An investigation of factors influencing the bioavailability of non-haem iron from meat systems

The objective of this study was to examine the effect of meat on the bioavailability of non-haem iron. Dialysability of iron was used as an indicator of non-haem iron bioavailability. All meat systems used (beef, pork, lamb, lamb's liver, chicken breast and leg, venison and salmon) significantly enhanced the dialysability of non-haem iron from a semi-synthetic meal, but whey and gluten were inhibitory. P-lactoglobulin, the main sulphydryl-containing protein of whey, significantly enhanced iron dialysability indicating that it was not the inhibitory component in the whey. Incorporation of N-ethylmaleimide (5 to 10 mM), a sulphydryl-blocking agent, in the semi-synthetic meal, significantly reduced the dialysability of iron. The small molecular weight fraction (MW < 6,000 to 8,000 kDa) significantly enhanced, whereas, the large molecular weight fraction (MW > 6,000 to 8,000 kDa) significantly reduced iron dialysability compared to the complete fraction. It is concluded that both the sulphydryl content of meat and the MW of its protein degradation products are important in determining the effect of the 'meat factor' on the bioavailability of non-haem iron.