With reference to human diet, which one of the following is an essential fatty acid?

Essential fatty acids (EFAs) are polyunsaturated fatty acids that the human body cannot synthesize endogenously due to the lack of specific desaturase enzymes and must therefore be obtained through the diet [t7]. There are two primary classes of EFAs: the omega-6 series, derived from linoleic acid (LA), and the omega-3 series, derived from alpha-linolenic acid (ALA) [t3][t9]. Linoleic acid is a common 18-carbon polyunsaturated fatty acid found in vegetable oils like safflower and soybean [t3][t4]. In contrast, oleic acid is a monounsaturated omega-9 fatty acid that the body can produce, making it non-essential [t5][t6]. Stearic acid is a saturated fatty acid that can also be synthesized by the body [t2][t6]. Butyric acid is a short-chain fatty acid typically produced by gut microbiota or found in dairy, but it is not classified as an essential fatty acid [c1].

Sources

1. [1] https://pmc.ncbi.nlm.nih.gov/articles/PMC5492028/
2. [2] https://www.eatforhealth.gov.au/nutrient-reference-values/nutrients/fats-total-fat-fatty-acids
3. [3] https://www.nature.com/scitable/topicpage/fatty-acid-molecules-a-role-in-cell-14231940/
4. [4] Science , class X (NCERT 2025 ed.) > Chapter 2: Acids, Bases and Salts > Table 2.3 Some naturally occurring acids > p. 28