Oxidation of Polyunsaturated Fatty Acids and its Impact on Food Quality and Human Health
*Corresponding author: Ling Tao*
Tao L. Oxidation of polyunsaturated fatty acids and its impact on food quality and human health. Adv Food Technol Nutr Sci Open J. 2015; 1(6): 135-142. doi: 10.17140/AFTNSOJ-1-123
© 2015 Tao L. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
For many years, both preclinical and clinical studies have provided evidences to support the beneficial effects of ω-3 Polyunsaturated fatty acids (PUFAs), particularly Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) in the prevention of chronic diseases. However, recently, an increasing number of studies reported adverse or contradictory effects of ω-3 PUFAs on human health. While dose and experimental condition need to be considered when evaluating these effects, oxidation of PUFAs also serves as an important factor contributing to the inconsistent results. In fact, oxidation of PUFAs happens frequently during food processing and storage, cooking and even after food ingestion. The free radicals and metabolites generated from PUFA oxidation may adversely affect food quality and shelf life by producing off-flavors and reducing nutritional values. The impact of PUFA oxidation in human health is more complicated, depending on the concentration of products, disease background and targets. This review will introduce different types of PUFA oxidation, discuss its impact on food quality and human health and provide some thoughts for the future research directions.
ALA: α-Linolenic acid; LOX: Lipoxygenase; COX: Cyclooxygenase; MaR: Maresin; CYP: Cytochromes P450; PD/NPD: Protectin/neuroprotectin; DHA: Docosahexaenoic acid; PL: Phospholipase; EPA: Eicosapentaenoic acid; PUFA: Polyunsaturated fatty acid; GST: Glutathione S-transferase; RvD: D-series resolvin; HHE: 4-Hydroxy-2-hexenal; RvE: Eseries resolvin; HNE: 4-Hydroxy-2-nonenal; FAO: Food and Agriculture Organization; WHO: World Health Organization; AHA: American Heart Association.
Over the past few decades, chronic diseases including cardiovascular diseases, obesity, diabetes and cancer have increased rapidly in the USA and other countries of the world.1 Diet and nutrition are important factors in the maintenance and promotion of good health throughout the entire life. By far, both preclinical and clinical studies have shown that ω-3 Polyunsaturated fatty acids (PUFAs) in particular Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA) exert heath beneficial effects on cardiovascular diseases, diabetes, cancer and so on.2-5 This leads to institutions worldwide publishing recommendations on the intake of EPA and DHA. For instance, Food and Agriculture Organization (FAO) and World Health Organization (WHO) recommend adults to take 0.25-2 g EPA+DHA per day.6 American Heart Association (AHA) recommends daily intake of 0.5-1 g EPA+DHA per day per adult.7
However, as reviewed by Weylandt et al more recently, there are controversial results regarding to the health efficacy of ω-3 PUFAs.8 On one hand, the dose and experimental designs may contribute to the variation in results. On the other hand, with the nature of unsaturated bonds, PUFAs are prone to oxidation which generates various metabolites as well as reactive oxygen species. The extent of oxidation and the resulting metabolites may positively or negatively affect the efficacy of PUFAs. This review will introduce different types of PUFA oxidation and discuss the effects of oxidation on food quality and human health.