A novel isotope ratio mass spectrometry method for the characterization of the effects of linoleic acid intake on DHA synthesis and turnover rates

在过去的一个世纪里，与omega-3 PUFA相比，饮食中omega-6多不饱和脂肪酸（主要以油酸（LA）的形式存在）的比例大幅增加。我们饮食模式的改变被认为是omega-3含量降低的重要原因，尤其是二十二碳六烯酸（DHA, 22:6n-3）。然而，大量增加海洋来源的omega-3脂肪酸在生态上是不可持续的，需要替代和可持续的植物来源来解决人口中omega-3脂肪酸水平降低的问题。人们认为，高LA膳食摄入量与α -亚麻酸（ALA, 18:3n-3）合成DHA竞争，从而导致人群DHA水平低。我们将使用一项新兴但功能强大的营养和代谢评估技术——化合物特异性同位素分析——根据碳-13水平的自然变化，追踪特定omega-3脂肪酸的代谢命运。具体来说，与亚麻籽油相比，Ahiflower将被评估为高omega-3植物来源，在高和低LA背景饮食中都能更快地合成和转化DHA。小鼠将在高或低LA背景饮食中平衡高碳-13藻类DHA饮食。6周后，动物将继续使用LA背景饲料，并从藻类DHA饲料转向低碳-13的阿希花油、亚麻籽油或鱼类DHA饲料。组织和血液中omega-3碳-13含量的变化将被确定，合成和周转率也将被确定。由于其特有的欧米伽-3脂肪酸结构，阿希米花油能够比亚麻籽更快地合成和转化血液和组织中的DHA。因此，与亚麻籽油相比，Ahiflower油可以提供一种可持续的，生态和环境可持续的替代海洋来源的omega-3。此外，本研究的结果将有助于扩大加拿大的阿希花农业业务，并为加拿大人创造新的就业机会。

Over the past century, the ratio of dietary omega-6 polyunsaturated fatty acids (PUFA), primarily in the form oflinoleic acid (LA), has increased substantially compared to omega-3 PUFA. This change in our dietary patterns is believed to be a significant contributor to a lower omega-3 status, particularly in docosahexaenoic acid (DHA, 22:6n-3). However, substantial increases to marine sources of omega-3 fatty acids are ecologically unsustainable and alternative and sustainable plant sources are required to address lowered omega-3 status of the population. It is believed that the high dietary intake of LA competes with the synthesis of DHA from alpha-linolenic acid (ALA, 18:3n-3) thereby contributing to the low DHA status of the population. We will use an emerging but powerful technology for nutrition and metabolic assessment - compound-specific isotope analysis - to track the metabolic fate of specific omega-3 fatty acids based on natural variations in carbon-13 levels. Specifically, Ahiflower will be assessed as a high omega-3 plant source for a more rapid synthesis and turnover of DHA compared to flaxseed oil on both a high and low LA background diet. Mice will be equilibrated to high carbon-13 algal DHA diets in the presence of either high or low LA background diet. After 6 weeks, animals will be maintained on the LA background diet and switch from algal DHA to a low carbon-13 Ahiflower oil, flaxseed oil or fish DHA diet. Changes in omega-3 carbon-13 content of tissues and blood will be determined and synthesis and turnover rates determined. Ahiflower oil, due to it's specific omega-3 fatty acid profile will be able to synthesis and turn over DHA in blood and tissues faster than flaxseed. Therefore, Ahiflower oil may provide a sustainable, ecologically and environmentally sustainable alternative to marine sources of omega-3 that is superior compared to flaxseed oils. Furthermore, the results of this study will serve to expand the Ahiflower agriculture business in Canada and create new jobs for Canadians.