Chain shortening of palmitic acid in human subjects.
Chain shortening of palmitic acid was examined in vivo by comparing oxidation rates of [1-13C]palmitate vs [16-13C]palmitate fed to four male subjects consuming a high-fat diet. For 9 d subjects were fed a diet of normal foods providing an energy intake equal to their estimated requirements. The diet provided (as energy) approximately 14% protein, 46% carbohydrate, and 40% fat at a P:S ratio of 0.25. Analysis of breath 13CO2 enrichment on day 3 permitted analysis of background 13C contribution from the test diet alone. On days 4 and 7 either [1-13C]palmitic acid or [16-13C]palmitic acid (9-13.5 mg/kg body wt) was fed with the breakfast meal. The whole-body rate of oxidation of [1-13C]palmitic acid was significantly greater than that observed for [16-13C]palmitic acid. These results suggest that up to 34% of dietary palmitic acid consumed may be subjected to extramitochondrial chain shortening.
Clandinin
M T
MT
Department of Foods and Nutrition, University of Alberta, Edmonton, Canada.
Khetarpal
S
S
Kielo
E S
ES
French
M A
MA
Tokarska
B
B
Goh
Y K
YK
D000328:Adult; D001835:Body Weight; D002247:Carbon Isotopes; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism*; D002149:Energy Intake; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000008:administration & dosage / Q000378:metabolism*
D002247:Carbon Isotopes; D004041:Dietary Fats; D010169:Palmitic Acids; D019308:Palmitic Acid