Masters Theses

Date of Award

6-1979

Degree Type

Thesis

Degree Name

Master of Science

Major

Nutrition

Major Professor

Gail W. Disney

Committee Members

Rossie L. Mason, Ada Marie Campbell

Abstract

This study was designed to accomplish two objectives. The first objective was to determine the relationship between the dietary intake of magnesium and urinary excretion of magnesium:creatinine in first void urine samples from preadolescent girls. The other objective was to evaluate the effects of age, race and income level on the dietary intake and urinary excretion of magnesium in a first void urine sample.

Dietary intakes and urinary magnesium:creatinine ratios were evaluated during a 2 year longitudinal period in approximately 100 preadolescent girls who were 9±0.5 years of age at the beginning of the study. These girls were participants in the S-87 Southern Regional Nutrition Project. The racial distribution for the girls was 50 percent white and 50 percent black. Fifty percent of the girls were from upper income families ($2,000 or more/person/year) and 50 percent were from lower income families ($1,000 or less/ person/year).

Magnesium in the first void urine sample was determined by atomic absorption spectrophotometry. Urinary creatinine was determined by Folin's Method. Mean dietary intakes and urinary magnesium:creatinine ratios were calculated. Due to the small size of the sampling distribution for each age group, it was not possible to calculate the regression of dietary intakes of magnesium and urinary excretion of magnesium:creatinine for each race and income level on age. The Student's t-test was used for testing the differences between the 2 races and between the 2 income groups with regard to mean dietary magnesium intakes and the urinary excretion of magnesium, creatinine and magnesium:creatinine. Pearson correlation coefficients between dietary and urinary variables were determined.

The sample size for each age group was not large enough to make inferences to the population; therefore, the data for each age group were combined by race and income level. Whites had a significantly greater (P < 0.05) mean dietary magnesium intake than did blacks, but there was not a significant difference between income levels. The greatest percentage of subjects met 67 to 100 percent of the RDA for magnesium. Correlations among total dietary protein, calcium, phosphorus, and magnesium were highly significant (P < 0.01). Blacks had a significantly greater (P < 0.01) excretion of creatinine than did whites. There were no specific trends in excretory patterns of magnesium by race and income groups.

Because statistical analyses did not show a relationship between the dietary intake of magnesium and urinary excretion of magnesium:creatinine, it was not possible to develop a standard based on creatinine from a first void urine sample. The development of such a standard would prove very useful in a large field study where 24-hour urine collections are difficult.

Download
Files over 3MB may be slow to open. For best results, right-click and select "save as..."

Included in

Nutrition Commons

Share

COinS