Essential Unsaturated Fatty Acids – Their Functions and Sources

Monounsaturated fatty acids, commonly abbreviated as **MUFA**, represent a category of lipids defined by the presence of a single double bond within their carbon chain. This terminology frequently appears in scientific literature and nutritional publications, particularly in discussions concerning health-promoting dietary components. Among the members of this class, **oleic acid** (C18:1) is the most prevalent in daily diets, whereas **elaidic acid** (the *trans* isomer of oleic acid) and **erucic acid** (C22:1) are consumed in smaller quantities. Chemically, all these acids belong to the **n-9 (omega-9) family**, indicating that their double bond is positioned between the ninth and tenth carbon atoms in the fatty acid backbone. Physically, MUFA exist in liquid form at room temperature, distinguishing them from saturated fats, which are solid. Their consumption is associated with multiple health benefits, leading nutritionists to recommend that they constitute **10–20% of total daily energy intake**. Clinical investigations, including a meta-analysis of nine randomized controlled trials, have demonstrated that diets enriched with MUFA — combined with a reduced carbohydrate intake of 37–50% — result in **lower triglyceride levels** and **improved lipid profiles** in individuals with type 2 diabetes, specifically through **reducing LDL cholesterol („bad” cholesterol)** and **increasing HDL cholesterol („good” cholesterol)**. Consequently, patients with dyslipidemia, elevated total cholesterol, or disrupted LDL/HDL ratios are advised to incorporate more MUFA-rich foods into their diets. Furthermore, these fatty acids exhibit **antiatherogenic properties**, enhance skin health, and serve as a cornerstone of the **fertility diet** (as outlined in the Nurses’ Health Study II), the **Mediterranean diet**, and the **DASH dietary pattern** — both of which are recognized as global benchmarks for cardiovascular disease prevention. Research published in the *„Journal of the American Medical Association”* by Spanish scientists indicates that the Mediterranean diet, abundant in MUFA, may not only protect against cancer and cardiovascular diseases but also **reduce the risk of depression**.

Polyunsaturated fatty acids, commonly abbreviated as PUFAs, are characterized by the presence of two or more double bonds within their hydrocarbon chains, which confers a liquid state at ambient temperatures. Unlike monounsaturated fatty acids (MUFAs), they exhibit markedly lower resistance to oxidative degradation—a detrimental chemical reaction triggered by elevated temperatures, exposure to ultraviolet light, and thermal processing techniques such as frying or baking. This class of lipids encompasses two primary families: **omega-3 (n-3)** and **omega-6 (n-6)** fatty acids. The former is principally represented by alpha-linolenic acid (ALA), which undergoes metabolic conversion in the human body to eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), whereas the latter is dominated by linoleic acid (LA), primarily transformed into gamma-linolenic acid (GLA) and arachidonic acid (AA). Excessive intake of n-6 fatty acids has been shown to disrupt the metabolic processing of n-3 fatty acids, thereby perturbing the physiological balance between their derived bioactive compounds. PUFAs also include **essential fatty acids (EFAs)**, which cannot be synthesized *de novo* by the organism and encompass EPA and DHA among others. Dietary guidelines recommend that their energetic contribution constitute at least 7% of total caloric intake. Extensive research corroborates their beneficial effects on skin integrity—exerting moisturizing, reparative, and anti-acne properties. Furthermore, PUFAs are integral components of neuronal cell membranes, influencing nervous system functionality and cerebral operations, while DHA plays a pivotal role in ocular tissue composition and the maintenance of visual acuity. Omega-3 fatty acids demonstrate the capacity to reduce low-density lipoprotein (LDL) cholesterol concentrations, thereby conferring protection against cardiovascular diseases, hepatic disorders, and certain malignancies. The most efficacious approach to lowering blood cholesterol levels involves diminishing saturated fat consumption while concomitantly augmenting PUFA proportions in the diet. Populations adhering to omega-3-rich dietary patterns exhibit reduced incidences of circulatory disorders, neoplastic diseases, and allergic conditions. Additionally, PUFAs contribute to blood pressure regulation. Their adequate intake during childhood—particularly via breast milk—enhances psychomotor development and visual sharpness. Conversely, insufficient PUFA levels in elderly individuals may predispose to psoriasis, arthritis, type 2 diabetes mellitus, or systemic lupus erythematosus.

Monounsaturated and polyunsaturated fatty acids are abundantly present in a diverse array of plant-based foods, while the latter are also critically found in marine-derived oils, particularly fish oils. The systematic table provided below offers a comprehensive inventory of food items serving as valuable sources of biologically significant fatty acids. We encourage further exploration of the health benefits associated with omega-3 fatty acids (α-linolenic acid ALA, eicosapentaenoic acid EPA, docosahexaenoic acid DHA), omega-6 fatty acids (linoleic acid LA, γ-linolenic acid GLA, arachidonic acid AA), and omega-9 fatty acids (oleic acid OA). **Key to abbreviations:** MUFA – sources of monounsaturated fatty acids PUFA – sources of polyunsaturated fatty acids **Foods rich in monounsaturated fatty acids (MUFA):** Plant-based oils: extra virgin olive oil, cold-pressed canola (rapeseed) oil, sunflower oil, corn oil, soybean oil, rice bran oil, peanut oil, sesame oil, evening primrose oil, pumpkin seed oil, sea buckthorn oil, hazelnut oil, almond oil, avocado oil. Other products: sunflower seeds, walnuts, hazelnuts, peanuts, almonds, pumpkin seeds, soybeans and soy-based products, black and green olives, sesame seeds, avocado pulp. **Foods rich in polyunsaturated fatty acids (PUFA, omega-3):** Oils: flaxseed oil (highest ALA content), canola oil. Other sources: flaxseeds, fatty marine fish (including Atlantic and Pacific salmon, mackerel, European sprat, sardines, Norwegian cod liver oil), shark liver oil. **Foods rich in polyunsaturated fatty acids (PUFA, omega-6):** Oils: flaxseed oil, wheat germ oil, sunflower oil, grapeseed oil, rice bran oil, evening primrose oil, walnut oil, pumpkin seed oil, canola oil, soybean oil, sesame oil, sea buckthorn oil, corn oil. Other sources: flaxseeds, sunflower seeds, pumpkin seeds, walnuts, soybeans and soy-derived products, sesame seeds. Unsaturated fatty acids play a pivotal role in maintaining optimal physiological function, exerting beneficial effects on lipid metabolism, inflammatory responses, and cognitive performance. Consequently, their deliberate inclusion in daily dietary patterns—while maintaining appropriate ratios between different fatty acid families (omega-3 to omega-6)—represents a cornerstone of preventive health strategies. Particular emphasis should be placed on the quality of dietary fats consumed, with a preference for plant-based oils (especially cold-pressed varieties) and fatty fish rich in long-chain omega-3 fatty acids. Additionally, we recommend reviewing information on phosphatidylcholine—a phospholipid of paramount importance for cellular membrane structure and lipid metabolism regulation.