Metabolic Benefits of Plant-based N-3 Polyunsaturated Fatty Acids on Brown Thermogenesis

Authors

Kyung Ho Park, University of Nebraska - LincolnFollow

First Advisor

Sathish Kumar Natarajan

Second Advisor

Soonkyu Chung

Date of this Version

Summer 7-2020

Comments

A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Nutrition, Under the Supervision of Professor Sathish Kumar Natarajan. Lincoln, Nebraska: July, 2020

Copyright 2020 Kyung Ho Park

Abstract

There are two essential fatty acids for humans, a-linolenic acid (ALA) and linoleic acid (LA), which should be taken from foods to maintain health. Once incorporated into cells, ALA and LA, which are omega-3 poly unsaturated fatty acid (n-3 PUFA) and n-6 PUFA respectively, undergo elongation and desaturation to generate longer and more unsaturated fatty acids influencing inflammation and immunological responses. Numerous studies showed a dietary reduction of n-6/n-3 PUFA ratio improves cardiovascular health, inflammation, and insulin resistance. Fish oil, the main resource for n-3 PUFA, is shown to increase these health benefits. In our lab, we investigated the efficacy of ALA-enriched butter (n3Bu) as an alternative to fish oil for n-3 PUFA. n3Bu-fed mice showed increased bioconversion of ALA to long-chain n-3 PUFA (LC n-3 PUFA) and attenuated high fat (HF) diet-induced insulin resistance and inflammation. Besides, these health benefits, n-3 PUFA is shown to improve obesity and its related diseases by regulating lipid metabolism in both white adipose tissue (WAT) and brown adipose tissue (BAT). Fish oil abundant with n-3 PUFA promotes BAT formation and increases its thermogenic activity in cold acclimation. However, the impact of ALA-enriched agricultural products on the BAT function is unknown. In this study, we investigated the effect of ALA-biofortified butter (n3Bu) on lipid metabolism and thermogenic functions in BAT. Intake of n3Bu significantly reduced the whitening of BAT and increased the thermogenesis in response to acute-cold treatment. Consumption of n3Bu promoted bioconversion of LC n-3 PUFA, fatty acid elongation and desaturation, and mitochondrial biogenesis. Taken together, our results support that ALA-biofortified butter is a novel source of n-3 PUFA that potentiates the BAT thermogenic function.

Advisor: Sathish Kumar Natarajan