Lipid Metabolism I, Part I

As seen in the failed attempts to utilize 2-AG endocannabinoid neurotransmitter signaling pathway as an obesity medication, what preliminary ideas does this hint at as you learn about the intricate design of nutrient digestion, regulation?

2-AG endocannabinoid NT: de-regulation of endocannabinoid signaling can contribute to obesity, behavioral, and mental disorders, hypertension, and atherosclerosis. CB1 Blockers reduce caloric intake and body weight. Us ein treatments was suspended due to behavioral side effects.

What are the main sources of fatty acids from western diets? (feel free to answer this question from a culturally relevant perspective)

Animal- Based sources of Fatty acids: - Red meat, Diary products, shortening, processed meats, poultry, fatty fish Plant-based sources of fatty acids: - Cooking oils, nuts and seeds, avocado, processed and fast foods. Baked Goods and Desserts *bold: Main sources of Fatty Acids from wester diets. Up to 10g of daily fatty acid intake in some western countries are trans fatty acids (US = 1.5-2g/day) Linoleic and a-linoleic acid are essential fatty acids that are not produced by the body need to get it from food.

What are lipids, and their functional classifications of lipids?

Bile acids: Steroids that aid in fat digestion and nutrient absorption. Cholesterol: Component of cell membranes; precursor of other steroids Eicosanoids: Fat-soluble vitamins (A,D,E,K): Chemical messenger between cells Fatty acids: involved in a variety of functions including blood clotting, wound healing, vision, and calcium absorption. Phospholipids: Major component of cell membranes; aid in fat digestion Steroid hormones: Chemical messengers between cells Triglycerides: Energy storage; thermal insulation; filling space; binding organs together; cushioning organs - 90-95% Functional Classification of Lipids: - Neutral lipids (non-membrane, simple lipids): o Fatty acids o Mono-, di-, triacylglycerols (or -glycerides): § All water needed to sustain life is provided fromt eh metabolism of triglycerides. § Functions of triglycerides: · Energy storage, energy transport and thermal insulation and protection. o Sterol esters (cholesterol esters) - Polar lipids (membrane, complex lipids) o Phospholipids § Glycerophospholipids (backbone is glycerol) § Sphingolipids (backbone is sphingosine) o Cholesterol

Why might knowing the nomenclature of fatty acids be relevant to clinical practice and biomedical research?

Carboxyl carbon is #1, or alpha (a) carbon Methyl carbon, #18 in the picture (or n) or omega (w) carbon Ex: Saturated Fatty Acids: Stearic Acid: C18:0 Number of carbons: number of double bonds) Unsaturated Fatty Acid: Oleic Acid: C18: 1w9 (counting from w (or n) carbon) or c18Delta9 (counting from a carbon). PUFA cannot change families: "once omega-6, always omega-6" a. Fatty acids are generally identifiable by the group on their alpha carbon. b. What distinguishes a cis from a trans bond in a fatty acid and why is this important to know.

Give examples of Fats in their concentrated, unprocessed and supplement form?

Concentrated fats: - Vegetable oils: corn, olive, palm, sunflower, etc. - Animal Fats: Tallow, lard, fish oil, and butter - Commercial products: margarines, spreads. Unprocessed Fats: - Meats - Eggs, milk, and dairy products - Legumes, grains, nuts, seeds, oily vegetables Dietary supplements: - Oils, vitamins, etc.

How much energy can be derived from the most concentrated source of fat?

Dietary fats (triglycerides) are the most concentrated source of energy (9Kcal/gram)

What are the four types/categories of fatty acids in food of both animal and plant origin? What are their differentiating characteristics? Describe their properties at room Temperature? Describe their health implications?

Fats (solids) and oils (liquid fats) of animal and plant origin consist mostly of: - Triacylglycerols (triglycerides), 90-95% of all fats in foods plants - Phospholipids (mainly phosphatidylcholine, aka lecithin) - AchSterols: cholesterol (animal foods), phytosterols (plant foods). - Fat-soluble vitamins (A, D, E, K) and vitamin precursors (carotenoids) a) Saturated: No double bond, straight structure, solid at room temperature. b) Trans: One or more 2x bonds in trans configuration, straight structure, semi-solid/ solid at room temperature c) Monounsaturated: one 2x bond in cis configuration, bent structure, liquid at room temperature d) Polyunsaturated: Multiple 2x bonds, in cis configuration, even more bent in structure, liquid at room temperature Trans configuration - shelf life; easy to transport ex: butter, tallow

What are the two essential fatty acids? Why are they classified as essential?

Fats in foods carry the essential fatty acids: - Linoleic acid (omega-6-fatty acid) - A-linolenic acid (omega-3- fatty acid) Essential fat-soluble vitamins (ADEK vitamins), and phytochemicals These fatty acids are classified as essential because the human body cannot synthesize them and must obtain them form the diet. They are essential for various physiological functions. Including cell membrane structure, inflammation regulation, and the production of other fatty acids.

What makes a fatty acid saturated vs unsaturated?

Fatty acids are carboxylic acids with hydrocarbon chains. - From 4-36 carbons long. Few contain three-carbon rings, hydroxyl groups, or methyl group branches. Saturated Fatty Acids: no double bonds in their hydrocarbon chains, which makes them saturated with hydrogen atoms. Typically solid at room temp. Found in animal products like meat and dairy and in some plan oils like coconut oil Unsaturated Fatty Acids: one or more double bonds in their hydrocarbon chains, creating kinks in the chain and making them less tightly packed. Results in liquid (oil) form at room temp. Found in plant oil, fatty fish, and nuts.

Describe the main properties of lipids, their organization, and their interactions in water

Lipids are molecules that are soluble in organic (nonpolar) solvents (hexane, chloroform, methanol) and weakly soluble in water. Lipids can organize in large, supramolecular structures through non-covalent interactions (membranes, lipid droplets, lipoproteins)

What are the classifications of lipoproteins?

Lipoproteins are classified based on their density, composition, and function. The main classes of lipoproteins include: - Chylomicrons: largest and least dense lipoproteins and are primarily involved in transporting dietary triglycerides from the intestines to carious tissues. - VLDL (Very Low-Density Lipoproteins): Synthesized in the liver and transport triglycerides to peripheral tissues. Intermediate in size and density. BAD// Very low density - LDL (Low density lipoprotein): "Bad cholesterol". Smaller and denser and transport cholesterol from the liver to peripheral tissues. Elevated LDL levels are associated with an increased risk of atherosclerosis. BAD // Low density - HDL (High Density Lipoproteins): "Good Cholesterol" smallest and denser lipoproteins and play a role in removing excess cholesterol from tissues and transporting it back to the liver for excretion. GOOD // high density

What is the function of lipoproteins in the body and what are they classified by?

Lipoproteins are macromolecules complexes that transport lipids, including cholesterol and triglycerides through the bloodstream. They serve several important functions in the body: - Transport of Lipids, Energy Delivery, cholesterol distribution, metabolic regulation, transport of fat-soluble nutrients

What is a common redundancy in the advertising of trans-fat free plant foods?

Many plant-based foods naturally do not contain trans fats, so advertising them as "trans-fat free" is redundant statement. Trans fats are primarily found in hydrogenated or partially hydrogenated oils, which are typically using in processed and fast foods. Whole plant foods like fruits, vegetables, grains, and legumes do not undergo hydrogenation processes and are naturally trans-fat free.

DAG and PA exhibit what dual functions?

Monoacylglycerol (MAG), Diacylglycerol (DAG), Phosphatidic acid (PA) DAG and PA exhibit dual functions: - Precursors in the synthesis and breakdown of triacylglycerol's and phospholipids - Messengers in signaling cascades. Glycerol +1 Fatty Acid = MAG Glycerol + 2 Fatty Acids= DAG DAG + phosphate = PA

Notes

Notes: Membrane Lipids: Phospholipids: - Glycerophospholipids o Phospholipids are amphipathic molecules with nonpolar "tails" and a polar or charged "head group" o Glycerol +2 Fatty acids + phosphate + head group - Sphingolipids: sphingosine instead of glycerol o Constituents of biological membranes o Derived from c-18 amino alcohols sphingosine and dihydrosphingosine o One sphingolipid will decide the blood type (recognition system) - Functions of phospholipid as components of membranes o Selective permeability barrier o Molecular receptors/ transducers (signal transduction systems) o Support and regulate carrier/transport systems. Cholesterol and Cholesterylesters: - Structure: 4-ring core structure: cyclopentanoperhydrophenanthrene, or steroid nucleus. o Sterols are monohydroxy alcohols of steroidal structure. - Cholesterol: important get from animals o Cholesterol in adrenal glands cortisol: corticosteroid hormones o Cholesterol in liver Bile acids o Cholesterol in sex glands progesterone testosterone Estradiol Sex hormones, o Cholesterol UV light vitamin D3 - Cholesterol derivatives: functions: o Biological and physiological functions: § Free cholesterol: membrane structure and dynamics § Cholesterylesters: lipid storage and lipoproteins § Bile salts: lipid digestion and absorption § Steroid hormones: development and function of reproductive organs, development of secondary sex characteristics, control of macronutrient and mineral metabolism § Vitamin D synthesis: calcium homeostasis, bone growth, transcriptional control, etc.

Fat is not intrinsically bad, but in excess can lead to ___ and in its storage dysfunction can lead to___.

Obesity Type 2 Diabetes, cardiovascular disease Lipodystrophy: uneven distribution fat in your body anorexia, fatty liver disease

What are the factors that influence the solubility of fatty acids?

Polarity: more polar the less soluble it is in nonpolar solvents like oil. Saturated fats are less polar and less soluble in water Chain length: longer fatty acid chains are less soluble in water than shorter ones bc. Of hydrophobic tail Saturation: saturated less soluble than unsaturated bc straight and densely packed structure minimizes their contact with water. Temperature: change from liquid, gas, and solid. Degree of hydrogenation: artificially saturated, unsaturated fats are less soluble in water than their unsaturated counterparts

What benefits might there be to consuming more fats in unprocessed foods compared to in their concentrated form?

Unprocessed foods contain a broader range of nutrients including vitamins, minerals, and dietary fiber. The fats in unprocessed foods are often accompanied by beneficial compounds, such as antioxidants in nuts and polyphenols in olive oil. Unprocessed foods are generally associated with better overall dietary patterns and may contribute to improved health outcomes when part of a balanced diet.