Fatty acids
๐ฅฉ Fatty acids are long-chain carboxylic acids that act as the bodyโs major energy source, building blocks of membranes ๐งฑ, and precursors for signaling molecules ๐ก. Their structure and metabolism influence both health and disease.
๐ Key Concepts
- Types of Fatty Acids:
- ๐ง Saturated (no double bonds) โ solid at room temp. Found in butter, lard, animal fats. โ LDL, โ CV risk.
- ๐ฅ Unsaturated (โฅ1 double bond):
- Monounsaturated (MUFA): e.g., Oleic acid in olive oil โ cardioprotective โค๏ธ.
- Polyunsaturated (PUFA): e.g., Linoleic (ฮฉ-6), ฮฑ-linolenic (ฮฉ-3). Found in nuts, fish oil ๐.
- ๐ Trans fats (hydrogenated oils) โ unnatural configuration, linked to atherosclerosis & metabolic disease โ.
- Essential Fatty Acids (must come from diet):
- Omega-3 (ALA, EPA, DHA) โ ๐ง brain, retina, anti-inflammatory.
- Omega-6 (linoleic acid) โ pro-inflammatory mediators โก.
โ๏ธ Functions of Fatty Acids
- ๐ฅ Energy: ฮฒ-oxidation in mitochondria โ acetyl-CoA โ Krebs + ETC โ ATP.
- ๐งฑ Structural: Incorporated into phospholipids โ control membrane fluidity & signaling platforms.
- ๐ก Signaling: Precursors for eicosanoids (prostaglandins, leukotrienes, thromboxanes).
- ๐ก๏ธ Protection: Stored in adipose โ insulation + shock absorption.
๐ Metabolism
- ฮฒ-Oxidation (mitochondria) โ FA โ acetyl-CoA + NADH + FADHโ โ ATP.
- Ketogenesis (liver, fasting/starvation) โ acetyl-CoA โ ketone bodies (acetoacetate, ฮฒ-hydroxybutyrate, acetone). Fuel for ๐ง brain & ๐ซ heart.
- Fatty Acid Synthesis (cytoplasm) โ Acetyl-CoA โ Malonyl-CoA โ Palmitate (16C). Uses NADPH (from PPP & malic enzyme).
๐ฉบ Clinical Relevance
- โค๏ธ Cardiovascular: High saturated/trans fats โ โ LDL, atheroma. Omega-3 โ triglycerides, stabilises plaques.
- โ๏ธ Obesity: Excess fat storage โ metabolic syndrome, insulin resistance.
- ๐ฉธ Diabetes: Altered lipid metabolism โ โ lipotoxicity, impaired insulin signalling.
- ๐ฅ Inflammation: ฮฉ-6 eicosanoids = pro-inflammatory; ฮฉ-3 = anti-inflammatory balance.
- ๐ง Neurology: DHA crucial for synapse function, retina development. Deficiency โ cognitive decline.
๐ Quick Summary
๐ง Saturated = Solid, โ LDL.
๐ฅ Unsaturated = Healthy, โ membrane fluidity.
๐ Omega-3 = anti-inflammatory, neuroprotective.
๐ฅ ฮฒ-oxidation = ATP; ๐ง fasting = ketones.
โค๏ธ Clinical: Trans fats โ atheroma, Omega-3 โ CV protection.
