Jones P J, Pencharz P B, Clandinin M T
Am J Clin Nutr. 1985 Nov;42(5):769-77. doi: 10.1093/ajcn/42.5.769.
Whole body oxidation of dietary stearic, oleic, and linoleic acid was measured in males consuming a test diet of normal foods at a level commensurate with energy requirements for 16 days. Labeled stearic, oleic or linoleic acid was consumed with the breakfast meal on either day 8, 11, or 14. Breath samples were analyzed for total CO2 content and 13CO2 abundance. Breath enrichment of 13CO2 after ingestion of labeled substrate was calculated over background 13C abundance with diet only and expressed as fraction of substrate dose absorbed. Fecal excretion of labeled and diet fatty acids was determined for pooled stool collections. Stearic, oleic, and linoleic acids were separated from fecal fat extracts and combusted to determine 13CO2 enrichment over background. Both dietary and labeled stearic acid were less well absorbed than either oleic or linoleic acids. At hours 7-9 after ingestion of the labeled breakfast, significant differences in percent of absorbed dose excreted in breath were observed between all three fatty acids. Significant differences were observed in apparent amounts of labeled oleate, linoleate, and stearate oxidized after 3 to 9 h. This difference in fatty acid oxidation challenges the assumption that dietary fat is oxidized at a rate independent of its long chain fatty acid composition.
在16天内，让男性食用符合能量需求水平的正常食物组成的试验饮食，测量膳食硬脂酸、油酸和亚油酸的全身氧化情况。在第8天、11天或14天的早餐中摄入标记的硬脂酸、油酸或亚油酸。分析呼吸样本中的总二氧化碳含量和13CO2丰度。计算摄入标记底物后呼吸中13CO2的富集量相对于仅饮食时的背景13C丰度，并表示为吸收的底物剂量的分数。对收集的混合粪便测定标记脂肪酸和膳食脂肪酸的粪便排泄量。从粪便脂肪提取物中分离出硬脂酸、油酸和亚油酸，并燃烧以确定相对于背景的13CO2富集量。膳食硬脂酸和标记硬脂酸的吸收都不如油酸或亚油酸。在摄入标记早餐后7 - 9小时，观察到所有三种脂肪酸在呼吸中排泄的吸收剂量百分比存在显著差异。在3至9小时后，观察到标记油酸、亚油酸和硬脂酸氧化的表观量存在显著差异。脂肪酸氧化的这种差异对膳食脂肪以与其长链脂肪酸组成无关的速率被氧化这一假设提出了挑战。
