Journal of Nutrition Vol. 59 No. 3 July 1956, pp. 393-406
Copyright
Studies in Calcium Metabolism. Effect of Food Phytates on Calcium45 Uptake in Boys on a Moderate Calcium Breakfast1,2,3,4,
Two Figures
Felix Bronner5 and
Robert S. Harris
Department of Food Technology
Constantine J. Maletskos
Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts
Clemens E. Benda
Department of Neuro-psychiatry, Harvard Medical School, Boston, and Walter E. Fernald State School, Waverley, Massachusetts
- 1. Seventeen boys were given two test breakfasts, one of oatmeal and one of farina, at an interval of three weeks, for the purpose of comparing calcium uptake in the presence and in the absence of food phytate. The boys had subnormal intelligence but were otherwise normal, were institutionalized under relatively uniform conditions. The two test breakfasts contained, respectively: 220 and 220 ml of milk; 241 and 237 mg of Ca., 80 and 0 mg phytic P; and 0.85 and 0.85 µc of Ca45. Ca uptake was studied by determining the Ca45 contents of the serum samples taken 2.5 hours following ingestion of the test breakfast, and by measuring the Ca45 output in pooled urine and stool specimens collected for 72 and 120 hours, respectively, following ingestion of the Ca45-labeled meals.
- 2. The specific activities of the serum and urine samples obtained from these subjects were not significantly changed when the cereal of the test breakfast was changed from oatmeal to farina, or the reverse.
- 3. For purposes of a criss-cross design the individuals had been divided into two subgroups. The fecal output of Ca45 of each subgroup was affected significantly by changing the cereal of the test breakfast from oatmeal to farina. However, the direction of change was opposite for each subgroup. When the results of the fecal output of the two subgroups were pooled, the difference between the two test breakfasts was no longer significant.
- 4. The percentage of absorbed Ca decreased as the Ca intake increased.
- 5. It is concluded that phytates do not exert a significant effect on Ca45 absorption when the meal provides 239 mg of Ca and when the phytic P intake is 80 mg. Because this ratio of Ca to phytic P is typical of diets in the United States, it may be concluded that food phytates are of no nutritional concern in this country.
1 Presented at the Annual Meeting of the American Institute of Nutrition, Chicago, Illinois, April 610, 1953. Contribution no. 276, from the Department of Food Technology, Massachusetts Institute of Technology.
2 Partial support for this study came from grants by the Quaker Oats Company, by the Atomic Energy Commission, Contract AT (20-1)-952, and by National Institutes of Health.
3 The data in this publication are taken from the dissertation presented (1952) by Felix Bronner to the Department of Food Technology, Massachusetts Institute of Technology, in partial fulfillment of the requirements for the degree of Doctor of Philosophy.
4 Authorization for the use of restricted quantities of Ca45 in patients institutionalized for mental inadequacy was granted through the Subcommittee on Human Applications by the Isotope Division of the Atomic Energy Commission. The Ca45 was obtained on allocation from the Oak Ridge National Laboratory.
5 Quaker Oats Fellow, 195051. Present address: The Rockefeller Institute for Medical Research, New York 21, N. Y.
Manuscript received 4 February 1956.