Muscle foods enhance the absorption of non-haem iron. We studied the size of the dialysable iron species produced following in vitro digestion of soluble and insoluble chicken muscle proteins and compared the results with those for egg white and whey protein. Digestion of chicken muscle proteins caused a four- to fivefold increase in dialysable iron, whereas egg white showed only a slight increase and whey protein caused a reduction, as compared with the control. All the dialysable iron species produced by egg white and whey were smaller than 1 kDa. In contrast, chicken muscle proteins produced dialysable iron species of all sizes up to 10 kDa, but the majority were in the range 2–3.5 kDa for both soluble and insoluble muscle proteins. Copyright © 2005 Society of Chemical Industry