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，膳食中omega-6多不饱和脂肪酸(PUFA)的比例，主要以软脂酸(LA)的形式存在，与omega-3多不饱和脂肪酸相比大幅增加。我们饮食结构的这种变化被认为是导致omega-3状态降低的一个重要因素，特别是二十二碳六烯酸(DHA，22：6n-3)。然而，海洋omega-3脂肪酸来源的大幅增加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omega-3地位下降的问题。据认为，膳食中LA的高摄入量与从α-亚麻酸(ALA，18：3n-3)合成DHA的竞争，从而导致人群的低DHA状态。我们将使用一种新兴但强大的营养和代谢评估技术-化合物特定同位素分析-基于碳-13水平的自然变化来跟踪特定omega-3脂肪酸的代谢命运。具体地说，在高LA和低LA背景饮食中，葵花将被评估为高omega-3植物来源，与亚麻籽油相比，DHA的合成和周转更快。在存在高或低LA背景饮食的情况下，小鼠将被平衡于高碳-13藻类DHA饮食。6周后，动物将维持在LA背景饲料中，并从藻类DHA转换为低碳-13葵花油、亚麻籽油或鱼DHA饲料。将测定组织和血液中omega-3碳-13含量的变化，并测定合成和周转率。葵花油，由于其特殊的omega-3脂肪酸特征，将能够比亚麻籽更快地合成和转化血液和组织中的DHA。因此，葵花油可能为海洋来源的omega-3提供一种可持续的、生态和环境可持续的替代品，与亚麻籽油相比具有更好的优势。此外，这项研究的结果将有助于扩大加拿大的紫薇农业业务，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.