Rita Go Wong


The calcium, phosphorus and magnesium retention of six female phenylketonuric children was studied to determine whether the percentage retention of these minerals would be comparable to the values for normal children established by Lutwak and Macy. 73,78,79 A constant diet was given to the subjects and carmine was used as stool marker. The food and fecal specimens were analyzed for calcium, phosphorus, magnesium and total lipids. Urinary specimens were analyzed for calcium, phosphorus, magnesium and creatinine. Calcium and magnesium levels were determined in the serum of four subjects. The percentage of retention of calcium, phosphorus and magnesium was determined from the intake and output.

The phenylketonuric children were found to be ingesting both calcium and vitamin D in amounts greater than normal children and the Recommended Dietary Allowance levels, with a mean intake of 1.50 gm. per day and 698.4 I.U. respectively. Fecal calcium excretion varied with the amount of calcium intake with a mean of 1.12 gm. per day. A higher percentage of calcium excretion was observed in children with higher calcium intake, while the per cent retention of calcium was found to be higher in patients receiving a lower calcium intake. Negative calcium balance was found in one subject. The range of urinary excretion was lower than in normal children even when a high calcium level was ingested. Three subjects showed below normal serum calcium in spite of their high percentage of calcium retention. High calcium ingestion appeared to increase fecal fat excretion. A correlation appeared to exist between high calcium, low protein intake and high fecal fat excretion in one subject.

The dietary phosphorus intake was found to be lower than in normal children. The calcium to phosphorus ratio in the diet was 2:1. The ratio seemed to influence both calcium and phosphorus retention. The amount of urinary phosphorus was lower than that excreted by normal children. Children who were ingesting the same level of phosphorus as normal children absorbed calcium and phosphorus comparable to normal levels and most children showed a percentage retention of phosphorus above normal consistent with lower phosphorus intake. Magnesium ingestion by subjects was lower than that of normal children. However, the per cent retention of magnesium was above normal with a mean of 26.8 percent. Furthermore, a normal serum, magnesium level was found in three children. A normal urinary creatinine excretion was found in three children.

It was concluded that phenylketonuric children were capable of maintaining normal calcium, phosphorus and magnesium balance even in the presence of high calcium ingestion.


73. Lutwak, L., L. Laster, et al. "Effects of High Dietary Calcium and Phosphorus on Calcium, Phosphorus, Nitrogen and Fat Metabolism in Children,” American Journal of Clinical Nutrition, 14:76-82, February, 1964.

78. Macy, Icie G. Nutrition and Chemical Growth in Childhood. Vol. I. Illinois: Charles C. Thomas, 1942. 432 pp.

79. Macy, I. G., H. J. Kelly. Chemical Anthropology: A New Approach to Growth in Children. Chicago: The University of Chicago Press, 1957. 149 pp.

LLU Discipline





Graduate School

First Advisor

Phyllis B. Acosta

Second Advisor

Donald W. Jones

Third Advisor

Irma B. Vhymeister

Fourth Advisor

David C. Boyle

Fifth Advisor

Barbara J. Myers

Degree Name

Master of Science (MS)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Phenylketonuria -- in infancy & childhood.



Page Count

viii; 76

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website


Loma Linda University. Del E. Webb Memorial Library. University Archives

Included in

Nutrition Commons