Sulfate production depicts fed-state adaptation to protein restriction in humans.
One feature of the adaptation to dietary protein restriction is reduced urea production over the hours after consumption of a test meal of fixed composition. This adaptation is impaired in conventionally treated insulin-dependent diabetes mellitus (Hoffer LJ, Taveroff A, and Schiffrin A. Am J Physiol Endocrinol Metab 272: E59--E67, 1997). We have now tested the response to a test meal containing less protein and included as a main outcome variable the production of sulfate, a specific indicator of sulfur amino acid catabolism. Six normal men consumed a mixed test meal containing 0.25 g protein/kg and 10 kcal/kg while adapted to high (1.5 g x kg(-1) x day(-1)) and low (0.3 g. kg(-1) x day(-1)) protein intakes. They followed the identical protocol twice. Six subjects with insulin-dependent diabetes consumed the test meal while adapted to their customary high-protein diet. Adaptation to protein restriction reproducibly reduced 9-h cumulative postmeal urea N and S production by 22--29% and 49--52%, respectively (both P < 0.05). Similar results were obtained for a postmeal collection period of 6 h. The response of the diabetic subjects was normal. We conclude that reductions in postmeal urea and sulfate production after protein restriction are reproducible and are evident using a postmeal collection period as short as 6 h. Sulfate production effectively depicts fed-state adaptation to protein restriction.
Hamadeh
M J
MJ
Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2.
Schiffrin
A
A
Hoffer
L J
LJ
D000328:Adult; D000409:Alanine / Q000378:metabolism; D001786:Blood Glucose; D002247:Carbon Isotopes; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D018753:Diet, Protein-Restricted; D004044:Dietary Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009587:Nitrogen Isotopes; D019518:Postprandial Period; D013431:Sulfates / Q000378:metabolism*; D014508:Urea / Q000097:blood / Q000652:urine
D001786:Blood Glucose; D002247:Carbon Isotopes; D004044:Dietary Proteins; D009587:Nitrogen Isotopes; D013431:Sulfates; D014508:Urea; D000409:Alanine