Linoleic acid (LA) (n−6) and α-linolenic acid (ALA) (n−3) are essential fatty acids (EFAs) as they cannot be synthesized by humans or other higher animals. In the human body, these fatty acids (FAs) give rise to arachidonic acid (ARA, n−6), eicosapentaenoic acid (EPA, n−3) and docosahexaenoic acid (DHA, n−3) that play key roles in regulating body homeostasis. Locally acting bioactive signaling lipids called eicosanoids derived from these FAs also regulate diverse homeostatic processes. In general, ARA gives rise to pro-inflammatory eicosanoids whereas EPA and DHA give rise to anti-inflammatory eicosanoids. Thus, a proportionally higher consumption of n−3 PUFAs can protect us against inflammatory diseases, cancer, cardiovascular diseases, and other chronic diseases. Dietary supplementation with olive oil (MUFA) is also associated with certain changes in immune function which reduces the risk of autoimmune disorders like rheumatoid arthritis but the mechanisms are yet to be clearly elucidated.