NUTR 8030 Exam 1

• Conditionally essential - certain diseases that cause certain AA to become essential (body can’t synthesize them).
• GI system consists of main organs that touch the food (mouth → anus) and accessory organs that aid in chemical digestion or create an environment for breakdown (i.e pH).
• PU fats include walnuts, vegetable oils, fish; low fat excludes f/v/grains.
• Linoleic and a-linolenic are the major polyunsaturated fatty acids.
• MU fats include olive oil, nuts, avocado, meats, and pb.
• Palmitic acid (C16:0) is the major saturated fatty acid.
• Oleic acid (18:1n-9) is the major monounsaturated fatty acid.
• GI tract anatomy consists of the lumen (hollow center of GI), mucosa (epithelium that creates mucosal barrier), lamina propria (connective tissue that contains blood vessels, lymphatic vessels, nerve fibers, lymphoid tissue (immune), exo-/endocrine glands), muscularis mucosa (contains smooth muscle (involuntary)), submucosa (houses enteric nervous system), Meissner’s (submucosal) plexus (stimulate cells in mucosa to do things, larger blood & lymph vessels facilitate transport), muscularis externa (houses muscles), circular muscle, Auerbach’s (myenteric) plexus (can receive signals from both p
• Intrinsic Enteric nervous system (ENS) is a “second brain” located between submucosa and muscularis externa, extends from esophagus → anus, consists of > 100 mill neurons, is mostly cholinergic neurons (stimulated by acetylcholine), protects, acts on intestine for GI motility/secretion.
• Meissner’s plexus innervates cells in mucosa for GI secretions.
• Auerbach’s plexus innervates muscularis externa for food movement (i.e peristalsis).
• Afferent (gut → brain) and efferent (brain → intestine) pathways exist in the nervous system.
• Chewing and mixing of food with saliva are mechanical digestion, while peristalsis is a chemical digestion.
• The Autonomic Nervous System (ANS) consists of the Peripheral Nervous System (PNS) and the Central Nervous System (CNS), with the PNS carrying messages to and from the CNS.
• The Parasympathetic Nervous System (PSNS) calms the body to conserve and maintain energy, while the Sympathetic Nervous System (SNS) arouses the body to expend energy.
• FA classification includes chain length (<6C, 6-12C, >12C), double bonds (saturated (0), monoun. (1), polyun (2+)), and double bond geometry (usually cis, but in PUFAs typically methylene bridge in between).
• Dietary sources of unsaturated fats include vegetable oils like canola, soybean, corn, sunflower, olive, sesame, safflower, walnut, pumpkin, flaxseed, avocado, and nuts like almonds, cashews, hazelnuts, walnuts, pecans, macadamias, and pistachios.
• Unsaturated fats - vegetable oils like canola, soybean, corn, sunflower, olive, sesame, safflower, walnut, pumpkin, flaxseed, avocado, and nuts like almonds, cashews, hazelnuts, walnuts, pecans, macadamias, and pistachios.
• The Myenteric Plexus inhibits the digestive/absorptive process, while the Auerbach’s Plexus can receive signals from both para-/sympathetic systems.
• No RDA for total fat, but AIs for linoleic and a-linolenic acid.
• Recommended intake for saturated fat is <10% and for trans fats is 0%.
• Dietary sources of saturated fats include animal products like butter, cheese, donuts, cakes, fatty meats.
• Dietary fats and lipids are both plant and animal source foods (except cholesterol) and are a major energy source (9 kcals).
• Major functions of lipids include structure for cell membrane (phospholipids/cholesterol), precursor for steroid hormones (cholesterol), form of energy storage (triacylglycerols), lubrication for body surfaces (phospholipids), signaling molecules (phospholipids/eicosanoids), electrical insulators (phospholipids/sphingomyelin), biological detergents (bile acids), and membrane anchors for proteins (phospholipids).
• Essential fatty acids include linoleic (n-6) and a-linolenic (n-3), which are sources of fat-soluble vitamins, antioxidants, and bioactive compounds.
• Triacylglycerol (TAG) is the most abundant dietary lipid, with approximately 70-100 g/day.
• AMDR for total fat is 20-35% total calories.
• Lipids help in the absorption of fat-soluble vitamins.
• Pyruvate kinase converts phosphoenolpyruvate (PEP) to pyruvate, marking the end of glycolysis.
• Hepatic glycogen synthesis dominates at high plasma glucose concentration.
• Feeding causes dephosphorylation, activation of glycogen synthase, and is promoted by insulin in the liver.
• Glycogen synthesis is regulated via covalent mods, allosteric effectors, and the size of glycogen molecule.
• Fasting causes phosphorylation, inhibition, and is promoted by glucagon or catecholamines that signal via cAMP activation of PKA.
• Fructose is metabolized in the liver, with most of the dietary fructose absorbed into portal blood being removed by the liver.
• Hexokinase/glucokinase converts glucose to glucose-6-phosphate, trapping glucose in cells and activating it for further metabolism.
• Galactose is mostly derived from the digestion of lactose and is taken up by the liver via GLUT2, where it is metabolized to form G1P.
• Glycogen synthase catalyzes the addition of glucose units, and glycogen branching enzyme generates the branching structure.
• Glycolysis occurs in all cell types.
• In the liver, citrate is converted to palmitate, producing extra fats for bodily use.
• Hexokinase is inhibited by G6P.