Fatty Acids and Lipids Powerpoint Presentation

It is a Unit of Biochemistry for nurses studying B.Sc. Nursing

1. LIPIDS PRESENTED BY- MS. DISHA SINHA

2. Lipids - Definition • Diverse group of naturally occuring organic compounds that are hydrophobic or amphipathic (both phobic and philic regions) organic compounds. • Soluble in organic solvents like ether , insoluble in water for non-polar nature. • Functions as energy storage, structural components, and signaling molecules.

3. Lipids - Classification 1. Simple Lipids: are Esters of fatty acids with alcohols • Fats and Oils: Glycerol + fatty acids (e.g., butter, olive oil). • Waxes: Esters of long-chain fatty acids and alcohols (e.g., beeswax). 2. Complex Lipids: contain additional phosphate, carbohydrates, or proteins. • Phospholipids: Glycerophospholipids , Sphingophospholipids . • Glycolipids: Contain carbohydrate groups (e.g., cerebrosides ). • Lipoproteins: Lipids + proteins (e.g., HDL, LDL).

4. Lipids - Classification 3. Derived Lipids: Products after hydrolysis of simple or complex lipids • Free fatty acids, steroids, fat-soluble vitamins. 4. Steroids: specific 4-ring structure • Cholesterol: Precursor to bile salts and hormones. • Steroid Hormones: Cortisol, testosterone, estrogen. 5. Other Lipids: • Terpenes, Eicosanoids.

5. Properties and Functions of Lipids • Properties: 1. Hydrophobicity 2. H igh energy content about 9kcal/g 3. A mphipathicity (hydrophobic and phallic) • Functions: - Energy storage, structural components of membranes. - Insulation, signaling molecules, vitamin absorption.

6. Fatty Acids - Definition • Organic molecules comprise a hydrocarbon chain and a terminal carboxylic acid group (-COOH ). • Building blocks of lipids with roles in energy storage, cell membranes, and signaling . • Characterized by chain length, saturation level, and configuration (cis/trans).

7. Fatty Acids - Classification 1. Based on Chain Length: S hort C hain FAs - fewer than 6 carbon atoms M edium CFAs - 6-12 Carbon atoms L ong CFAs - 13-21 carbon atoms V ery L ong CFAs - 22 or more carbon atoms 2. Based on Saturation: Saturated (SFAs) - no double bond between carbon atoms and typically solid in room temperature (Ex.- steric acid) Unsaturated (MUFAs, with one double bond and PUFAs with two or more than two double bond)

8. 3. Based on Configuration: Cis - Hydrogen atoms attached to the double-bonded carbons are on the same side. Naturally occurring and beneficial for health. Trans - Hydrogen atoms attached to the double-bonded carbons are on opposite sides . Found in industrially processed fats; associated with negative health effects. 4. Based on Essentiality: Essential (EFAs) - Cannot be synthesized by the human body and must be obtained through diet. Non-Essential - Can be synthesized by the body.

9. 5. Based on Functional Groups: Straight-chain - no branching Branched - branching in Hydrocarbon chain Hydroxy - contains (-OH) group in the chain Cyclic - cyclic structure 6. Based on Source: Animal Plant Marine

10. Importance of Fatty Acids • Energy Source: Metabolized for energy. • Structural Role: Key components of cell membranes. • Signaling Molecules: Precursors to bioactive lipids. • Insulation and Protection: Found in adipose tissue.

11. MUFA(s) MUFAs are fatty acids that contain one double bond in their carbon chain. This single double bond prevents tight packing of the molecules, making them liquid at room temperature but solidify when chilled . Examples: Oleic Acid : Found abundantly in olive oil. Palmitoleic Acid : Found in macadamia nuts and sea buckthorn. Food Sources: Plant-based sources : Olive oil, canola oil, avocados, almonds, peanuts, cashews. Animal-based sources : Poultry fat, and certain fish oils.

12. Clinical Significance Cardiovascular Health : MUFAs can lower LDL , while maintaining or increasing HDL and associated with a reduced risk of CAD. Anti-Inflammatory Effects : Reduce markers of inflammation, such as CRP. Insulin Sensitivity : Improve glycemic control, especially in individuals with Type 2 Diabetes. Weight Management : MUFA-rich diets can promote Fullness and reduce overall calorie consumption, aiding in weight management. Cognitive Function : Some evidence suggests that diets rich in MUFAs support brain health and may lower the risk of neurodegenerative diseases.

13. PUFA(s) PUFAs have two or more double bonds in their carbon chain. This makes them more fluid and reactive than MUFAs . Types of PUFAs: Omega-3 Fatty Acids : Examples: Alpha- linolenic acid ( ALA) and docosahexaenoic acid (DHA). Found in fatty fish (salmon, mackerel), flaxseeds, chia seeds, walnuts, and algae. Omega-6 Fatty Acids : Examples: Linoleic acid (LA) and arachidonic acid (AA). Found in vegetable oils (soybean, corn, sunflower), nuts, and seeds.

14. Clinical Significance Omega-3 PUFAs : Cardio-protective Effects : Lower triglyceride levels, reduce blood pressure, and prevent arrhythmias. Anti-Inflammatory Properties : Reduce inflammation, benefiting autoimmune diseases like rheumatoid arthritis. Brain and Nervous System : Essential for brain development and function. DHA supports cognitive health and reduces the risk of Alzheimer’s disease. Prenatal and Infant Health : Crucial for fetal brain and retinal development during pregnancy and early infancy.

15. Cont. Omega-6 PUFAs : Necessary for normal growth and development. Help regulate metabolism, maintain skin health, and support immune function .

16. Aspect MUFA PUFA Structure One double bond Two or more double bonds Examples Oleic acid (olive oil) Omega-3 (DHA, EPA), Omega-6 (LA, AA) Stability More stable, less prone to oxidation Less stable, more prone to oxidation Health Benefits Cardiovascular and metabolic health Anti-inflammatory, brain, and eye health Food Sources Olive oil, avocados, nuts Fatty fish, flaxseeds, vegetable oils

17. EFA(s) Essential fatty acids are fats that the body cannot synthesize and must be obtained through the diet . They must be obtained through dietary sources. The two main EFAs are: 1. Alpha- linolenic acid (ALA) : An omega-3 fatty acid. 2. Linoleic acid (LA) : An omega-6 fatty acid.

18. Clinical Significance 1. Cell Membrane Integrity : EFAs are integral components of cell membranes, maintaining fluidity and structural integrity, which is critical for proper cellular function. 2. Neurological Health : EFAs, especially omega-3 derivatives like DHA (docosahexaenoic acid), are essential for brain development and cognitive function. They support neuronal growth, synaptic transmission, and overall brain health. 3.Cardiovascular Health : EFAs help regulate cholesterol levels, reduce triglycerides, and prevent arterial plaque buildup, lowering the risk of heart disease.

19. Cont. 4. Immune Function and Inflammation : It includes prostaglandins and leukotrienes. These molecules regulate immune responses and inflammation. 5. Skin and Hair Health : EFAs prevent dry skin and maintain skin elasticity. Deficiency can result in dermatitis and brittle hair . 6. Growth and Development : Particularly important in infants and children for normal growth, vision development, and brain maturation . 7. Deficiency Consequences : Symptoms include dry skin, delayed wound healing, hair loss, impaired immunity, and neurological issues.

20. TRANS FATTY ACIDS Trans fatty acids are unsaturated fats with at least one double bond in the trans configuration. These can be: Artificial/Industrial Trans Fats : Created by partially hydrogenating vegetable oils to make them more solid and shelf-stable. Natural Trans Fats : Present in small amounts in dairy and meat from ruminant animals, produced naturally in the gut of these animals.

21. Clinical Significance Cardiovascular Disease (CVD) : Adverse Lipid Profile : Increases LDL and decreases HDL. Plaque Formation : Promotes the formation of arterial plaques . Diabetes Risk : May impair insulin sensitivity, increasing the risk of type 2 diabetes. Obesity : Linked to increased abdominal fat deposition, which is associated with metabolic syndrome and related health issues. Systemic Inflammation : Contributes to chronic inflammatory diseases, including arthritis and inflammatory bowel disease. Reproductive Health : May negatively impact fertility in both men and women by altering hormonal balances. Public Health Impact : The harmful effects of industrial trans fats have led to significant public health interventions . Natural Trans Fats : Found in small amounts in ruminant products like milk and beef, these are considered less harmful and may even have potential health benefits, such as anti-cancer properties from conjugated linoleic acid (CLA).

22. Related Disorders Disruptions in lipid digestion, absorption, or metabolism can lead to various disorders: Malabsorption Syndromes Steatorrhea : Excess fat in stools due to impaired absorption (e.g., celiac disease, chronic pancreatitis). Bile Acid Deficiency : Results in incomplete lipid emulsification. Hyper- lipidemias Elevated levels of lipids in blood, associated with increased cardiovascular risk. Obesity Excessive lipid storage due to imbalance between lipid intake and energy expenditure. Fatty Liver Disease (Hepatic Steatosis) Accumulation of triglycerides in liver cells, caused by obesity, alcohol consumption, or metabolic syndrome .

23. Cont. Atherosclerosis Deposition of LDL cholesterol in arterial walls, leading to plaque formation and cardiovascular diseases. Ketosis/Ketoacidosis Excessive ketone body production in uncontrolled diabetes or prolonged fasting. Gallstones (Cholelithiasis) Precipitation of cholesterol in bile due to imbalance in bile composition. Inborn Errors of Metabolism Abetalipoproteinemia : Impaired formation of chylomicrons and VLDL. Lipoprotein Lipase Deficiency : Impaired clearance of chylomicrons and VLDL.

24. Cont. Carnitine- palmitoyl Transferase (CPT) Deficiency : a hereditary disease that prevents the body from using certain fats for energy. Zellweger’s syndrome ( Hepato -renal syndrome) : a rare, inherited disorder that affects infants and is usually fatal. It's characterized by a reduction or absence of functional peroxisomes in cells, which are organelles that play a key role in metabolizing fatty acids . Jamaican vomiting sickness: is an acute illness caused by the toxins, which are present in fruit of the  ackee tree.

25. Compounds formed from Cholesterol 1. Bile Acids and Bile Salts Function : Facilitate digestion and absorption of dietary fats by acting as emulsifying agents. Synthesis : Cholesterol is converted in the liver to primary bile acids, cholic acid and chenodeoxycholic acid . These acids are conjugated with glycine or taurine to form bile salts. Process : In the liver, cholesterol undergoes hydroxylation by enzymes. Bile acids are secreted into bile, stored in the gallbladder, and released into the intestine during digestion. Recycling : Most bile acids are reabsorbed in the ileum and returned to the liver (enterohepatic circulation).

26. Cont. 2. Steroid Hormones: Steroid hormones are synthesized in the adrenal cortex, gonads, and placenta from cholesterol through the steroidogenesis pathway. Major Classes of Steroid Hormones : Glucocorticoids (e.g., cortisol ): Regulate metabolism, immune response, and stress. Synthesized in the adrenal cortex. Mineralocorticoids (e.g., aldosterone ): Maintain salt and water balance by acting on the kidneys. Sex Hormones : Androgens (e.g., testosterone ): Regulate male characteristics and reproduction. Estrogens (e.g., estradiol ): Regulate female characteristics and reproduction. Progestogens (e.g., progesterone ): Prepare the uterus for pregnancy and maintain pregnancy. Synthesis : The first step in steroidogenesis is the conversion of cholesterol to pregnenolone by the enzyme CYP11A1 , which is precursor for all Steroid Hormones.

27. Cont. 3. Vitamin D Cholesterol is the precursor for the synthesis of vitamin D. Synthesis : 7-Dehydrocholesterol, a derivative of cholesterol in the skin, is converted to cholecalciferol (Vitamin D3) upon exposure to ultraviolet (UV) radiation. Cholecalciferol is hydroxylated in the liver to form 25-hydroxyvitamin D3 , and then in the kidneys to form the active hormone 1,25-dihydroxyvitamin D3 (calcitriol ) . 4. Cell Membrane Components Cholesterol is a fundamental structural component of animal cell membranes. It contributes to membrane fluidity and integrity, ensuring proper function and stability of membrane-bound proteins.

28. Cont. 5. Lipoproteins: Cholesterol is a component of lipoproteins (e.g., LDL, HDL) that transport lipids in the bloodstream. LDL (Low-Density Lipoprotein ) : Delivers cholesterol to peripheral tissues. HDL (High-Density Lipoprotein ) : Transports cholesterol from peripheral tissues back to the liver (reverse cholesterol transport ). 6. Cholesterol Esters Cholesterol is converted into cholesterol esters for storage or transport. Enzyme : Acyl-CoA cholesterol acyltransferase (ACAT) catalyzes the esterification of cholesterol.

29. Cont. 7. Oxysterols: Oxysterols are oxidized derivatives of cholesterol. Function : Regulate cholesterol homeostasis and bile acid synthesis. Act signaling molecules. 8. Dolichols: Dolichols are long-chain poly-isoprenoid alcohols derived from cholesterol. Function : Participate in glycoprotein synthesis by acting as carriers for oligosaccharide chains in the endoplasmic reticulum . 9. Neuro-steroids: are synthesized from cholesterol in the brain. Function : Modulate neuronal activity and synaptic function by acting on neurotransmitter receptors like GABA-A.

30. Ketone Bodies Ketone bodies are three water-soluble compounds produced in the liver during the breakdown of fatty acids and ketogenic amino acids. They are synthesized as an alternative energy source, particularly during periods of low carbohydrate availability (e.g., fasting, prolonged exercise, or ketogenic diets).

31. Types of Ketone bodies The three primary ketone bodies are: Acetoacetate ( AcAc ) The first ketone body formed during ketogenesis in the liver. Acts as a precursor for the synthesis of the other two ketone bodies. Beta- Hydroxybutyrate (BHB) A reduced form of acetoacetate, formed by the enzyme beta- hydroxybutyrate dehydrogenase . It is the most abundant ketone body in the bloodstream and serves as a major energy carrier during ketosis. Acetone Formed by the spontaneous decarboxylation of acetoacetate. Volatile and excreted primarily through the lungs, giving a characteristic fruity odor to the breath of individuals in ketosis.

32. Significance 1. Alternative Energy Source Ketone bodies are crucial during periods of glucose scarcity (e.g., fasting, starvation). They provide energy to tissues such as: Brain : Ketone bodies can cross the blood-brain barrier and serve as an energy source when glucose availability is low. Skeletal Muscles and Heart : Ketone bodies are readily oxidized to generate ATP 2. Sparing Muscle Protein By providing an alternative energy source, ketone bodies reduce the need for gluconeogenesis, thereby sparing muscle protein from being broken down.

33. Cont. 3. Ketosis vs. Ketoacidosis Ketosis : A physiological state characterized by increased ketone body production, typically seen during fasting or a ketogenic diet. It is a normal adaptive response. Ketoacidosis : A pathological condition (e.g., diabetic ketoacidosis) marked by excessive ketone body production, leading to metabolic acidosis. It is potentially life-threatening . 4. Regulation of Metabolism Ketone bodies influence metabolic pathways and hormonal responses, such as enhancing insulin sensitivity and reducing appetite.

34. Cont. 5. Therapeutic Significance Epilepsy : Ketogenic diets, which promote ketone body production, are used to manage drug-resistant epilepsy. Neurodegenerative Diseases : Ketone bodies may have protective effects in conditions like Alzheimer's and Parkinson's diseases . 6. Indicator of Metabolic State Elevated levels of ketone bodies can indicate metabolic states like fasting, diabetes, or adherence to a ketogenic diet.

35. Lipoproteins Lipoproteins are macromolecular complexes that transport lipids through the aqueous environment of blood. Lipids , being hydrophobic, require these carriers to move efficiently between tissues. Lipoproteins are composed of a lipid core surrounded by a shell of phospholipids, cholesterol, and apo -lipoproteins .

36. Types 1. Chylomicrons Density : Lowest density lipoproteins (largest size). Composition : High triglyceride content, low protein . 2. Very-Low-Density Lipoproteins (VLDL ) Density : Slightly denser than chylomicrons. Composition : Rich in triglycerides, with some cholesterol and proteins . 3. Intermediate-Density Lipoproteins (IDL ) Density : Intermediate between VLDL and LDL. Composition : Contains triglycerides and cholesterol .

37. Cont. 4. Low-Density Lipoproteins (LDL) Density : Higher density than VLDL and IDL. Composition : Cholesterol-rich, low triglyceride content 5. High-Density Lipoproteins (HDL ) Density : Highest density due to high protein content. Composition : Rich in proteins, low in triglycerides and cholesterol.

38. Functions 1. Chylomicrons Transport dietary triglycerides, cholesterol, and fat-soluble vitamins (e.g., A, D, E, K) from the intestines to tissues for storage or energy production. Deliver remnants to the liver for recycling. 2. VLDL Transports triglycerides synthesized by the liver to peripheral tissues. Provides energy or storage in adipose tissue after triglyceride hydrolysis. 3. IDL Acts as a transitional particle in the conversion of VLDL to LDL. Delivers triglycerides and cholesterol to tissues or returns to the liver.

39. Cont. 4. LDL Primary transporter of cholesterol to cells for Cell membrane synthesis, Steroid hormone production, Bile acid synthesis. Excess LDL deposition in arterial walls contributes to plaque formation and atherosclerosis. 5. HDL Removes excess cholesterol from peripheral tissues and macrophages. Delivers cholesterol to the liver for excretion via bile (reverse cholesterol transport). Provides apo -lipoproteins to other lipoproteins, assisting their metabolism

40. Lipid Profile A lipid profile (or lipid panel) is a blood test that measures the levels of specific lipids (fats) in the blood. It is a diagnostic tool commonly used to evaluate cardiovascular health and to assess the risk of conditions such as heart disease, atherosclerosis, and metabolic syndrome.

41. Components 1. Total Cholesterol ( TC) : Represents the total amount of cholesterol in the blood, including cholesterol carried by all lipoproteins (LDL, HDL, and VLDL). Normal Range : Typically less than 200 mg/ dL . 2. Low-Density Lipoprotein Cholesterol ( LDL-C) : The amount of cholesterol carried by LDL, often referred to as "bad cholesterol." Normal Range : Optimal : Less than 100 mg/ dL . Borderline high : 130–159 mg/ dL . High : 160 mg/ dL or higher.

42. Cont. 3. High-Density Lipoprotein Cholesterol ( HDL-C): The amount of cholesterol carried by HDL, often referred to as "good cholesterol." Normal Range : Men : Greater than 40 mg/ dL . Women : Greater than 50 mg/ dL . 4. Triglycerides ( TG) : The most common type of fat in the body, stored in adipose tissue and used as an energy source. Normal Range : Optimal : Less than 150 mg/ dL . Borderline high : 150–199 mg/ dL . High : 200 mg/ dL or higher.

43. Cont. 5. Very-Low-Density Lipoprotein Cholesterol ( VLDL-C) : A type of lipoprotein that carries triglycerides and cholesterol. Normal Range : Estimated as 10–30 mg/ dL . 6. Non-HDL Cholesterol : Total cholesterol minus HDL-C; represents all "bad cholesterol" types (e.g., LDL, VLDL, IDL). Normal Range : Less than 130 mg/ dL . 7. Total Cholesterol/HDL Ratio : A ratio calculated to assess the balance between total cholesterol and protective HDL cholesterol. Normal Range : Less than 4:1 is considered desirable.

44. Purpose of Lipid Profile 1. Screening for Cardiovascular Risk Identifies individuals at risk of heart attack, stroke, and atherosclerosis. 2. Monitoring Treatment Evaluates the effectiveness of lipid-lowering therapies (e.g., statins, fibrates). 3. Diagnosing Metabolic Disorders Helps identify conditions like dyslipidemia , metabolic syndrome, and familial hypercholesterolemia. 4. Assessing Secondary Conditions Lipid abnormalities linked to diabetes, thyroid disorders, liver diseases, and kidney disease.

45. Atherosclerosis Atherosclerosis is a chronic, progressive disease of the arteries characterized by the buildup of fatty deposits, cholesterol, and other substances (collectively known as plaques) on the inner walls of arteries. This condition leads to the narrowing, hardening, and reduced elasticity of arteries, impairing blood flow and increasing the risk of cardiovascular complications.

46. Common Sites Coronary arteries: leading to coronary artery disease. Carotid arteries: risk of stroke. Peripheral arteries: causing peripheral artery disease. Renal arteries: leading to kidney dysfunction.

47. Risk Factors 1. Non-Modifiable : Age, male sex, family history of cardiovascular diseases. 2. Modifiable : High LDL ("bad cholesterol") and low HDL ("good cholesterol"). Hypertension, diabetes, obesity, smoking, sedentary lifestyle. Poor diet (high in saturated fats and trans fats).

48. Prevention and M/M Lifestyle Changes : Healthy diet, regular exercise, smoking cessation, weight control. Medications : Statins, anti- hypertensives , and diabetes control drugs. Surgical Interventions : Angioplasty, stent placement, or bypass surgery for severe cases.