Check daily iron intake against needs.
Dietary iron comes in two forms that behave very differently. Heme iron from meat, fish and poultry is absorbed at roughly 25 percent regardless of what else is on the plate. Non-heme iron from plants, eggs and fortified cereals is absorbed at only about 5 percent, roughly doubling to 10 percent when vitamin C is eaten in the same meal. That is why the absorbed figure, not the total, explains why a high-iron plant-based diet can still leave someone deficient.
Bioavailable iron
Absorbed mg = heme mg x 0.25 + non-heme mg x (0.10 with vitamin C, else 0.05)
These figures are population-average estimates for general planning only and are not medical or dietetic advice. Individual energy and nutrient needs vary widely with body composition, activity, medication and health status. Consult a qualified health professional or registered dietitian before making significant changes to what you eat, and especially if you are pregnant or breastfeeding, are under 18, or have a medical condition or a history of disordered eating.
Commonly 8 mg a day for adult men and post-menopausal women, 18 mg for menstruating women and about 27 mg during pregnancy. Set the target field to match your own guidance.
Tea and coffee tannins, calcium supplements and dairy taken with the meal, and the phytates in whole grains and legumes all reduce non-heme absorption substantially. Moving tea and coffee an hour away from iron-rich meals is the single easiest fix.
Because it is — the body absorbs only a small fraction of dietary iron, and absorption rises when stores are depleted. The absorbed number is the honest one, which is why iron targets are set several times higher than the body's actual daily loss of about 1-2 mg.