Influence of a Chemically Defined Diet on the Composition of Serum and Urine

Abstract

Abstract We have studied the effects of ingestion of a chemically defined diet on the constituents of serum and urine of five normal volunteers. The diet, believed to meet all human nutritional requirements, caused a decrease in serum cholesterol and urea nitrogen and an increase in serum phosphate, uric acid, and creatinine. Urinary creatinine is unchanged from that of a random diet but urinary electrolytes, urea, and uric acid decrease to a new stable value, which is achieved after four days. High-resolution techniques have been used to measure the carbohydrate-containing constituents of urine and those that can be detected by their ultraviolet absorbance or their reaction with ninhydrin. A considerable decrease in the number of these urinary constituents is effected by the chemical diet within four days, but even by this time all compounds attributable to the random diet may not have been completely eliminated. Many urinary components that persist while the subjects are on the simplified diet have been tentatively identified.