption: 20 per cent elemental iron by weight, so 100 mg of the salt supplies about 20 mg of iron. Typical use: Tablets. Also the form the gastrointestinal side-effect evidence was built on, and the one people most often abandon.
• Ferrous fumarate. Best known for: The highest elemental yield of the common salts, so fewer milligrams of compound are needed. Absorption: 33 per cent elemental iron by weight. Typical use: Tablets and combination products, where tablet size matters.
• Ferrous gluconate. Best known for: Low elemental dose per unit of compound, which is why it appears in liquids. Absorption: 12 per cent elemental iron by weight. The lowest yield of the three classic salts. Typical use: Liquid iron tonics and lower-strength tablets, often taken in divided doses.
• Iron amino acid chelate. Best known for: The wording most often printed on Australian labels, where elemental iron is declared separately. Absorption: The Determination caps iron in the chelate at 25 per cent, so compound weight is several times the iron weight. Typical use: Modest elemental doses; presented as gentler, though head-to-head tolerability evidence is limited.
• Iron bisglycinate (ferrous bisglycinate). Best known for: A specific glycine chelate, listed in Schedule 1 in its own right rather than as generic chelate. Absorption: Two glycine molecules are proposed to shield the iron from inhibitors such as phytate; comparative human evidence is thinner than the marketing suggests. Typical use: Lower elemental doses, and the form most often chosen after a stronger salt was not tolerated.
• Iron polymaltose. Best known for: A non-ionic iron–carbohydrate complex rather than a simple salt, familiar from pharmacy brands. Absorption: Iron is held inside a polymaltose shell, so less free iron is released in the gut. Typical use: Not available in Australian listed complementary medicines. Absent from Schedule 1, so products containing it hold their own ARTG registrations.

Reference values. The NHMRC Nutrient Reference Values set the iron RDI at 8 mg a day for adult men of all ages, 18 mg a day for women aged 19–50 and 8 mg a day for women 51 and over. In pregnancy it's 27 mg a day, and 9–10 mg while breastfeeding. For younger ages: 9 mg (1–3 years), 10 mg (4–8), 8 mg (9–13), 11 mg for boys 14–18 and 15 mg for girls 14–18. The Adequate Intake for babies is 0.2 mg a day up to six months and 11 mg from seven to twelve months.

Typical supplemental range. Australian over-the-counter products stay under the 24 mg limit, and most single-ingredient tablets provide 5 mg to 24 mg of elemental (actual) iron. Liquid tonics are lower again per dose. Always compare the elemental iron figure, never the milligrams of the compound, because 24 mg of iron and a 24 mg tablet of an iron salt are not the same thing.

Upper level. The NHMRC Upper Level of Intake is 45 mg a day for adults, and much lower for children. Better Health Channel says that for children "20 mg per day is the safe upper limit", while noting "most iron supplements contain around 100 mg per tablet". That's why iron is a leading cause of accidental poisoning in children.

Worth knowing. Doses used to correct a diagnosed deficiency are above the over-the-counter limit and should be managed by your doctor. The number that tells you whether any of this applies to you is a ferritin result, not a milligram figure. What you need depends on your age, diet and health, so talk to one of our naturopaths.

Food first, where the diet allows it.

• Oysters, cooked: about 8 mg per 85 g serve: haem iron, the most readily absorbed
• Beef liver: about 5 mg per 85 g serve
• White beans, canned: about 8 mg per cup: non-haem, so pair with a vitamin C source
• Lentils, boiled: about 3 mg per half cup
• Tofu, firm: about 3 mg per half cup
• Broccoli: cooking changes the maths: about 6 per cent of the iron is absorbed from raw broccoli, against 30 per cent from cooked

This list is the part of the page we will not shorten. If any of it applies to you, talk to one of our naturopaths or your doctor before starting.

• Haemochromatosis and iron-overload conditions. Avoid; surplus iron cannot be excreted.
• Repeated blood transfusions. Avoid unless a specialist directs it.
• Children. Never without a doctor's direction; an overdose can cause death (Better Health Channel).
• Suspected iron ingestion by a child. Emergency; Poisons Information Centre 13 11 26.
• Self-treating tiredness without a blood test. Healthdirect: an iron study is the only reliable test.
• Levothyroxine. Simultaneous ingestion can clinically reduce its efficacy (NIH).
• Proton pump inhibitors. Less gastric acid, lower absorption, blunted response.
• Tetracycline and quinolone antibiotics, and levodopa. iron binds them in the gut.
• Calcium supplements, tea, coffee, wine and wholegrain phytates. All reduce absorption.
• Pregnancy and breastfeeding. The dose belongs to the antenatal team.
• Coeliac disease, inflammatory bowel disease, gastrointestinal surgery. Altered absorption; investigate the cause.
• Regular blood donors. Stores deplete; monitor them.
• Constipation, nausea, vomiting, diarrhoea and dark stools are common effects (Better Health Channel).
• 45 mg a day or more raises gastrointestinal effects (NIH); it is also the NHMRC adult Upper Level.
• If you take prescription medicines, check with your doctor, pharmacist or our naturopaths before starting.