Quercetin as a Preservative in Fish Oils

Fish oils are a source of long chain fatty acids that feed into the essential fatty acid pathways in humans. This means that fish oils can help modulate the cellular need for essential fats to make important cellular hormones. Supplementing fish oils is therefore seen as beneficial to the health. However, fish oils are susceptible to oxidation because they are polyunsaturated, and this gives them a propensity to oxidise under conditions of heat and light. Adding antioxidants to fish oils can therefore preserve the delicate oils and may improve the health effects. Quercetin is a flavonoid antioxidant that has the potential to protect fish oils from oxidation. However, studies show that when added to the oils, quercetin can react with the oils to form ester derivatives of quercetin. This shows that protecting delicate oils is not as simple as adding antioxidants, as it is unknown what health effects quercetin esters may have. The best antioxidant to protect fish oils still appears to be vitamin E, something found naturally in most oils. 

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Liu, S., Zhu, Y., Liu, N., Fan, D., Wang, M. and Zhao, Y. 2021. Antioxidative properties and chemical changes of quercetin in fish oil: Quercetin reacts with free fatty acids to form its ester derivatives. Journal of Agricultural and Food Chemistry. 69(3): 1057-1067

About Robert Barrington

Robert Barrington is a writer, nutritionist, lecturer and philosopher.
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