American Journal of Clinical Nutrition, Vol 15, 331-340, Copyright © 1964 by The American Society for Clinical Nutrition, Inc.

The Effect of a Controlled Increment in Dietary Nutrient Intake on Blood and Urine Biochemistry in Children

¹ From the Institute of Nutrition of Central America and Panama (INCAP), Guatemala, Central America

The study was designed to investigate the effect of a general dietary change on a number of biochemical measurements in the blood and urine of a group of children. The subjects were institutionalized in a home for poor children, in which the socioeconomic situation and the diet were as poor as among low socioeconomic groups in the Central American region. The experimental plan included an initial dietary survey, clinical examination and biochemical determination of hemoglobin, serum vitamin A, carotene, vitamin C, riboflavin, pseudocholinesterase and plasma protein fractions, as well as riboflavin in packed red blood cells. Creatinine, urea nitrogen, thiamine and riboflavin were estimated in urine. The preliminary dietary evaluation revealed marked deficiencies in intake of all nutrients when compared to the National Research Council Recommended Dietary Allowances. The children were then given a controlled diet which raised their nutrient intake to a level sufficiently high to satisfy at least National Research Council recommendations. In the case of vitamin A and vitamin C, this represented approximately a fourfold increase and about a threefold increase for riboflavin. After ten weeks on this improved diet the clinical and biochemical studies were repeated in toto. Several of the biochemical components of blood responded as expected with increases which reflected the higher experimental nutrient intakes, namely, carotene, vitamin C and riboflavin in serum as well as total riboflavin in the red blood cells. The serum vitamin A responded differently. The average level before the experimental diet was low and showed practically no increase during the study. Individually the serum concentration of vitamin A increased in four children, did not change in three and decreased in three. The unexplained discrepancy with the dietary data is evident since the corresponding vitamin A intake calculated per capita was four to five times higher during the experimental period than before the improved diet was instituted. Urinary excretion of thiamine decreased despite the increased intake. The significance of this phenomenon is discussed. Riboflavin and urea excretions in urine increased.