Bioavailability of zinc in milk and soy protein-based infant formulas.
Total femur zinc of young rats was used to evaluate the biological availability of zinc in milk and soy protein-based infant formulas. A zinc deficient diet (0.8 mug Zn/g) containing egg white protein was supplemented with graded levels of zinc from zinc sulfate, milk and soy protein-based infant formulas. A plot of total femur zinc (log) after feeding the diet for 3 weeks versus the zinc added to the diet gave a linear relationship over the range of 0, 3, 6, 9 and 12 mug/g added zinc. By using a slope-ratio bioassay model, the relative biological availability of endogenous and added zinc in milk-based formula was estimated to be 0.86 and that of soy-based formula 0.67 (zinc sulphate = 1.00) with corresponding 95% fiducial limits being 0.82 to 0.91 and 0.62 to 0.71. Thus, to provide equivalent amounts of available zinc, the total zinc content of the soy protein-based formula would need to be at least 20% higher than that of the formula containing milk protein.
D000818:Animals; D001835:Body Weight; D001842:Bone and Bones / Q000378:metabolism*; D003677:Deficiency Diseases / Q000178:diet therapy; D004032:Diet; D004305:Dose-Response Relationship, Drug; D005269:Femur / Q000033:anatomy & histology / Q000378:metabolism; D007225:Infant Food; D008297:Male; D008892:Milk; D009929:Organ Size; D014674:Plant Proteins, Dietary; D051381:Rats; D013025:Glycine max; D015032:Zinc / Q000172:deficiency / Q000378:metabolism* / Q000627:therapeutic use
D014674:Plant Proteins, Dietary; D015032:Zinc