Lecture 14: Alcohol Why Talk about Alcohol? Energy source Interferes with metabolism Interferes with nutrient absorption Promotes health problems Nutrition 150 Shallin Busch, Ph.D. Alcohol is a term used by chemists to describe a type of molecule. Consuming Alcohol in Moderation Proof = amount of alcohol in a serving 100 proof = 50% alcohol 80 proof = 40% alcohol Serving size Glycerol is the alcohol used to make triglycerides. Ethanol is the alcohol in beer, wine, and distilled liquor. In relation to your size
10 oz wine cooler 12oz beer 1 1/2 oz hard liquor (80 proof whiskey, gin, brandy, rum, vodka) 5 oz wine Each of these servings equals one drink. Digestion Absorption 20% absorbed by walls of stomach None necessary before absorption Stomach has alcohol dehydrogenase enzyme which facilitates the breakdown alcohol Can reach brain within a minute, especially if stomach is empty 10% NOT ABSOREBED Breathed out or in urine Rest of alcohol in body is absorbed by intestines Alcohol is absorbed before most other nutrients
Alcohol Metabolism Liver works to clear alcohol from blood before blood goes to rest of body Liver makes alcohol dehydrogenase which can digest alcohol Liver can process about 1/2oz of ethanol an hour Processing of alcohol happens before processing of fatty acids, so they build up in the liver (causing a fatty liver) Alcohol Metabolism Breaking down alcohol uses up lots of niacin and pantothenic acid (B vitamins) These vitamins can t be used for other reactions such as glycolysis, TCA cycle, and electron transport chain Excess Acetyl CoA gets made into fat Alcohol Metabolism in Liver Fat (triglycerides) Fatty Liver Alcohol (ethanol) NAD+ NADH + H + Alcohol dehydrogenase Acetaldehyde NAD + NADH + H + Acetaldehyde dehydrogenase Acetate CoA Fatty acids Acetyl CoA 1) Fatty acids are not processed by liver when it is metabolizing alcohol TCA Cycle 2) Alcohol gets turned into fatty acids NAD=niacin CoA=pantothenic acid
Fatty Liver Liver does not function properly Fat in liver interferes with distribution of oxygen and nutrients Reversible with abstinence from alcohol Can scar tissue (first leads to fibrosis, then cirrhosis) Alcohol and Blood Acidity Hydrogen ions (which usually go into the electron transport chain) build up and make blood acidic Low glucose levels leads to ketosis (makes blood more acidic) Lots of used niacin molecules promotes production of lactic acid, again making blood more acidic Alcohol and Proteins Alcohol alters amino acid and protein metabolism Liver deaminates amino acids and used them to make fat or ketones Leads to protein deficiency that will only stop when cease drinking alcohol For example, leads to weakened immune system due to slower production of proteins of the immune system Alcohol and Nutrients Energy content: 7kcal/g Heavy drinkers often get calories from alcohol instead of food Why is this a problem? Alcoholics tend to have poor diets
Alcohol Induced Deficiencies Minerals Calcium, Magnesium, Zinc, Iron Vitamins B Vitamins: folate, thiamine and B6 Fat-soluble vitamins: A, C, D, E, K Alcohol and Folate Alcoholism leads to folate deficiency Liver loses ability to retain folate Kidney increases excretion of folate Folate deficiency impairs functioning of digestive system Makes it harder to absorb folate from diet Is linked to heart disease and promotes colorectal cancer Other effects of Alcohol Acts as a diuretic Causes loss of water and electrolytes Numbered in order of occurrence Alcohol s Effects on the Brain 1) Frontal lobe: Alcohol interferes with judgment and reasoning Beer increases gastric acid secretion Higher risk of ulcers Effects on brain put one at higher risk for injuring self and others 2) Midbrain: Alcohol impairs speech and vision 3) Pons, Medulla oblongata: Alcohol affects voluntary muscle control and coordination. 4) Cerebellum: Alcohol affects respiration, heart rate, and consciousness.
Great information on: National Institute on Alcohol Abuse and Alcoholism Table H7-1 Page 245 http://www.niaaa.nih.gov/ Check out Alcohol Alerts Table H7-2 Page 245 Table H7-3 Page 246
Table H7-6 Page 248