How much iron you absorb depends on your stores, not just the menu
Absorption runs 14 to 18% on a mixed diet and 5 to 12% without meat, but both figures describe people whose stores are already empty. As those stores fill, the percentages drop.
What the study found
Iron absorption runs 14 to 18% on a mixed diet, 5 to 12% without meat
Both ranges describe people whose stores are already empty, when absorption is turned up as far as it will go. As those stores fill, the percentages fall. So the figure that matters is not fixed by the menu; it moves with the person eating from it.
The caveat · Modelled ranges, not measured ones
These are modelled ranges built from intake data and isotope studies, not measurements taken in one population, which is why they are given as spans rather than single numbers. The review is a narrative one and lists the nature of the meat factor, and the roles of vitamin A and carotenoids, as still unresolved.