Short answer: organ meats top the list, and beef liver leads it at roughly 6.5 mg of heme iron per 100 g cooked, with kidney and heart close behind. Then come red meats like beef and lamb, then shellfish such as oysters and mussels, then dark poultry and oily fish like sardines. Heme iron exists only in animal foods, and it's the form the body absorbs at roughly 15–35%, versus roughly 2–20% for the non-heme iron in plants and most supplement tablets.
The list, densest first
- Beef liver: roughly 6.5 mg per 100 g cooked. The densest common heme-iron food, and it brings company: about 70 µg of B12 per 100 g, plus folate, copper, preformed vitamin A and choline.
- Other organ meats: kidney and heart both land in the several-milligrams-per-100 g range; kidney is also notably dense in selenium and B12, heart is one of the richest food sources of CoQ10.
- Beef and lamb: roughly 2–3 mg per 100 g cooked for beef; lamb sits in a similar band. The everyday workhorses.
- Oysters and mussels: roughly 5–7 mg per 100 g cooked, though a chunk of shellfish iron is non-heme; still an excellent haul either way.
- Dark poultry and sardines: roughly 1–3 mg per 100 g. Modest, but it adds up in a normal week.
One nuance worth knowing: even in meat, not all the iron is heme; a large share is, and the rest is non-heme travelling with it. The rough figures above are total iron from standard food-composition data, which is why "roughly" is doing honest work in every line.
Why density matters more than it looks
Health Canada's recommended iron intake for women 19–50 is 18 mg per day (8 mg for men). Hitting 18 mg from chicken breast and salad is a long day of eating. Hitting a meaningful share of it from foods where iron arrives in the well-absorbed heme form is a much shorter list of decisions, and liver shortens it the most. It's not that spinach is bad; it's that spinach's non-heme iron absorbs at the 2–20% rate and gets further sandbagged by coffee, tea and calcium. The heme foods above mostly don't care what you drank with them.
The honest catch: nobody eats this list
Here's the flaw in every heme-iron listicle, ours included: the top entries are the ones that vanished from Canadian kitchens two generations ago. Oysters are a date night, not a Tuesday. Kidney is a hard sell at any hour. And liver, the single densest item, is the one most people flatly refuse to cook. A list you won't eat delivers exactly zero milligrams.
The practical route to the top of the list
This is the actual reason freeze-dried liver capsules exist. Rise Grass-Fed Beef Liver Capsules are the number-one food on this page with the flavour problem removed: one ingredient (freeze-dried grass-fed, grass-finished beef liver) in a gelatin capsule, NPN certified with Health Canada. The serving is 4 capsules a day, equal to 3,000 mg of freeze-dried liver, and the 120-capsule bottle is $39.99 for a 30-day supply, about $1.33 a day. Keep eating the steak and the occasional oyster; the capsules cover the entry you were never going to pan-fry.
FAQ
Do any plant foods contain heme iron?
No. Heme iron comes from hemoglobin and myoglobin, so it exists only in animal foods. Plants (lentils, spinach, tofu, fortified cereals) supply non-heme iron, absorbed at roughly 2–20%.
Is liver really higher in iron than steak?
Yes, by a wide margin: roughly 6.5 mg per 100 g cooked versus roughly 2–3 mg for beef muscle cuts. Liver also carries B12, folate and copper that work alongside iron in red blood cell formation.
Are oysters a good iron source?
Very good: roughly 5–7 mg per 100 g cooked, though part of shellfish iron is the non-heme form. As an occasional food they're excellent; they're just hard to eat daily.
How often should I eat heme-iron foods?
Regularly: iron needs are daily (18 mg for women 19–50, 8 mg for men, per Health Canada). If you suspect you're actually low rather than just under-eating iron, ask your practitioner for a ferritin test instead of guessing.
Written by the team at Rise Nutrition, Toronto, Canada's single-ingredient ancestral nutrition brand. The old foods, freeze-dried, one per label. Questions? ray@risenutritions.ca
