Iron absorption from experimental infant formulas based on pea (Pisum sativum)-protein isolate: the effect of phytic acid and ascorbic acid

Infant formula based on pea (Pisum sativum)-protein isolate has been sugges ted as an alternative to soyabean formula in countries where soyabean is no t a native crop, or when soyabean protein cannot be used due to allergic re actions or intolerances. In the present study, Fe absorption from experimen tal infant formulas based on pea-protein isolate was measured in healthy no n-anaemic young women. The influence of phytic acid and ascorbic acid on Fe absorption was evaluated, using a stable-isotope technique based on incorp oration of Fe stable-isotope labels into erythrocytes 14 d after administra tion. Geometric mean Fe absorption increased from 20.7 (+1SD 41.6, -1SD 10. 3) % to 33.1 (+1SD 58.6, -1SD 18.7) %; (P < 0.0001; n 10) after enzymic deg radation of virtually all phytic acid. Doubling the molar ratio Fe:ascorbic acid from 1 : 2.1 to 1 : 4.2 in the infant formula with native phytic acid content also increased Fe absorption significantly (P < 0.0001; n 10); geo metric mean Fe absorption increased from 14.8 (+1SD 32.1, -1SD 6.8) % to 22 .1 (+1SD 47.2, -1SD 10.4) %. These results confirm the inhibitory and enhan cing effects of phytic acid and ascorbic acid respectively on Fe absorption , but also indicate relatively high fractional Fe absorption from the pea-p rotein-based formulas. After adjusting for differences in Fe status, our da ta indicate that Fe absorption from dephytinised pea protein might be less inhibitory than dephytinised soyabean protein as measured in a previous stu dy (Hurrell et al. 1998).