Cereal Chem 58:363 - 366.  |  VIEW ARTICLE
Phytate-Zinc Molar Ratio of Breakfast Cereals and Bioavailability of Zinc to Rats.

E. R. Morris and R. Ellis. Copyright 1981 by the American Association of Cereal Chemists, Inc. 

The concept of the phytate-zinc molar ratio as a predictor of zinc bioavailability to rats was tested with breakfast cereals. Seven ready-to-eat and two quick-cooking breakfast cereals with phytate-zinc molar ratios from 2 to 43 served as dietary sources of zinc. Growth and bone zinc responses of rats were bioassay criteria, and ZnSO4 x 7H2O was the reference zinc compound. Breakfast cereals with phytate-zinc molar ratios of 15 or less supported growth as well as the reference source did, but cereals with higher ratios depressed growth. The bone zinc response was slightly greater to the cereal with a phytate-zinc molar ratio of 3 than to the reference ZnSO4, but the response to all other cereals, including a cereal with a phytate-zinc molar ratio of 2, was less than to the reference compound. The biological response of rats was not directly correlated with dietary fiber in the cereals. The phytate-zinc molar ratio was a major factor affecting bioavailability of zinc in breakfast cereals.