PUFAs

Polyunsaturated fatty acids (PUFAs) are fatty acids containing two or more carbon–carbon double bonds. They are a major type of dietary fat and are classified into omega-3 and omega-6 families based on the position of the first double bond from the methyl end of the molecule. The essential fatty acids linoleic acid (LA, 18:2 n-6) and alpha-linolenic acid (ALA, 18:3 n-3) must be obtained from the diet because humans cannot synthesize them. The body can convert ALA to longer-chain omega-3s such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), though the conversion rate is limited.

PUFAs serve as structural components of cell membranes, influence membrane fluidity, and act as precursors to signaling molecules called eicosanoids. EPA and DHA are associated with anti-inflammatory effects and have been linked to benefits in cardiovascular and brain health in some studies; LA contributes to various physiological processes, and arachidonic acid (ARA) is another omega-6 end product involved in inflammation regulation.

Dietary sources of PUFAs include fatty fish and fish oils (EPA and DHA), flaxseed, chia seeds, walnuts (ALA), and common vegetable oils such as soybean, corn, and canola (LA and other omega-6). Diets often have a high omega-6 to omega-3 ratio, and guidelines typically recommend increasing omega-3 intake to balance this.

PUFAs are more prone to oxidation than saturated fats, requiring proper storage and, in some cases, antioxidants to prevent rancidity. They are sensitive to heat and light, so cooking methods and shelf life should be considered. Excessive intake of omega-3 supplements can affect bleeding risk in some individuals.