Exam 1 Gastrointestinal Tract a tube through our body that food and beverages travel after consumptions Stomach o Holds food o Mechanical mixing and breaking food down o Gastric secretions o Absorption of alcohol and aspirin o Secretion of intrinsic factor important for B12 Small Intestine has a lining of finger like projections o 3 sections Duodenum Receives secretions from the liver pancreas and gallbladder Jejunum digestion and absorption continues here Ileum Absorption Enterohepatic circulation of bile o Gut and liver Folded into finger like projections called villi Villi then go to microvilli brush border Brush border where a lot of digestion occurs o Lining o Transport across the cell membrane but deficiencies can cause the body to not transport correctly o Types of transport Passive diffusion Facilitated transport Active Transport Endocytes Large Intestine o Smooth lining with no villi o Waste and electrolytes absorption o Intestinal microflora these are good healthy bacterial breakdown of fiber that produce Vit K and Biotin o Temporary storage and concentration until defecation Liver o Main storage site for Vitamins o Converts vitamins to metabolically active form o Metabolizes drugs alcohol and other toxins Metabolism of Vitamins and Minerals Nutrients 6 classes of Nutrients o Organic Carbs Fats Proteins and Vitamins no energy Vitamins discovery of vitamins came from deficiencies Organic contains Carbon Not energy yielding does not produce enery Essential cannot be made in the body o Vit K D Niacin can be made in body Water Soluble o Absorbed in portal blood and excreted through urine o Members of the B and C complex B1 Thiamin B2 Riboflavin B3 Niacin B5 Pantothenic acid B6 Pyroxidine B7 Biotin B9 Folate B12 Cobalamin o Inorganic Water and Minerals neither provide energy Fat Soluble Vitamins A D E K o Absorbed and transported closely with lipids o Micelle Enterocytes Chylomicrons lacteal o Stored in body lipids Vulnerable to destruction Can be destroyed by heat sunlight or cooking Cofactor non protein component of an active enzyme Coenzyme A vitamin loosely attached to an enzyme and influences enzymatic activity Prosthetic group vitamin bound tightly to an enzyme Minerals elements necessary for bodily functions which originates in the earth and cannot be made from living organisms and is obtained from plant animal and soil Macromineral these are minerals that are needed in larger quantities Inorganic and do not provide energy Essential Indestructible since it is an element found on periodic table o Ca Phosphorus K Mg Sodium Chloride Microminerals these are minerals that are needed in smaller quantities o Copper Zn Iodine Fluorine Selenium Fe Mn o Trace minerals Arsenic Nickel Si Va Cobalt Intake Recommendations o DRI recommendations to prevent chronic disease Has limits set for specific age groups and doesn t take metabolism activity level illness or nourishment status into account RDA the average daily amount of a nutrient considered adequate to meet the needs of most healthy people AI number set if there isn t sufficient data to set RDA o UL maximum amount of a nutrient that appears safe for a healthy person to consume Prevents toxicity diarrhea rebound scurvy o Assessment of intake Dietary food intake records and dietary recall Lab tests blood work and Hair analysis rare Physical outward signs symptoms Alcohol Metabolism Commonly associated with vitamin deficiency and metabolically treated like fat Dietary Guidelines Drink in moderation o Men no more than 2 drinks a day o Women No more than one drink a day o How is it made Liquid sugar yeast Yeast feeds on sugar to give off gas ethanol Final product non fermented sugar ethanol and liquid o 1 drink oz ethanol 12 oz beer 10 oz wine cooler 5 oz wine 1 5 oz 80 proof liquor 1 oz 100 proof liquor o 7 kcal for g of ethanol ETOH o How many g and kcal of ETOH in a 12 oz beer that is 5 ABV 8g mL x 05 ABV x 12 oz X 30 mL 14 4g 14 4g ETOH x 7kcal 100 8 kcal of ETOH o Alcohol Metabolism o Three systems mostly need to know the first 2 Alcohol dehydrogenase enzyme that converts alcohol into and aldehyde in gut and liver o Ethanol Acetylaldehyde Acetylaldehyde can bind to protein enzyme inhibiting functions Promotes fibrosis of liver Cirrbrosis Toxic o Retinol Retinal Vit A It is located in Gastric Mucosal cells stomach and mostly in liver The amount of this enzyme varies and women people of the Asian area tend to produce less of this enzyme So they tend to drunk faster because their stomach doesn t have much of this enzyme so the alcohol enters the blood and travels to the liver Requires NAD NADH Niacin B3 acts as a coenzyme Acetaldehyde Dehyrogenase Only in the hepatocells liver o Utilizes NAD NADH o Acetaldeyhyde Acetate Acetate 20 30 of acetate stays in the liver and then enters blood stream via VLDL and then other 70 80 enters the blood stream o The 70 80 that enters the blood stream causes a decrease signal of FA from adipose tissue causing FA to build up on liver o Also the 70 80 acetate enters muscle tissue to be oxidized as energy Acetate can then be converted to Acetyl CoA and go through De Nova FA synthesis So lets look at the big picture o Alcohol Acetaldehyde Acetate Enzyme 1 Alcohol Dehydrogenase Enzyme 2 Acetaldehyde Dehyrogenase Both require NAD o Problems Depletion of NAD Saturation of the enzymes more alcohol than enzymes Microsomal Ethanol Oxidizing system MEOS This alcohol metabolism occurs in the Smooth ER and works similar to the ETC It usually kicks in when Alcohol Dehydrogenase becomes totally saturated unless you are a heavy drinker it will automatically kick in It basically bypasses the Alcohol Dehydrogenase step from the pathway above Utilizes Riboflavin FAD FMN and Niacin NADPH Cytochrom P450 is involved End Products Water NADP Acetylaldehyde Increases the size and number of SER and Cytochrom P450 o This is how tolerance builds Also metabolizes xenobiotic drugs o Since the MEOS pathway also deals with drug metabolism alcohol can affect the metabolism of drugs Catalase not very important It can cause a greater tolerance OR toxicity o Metabolic Changes in response to ETOH Body slows other metabolic processes to metabolize alcohol Gluconeogenesis declines Utilizes H2O2 2 Ethanol hypoglycemia Protein synthesis decreases Krebs cycle slows FA synthesis increases Ketone body synthesis increases High NADH NAD ratio Pyruvate Lactate o Organ Specific GI Stomach increased HCL secretions Acetaldehyde is toxic
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