Effects of beef-and fish-based diets on the kinetics of n-3 fatty acid metabolism in human subjects
Effects of beef-and fish-based diets on the kinetics of n-3 fatty acid metabolism in human subjects
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DOI：
10.1093/ajcn/77.3.565
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发表时间：
2003-03-01
影响因子：
7.1
通讯作者：
Salem, N
中科院分区：
文献类型：
--
作者：
Pawlosky, RJ;Hibbeln, JR;Salem, N
背景：膳食中多不饱和脂肪酸（PUFAs）的数量和类型可以改变人体必需脂肪酸的代谢。富含20碳和22碳PUFAs的饲料可能抑制去饱和酶的表达或活性，并减少长链不饱和脂肪酸的合成。目的：从理论上讲，与以牛肉为基础的饲料相比，以鱼为基础的饲料中的脂肪含量会抑制n-3脂肪酸的体内代谢动力学。设计：采用室室模型，从10名受试者的血浆浓度时间曲线（pentadeuterated (d(5)) 18:3n- 3,20:5 n- 3,22:5 n-3和22:6n-3）中确定动力学速率常数系数。在3周的时间里，受试者报告了他们平常饮食中的食物摄入量，然后吃了3周的牛肉饮食，然后再吃了3周的鱼饮食。受试者在第3、6和9周摄入1 g d(5)-18:3n-3乙酯。在168小时内抽血并分析血浆中的脂肪酸。测定了n-3脂肪酸代谢动力学常数系数和底物利用率。结果：在所有饮食中，血浆18:3n-3用于长链PUFA合成的比例小于1%。以鱼为基础的饲料与以牛肉为基础的饲料相比，调节同位素从22:5n-3隔间转移到22:6n-3隔间的速率常数系数值降低了70%。血浆d(5)-22:6n-3周转率也降低。结论：鱼基饮食对n-3代谢动力学的主要影响涉及抑制22:5n-3合成22:6n-3的过程。这些过程可能涉及一个响应血浆浓度22:6n-3的反馈控制机制系统
Background: The quantity and type of dietary polyunsaturated fatty acids (PUFAs) can alter essential fatty acid metabolism in humans. Diets rich in 20- and 22-carbon PUFAs may inhibit desaturase expression or activity and decrease the synthesis of long-chain unsaturated fatty acids.Objective: It was theorized that the fat content of a fish-based diet would inhibit the kinetics of the in vivo metabolism of n-3 fatty acids compared with a beef-based diet. Design: A compartmental model was used to determine the coefficients of the kinetic rate constants from the plasma concentration time curves of pentadeuterated (d(5)) 18:3n-3, 20:5n-3, 22:5n-3, and 22:6n-3 of 10 subjects who subsisted on 3 diets with different long-chain PUFA contents. For 3 wk, subjects reported their food intake from their usual diets and then consumed a beef-based diet for 3 wk and then a fish-based diet for an additional 3 wk. Subjects consumed 1 g d(5)-18:3n-3 ethyl ester at weeks 3, 6, and 9. Blood was drawn over 168 h and the plasma analyzed for fatty acids. The coefficients of the kinetic constants of n-3 fatty acid metabolism and the percentage utilization of the substrates were determined.Results: Across all diets, < 1% of plasma 18:3n-3 was utilized for long-chain PUFA synthesis. There was a 70% reduction in the value of the rate constant coefficient that regulated transfer of the isotope from the 22:5n-3 compartment to 22:6n-3 when the fish-based diet was compared with the beef-based diet. The turnover rate of plasma d(5)-22:6n-3 also decreased.Conclusions: The primary effect of a fish-based diet on the kinetics of n-3 metabolism involves processes that inhibit the synthesis of 22:6n-3 from 22:5n-3. These processes may involve a system of feedback control mechanisms responsive to the plasma concentration of 22:6n-3