A pilot study on protein metabolism in the Papua New Guinea highlanders.

Publisher Website
Google Scholar
Abstract
To clarify the nutritional enigma of the healthy, strong physique of Papua New Guinea (PNG) highlanders who have a protein-deficient diet mainly composed of sweet potato, a pilot study was performed with 10 volunteers of PNG highlanders, and with 8 Japanese controls, 1 group of whom took an experimental protein-deficient diet in Japan. In 4 groups of subjects [adults of PNG highlanders, their children, Japanese controls who were having standard Japanese food (SPD) and those who were having a low protein diet (0.5 g/kg) for 2 wk (LPD)] urea metabolism was investigated after oral administration of 15N urea. By tracing the cumulative excretion of 15N in urine successively for .apprx. 10 days after 15N urea administration, it was found that children of PNG highlanders can retain a large amount of 15N in the body, Japanese controls of LPD fairly well, PNG adult slightly and the Japanese controls of SPD the least of the 4 groups. The 15N atom% excess in the plasma protein of PNG adults, children and Japanese control of LPD is maintained in the range of 0.02-0.05% fluctuating for 10 days after 15N urea administration. 15N atom% excess in plasma protein of Japanese control of SPD was within the scope of error (0.01%). 15N atom% excess in the lysine fraction of the hydrolysate of plasma protein was in the range of 0.01-0.05% in a large number of cases of PNG subjects and Japanese control of LPD; it was not significantly detectable in Japanese controls of SPD, 15N atom% excess in essential and nonessential amino acids of the hydrolysate was significantly detectable in most cases of PNG subjects and Japanese controls of LPD, but not in the case of Japanese controls of SPD. 15N urea may be utilized in PNG highlanders and Japanese controls of LPD to produce amino acids, especially lysine in the intestine where the bacterial species are changed by a long-continued protein-deficient diet from those of Japanese controls of SPD. The possibility of urea recycling was verified.

This publication has 1 reference indexed in Scilit: