In reality, which are healthier – plant or animal fats?

Plant-based lipids are distinguished by their high content of unsaturated fatty acids—both monounsaturated and polyunsaturated—particularly those belonging to the omega-6 (n-6) and omega-3 (n-3) families. Due to the human body’s inability to synthesize them *de novo*, **linoleic acid (LA, n-6)** and **alpha-linolenic acid (ALA, n-3)** are classified as **essential unsaturated fatty acids (EUFAs)**, necessitating their exclusive dietary acquisition. Primary sources of these compounds (beyond marine oils) include high-quality vegetable oils such as canola, flaxseed, soybean, corn, and olive oil. Robust epidemiological evidence demonstrates an inverse relationship between LA intake and low-density lipoprotein (LDL) cholesterol concentrations—commonly referred to as "bad cholesterol"—while concurrently elevating high-density lipoprotein (HDL) levels, thereby mitigating atherosclerotic risk. The metabolic conversion of LA is critically dependent on the enzyme **delta-6-desaturase**, whose activity may be compromised by factors including excessive saturated fat consumption, micronutrient deficiencies (zinc, magnesium), tobacco smoking, or chronic alcohol use. Impaired enzymatic function can lead to inefficient conversion of LA into **gamma-linolenic acid (GLA)**, a compound with putative anti-inflammatory properties. Furthermore, an imbalanced omega-6 to omega-3 ratio (frequently observed in Western diets at ratios as high as 20:1) promotes the overproduction of **arachidonic acid**, a pro-inflammatory eicosanoid precursor. Alpha-linolenic acid (ALA) serves as a biochemical precursor for the long-chain fatty acids **EPA** and **DHA**, whose daily supplementation (~1 g) has been linked to reduced triglyceride levels, improved platelet function, and attenuated inflammatory biomarkers. Rich dietary sources of ALA include flaxseed oil, walnuts, and chia seeds. Emerging research also suggests potential therapeutic benefits of omega-3 fatty acids in neurodegenerative disorders (dementia), autoimmune conditions (rheumatoid arthritis), and dermatological diseases (atopic dermatitis). However, industrial processes such as **partial hydrogenation** can induce the isomerization of *cis*-unsaturated fatty acids into *trans*-configured variants, which exhibit atherogenic properties akin to saturated fats. Consequently, consumers are advised to avoid products labeled as containing "partially hydrogenated vegetable oils" to preserve the cardiometabolic advantages of plant-derived lipids.

While animal fats do contain a proportion of unsaturated fatty acids, they primarily serve as the main dietary source of saturated fatty acids (NKT). Fish, however, represent an exception, as they are the most valuable source of omega-3 fatty acids, specifically EPA and DHA. Although saturated fats play essential roles in the body, endogenous synthesis fully meets the body’s requirements, eliminating the necessity for external supplementation. Nonetheless, foods rich in NKT also provide other critical nutrients, including calcium (from dairy products), zinc, and vitamin B12 (from meat). It is advisable, however, to opt for low-fat versions of these products, particularly due to the established link between excessive NKT intake and an elevated risk of cardiovascular diseases. Their contribution to the diet should not exceed 10% of total daily energy intake.

Resolving this dilemma proves remarkably straightforward from the standpoint of modern nutritional science. Experts unanimously emphasize that plant-based fats should constitute a staple component of daily nutrition, whereas animal fats—with the notable exception of fish-derived fats, whose consumption in the average Polish diet remains insufficient—should be minimized to the greatest possible extent. In accordance with the latest guidelines from the Institute of Food and Nutrition, fish should be consumed at least twice weekly. It is crucial to note that rapeseed oil, owing to its high smoke point, represents the optimal choice for high-temperature cooking methods such as frying, baking, or braising. Other vegetable oils, including rapeseed oil itself, are best suited for cold applications like salad dressings and should never be exposed to high heat. Additionally, oils intended for raw consumption must be cold-pressed (unrefined); it is important to distinguish that the term "cold-filtered" is not synonymous with "cold-pressed" and may be deliberately misleading, as the refining process strips the product of its most valuable nutritional, aromatic, and flavor compounds. While fats are indispensable in the diet, they possess an exceptionally high caloric density (9 kcal per gram), meaning their intake—even within a health-conscious framework—must be monitored, though not reduced below 20% of total dietary energy requirements. We also invite you to read our article on phosphatidylcholine, which plays a pivotal role in lipid metabolism!