chapter 8: alcohol alcohol the character of alcohol ethanol; the alcohol in beer, wine, spirits...
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AlcoholThe character of alcohol Ethanol; the alcohol in beer, wine, spirits
Properties No digestion Rapid absorption by simple diffusion Rate high in duodenum No cellular receptors required 5% leaves body in form of sweat, urine, or breath 95% remains in the body until oxidation Metabolized or chemically changed in liver
Is alcohol a nutrient?
Provides energy; 7 kcal/gramNo other nutritive valueEmpty caloriesNo vitamins, minerals, fat, or proteinLack nutrient density
Alcohol: Production
Malting
Fermentation: glucose converted to pyruvate
CHO---Maltose---Glucose ----Pyruvate --Acetaldehyde ------Ethanol
Ethanol processed in a variety of ways to alcohol
Metabolizing large amounts of alcohol
Overwhelm ADH, cannot keep up Uses microsomal ethanol-oxidizing system (MEOS) a back-up
system in liver MEOS used by liver to metabolize drugs Increase alcohol metabolism and tolerance
Pathway reduces body’s ability to detoxify drugs Increase potential for drug overdose Liver damage will hamper other metabolic pathways
Removing alcohol from circulation Liver metabolism limited Blood alcohol level falls slowly
CatalaseFound in the liver peroxisomes
Minor pathway for alcohol metabolism
Catalase
H2O2 H2O
Ethanol Acetaldehyde
Fate of Acetyl-CoA (from alcohol metabolism)
More like a fat than a CHO
CO2 + H2O
Acetyl-CoA Fatty Acid
GlucoseX
Factors affecting Alcohol Metabolism
Gender Women: smaller body size, less total body water; less ADH
activity in stomach (only 10% metabolized in stomach); more serious effects of chronic alcohol abuse;
More alcohol in blood liver cirrhosis is high Women are more likely to develop cirrhosis
Males High activity of ADH in stomach cells (Metabolize ~30% of
alcohol in stomach) Higher amount of body water
Age; race; size; food; physical condition; alcohol content
Benefits of Moderate Alcohol Intake (Table 8-3 )
1 drink a day for men, < 1 drink for women or 1 5oz glass of wine
Beer – no benefits
Red Wine Phytochemicals called polyphenols from grape skins
during processing Lower risk of CVD Lower risk of Ischemic stroke: lack of blood to brain
Effects of Alcohol
Alcohol cannot be stored and has priority in metabolism
Metabolized by the liver
Damages protein in cell membranes as it enters into cells
Liver cells-mostly affected May cause Cirrhosis of the liver
Effects of Alcohol:Cirrhosis
Fatty infiltration of the liverIncreased synthesis of fat from accelerated acetyl-CoA production
Enlarged fatty deposits choke off nutrient and O2 supply to liver cellsEngorged liver cells burst and dieScar tissue forms- process called cirrhosis50% chance of death within 4 yearsIs the second leading cause for a liver transplant
Liver DamageBuild-up of acetaldehyde can be toxic
Free radicals from alcohol metabolism destroy cell membranes & DNA: Alcohol inhibits body’s natural defenses
against free radicals
Advanced stages of liver damage are not reversible
Alcohol Abuse
3rd leading cause of death
Combined with tobacco, increases the risk of esophageal and oral cancer Risk for CVD Liver cirrhosis, damages cell membranes esp liver cells Fatty liver suicides fetal damage obesity Some forms of cancer osteoporosis, brain damage, impotence, sleep disturbance, etc.
Alcohol & NutrientsVitamin deficiencies Alcohol interferes with vitamin metabolism Folate, thiamin, vitamin B6, B12, C, vitamin A
Magnesium deficiency Increase magnesium loss via the urine Tetany—sharp contraction of muscles, twitches, cramps, seizures Impaired CNS Hallucinations
Zinc deficiency Decreased absorption and increased excretion Change in taste and smell, anorexia, trouble seeing at night, impaired wound
healing
Iron toxicity in liver, hasten cirrhosis, iron deficiency, due to GI bleeding.
Alcohol & Nutrients
Polyneuropathy A disease process that involves the peripheral nerves Can culminate in muscle paralysis, loss of sensation in lower extremities if
untreated Usually associated with deficiencies in thiamin (vit B)
Sideroblastic anemia Anemia characterized by RBC containing an internal ring of iron; due to
vitamin B6 deficiency
Megaloblastic anemia A form of anemia characterized by large, nucleated, immature red blood cells
that result from the inability of precursor cells to divide normally. Due to folate deficiency
Fetal Alcohol Syndrome
Alcohol reaches the fetus
Deprive brain of oxygen and nutrients
~4 drinks a day or binge drinking while pregnant
May cause Mental retardation Short attention span Hyperactivity Social and behavior problems Abnormally small at birth Small head circumference Small, widely spaced eyes Flat mid-face Thin upper lip and jaw underdeveloped
Alcohol Blood Levels and Brain Responses
Judgment impaired
Emotional control impaired
Muscle coordination, reflexes impaired
Vision impaired
Drunk, lacking control
In a stupor
Loss of consciousness, death
0.05
0.10
0.15
0.20
0.30
0.35
0.50—0.60
Brain ResponseBlood Level
Other Problems of Alcohol
Drinking in the workplaceOperating motor vehicles and equipmentSexually transmitted diseasesUnplanned pregnancyChildren of alcoholics are 4x more likely to become alcoholicsWarn children of the consequences of alcohol A low threshold to alcohol
Depression
Binge Drinking
Especially in college students
> 4 or more drinks in a row
Acute alcohol intoxication
Signs of alcohol poisoning semiconsciousness or unconsciousness slow respiration (<8 breathes per min. or more >8
seconds between breath) cold, clammy, pale, or bluish skin strong odor of alcohol
2005 Dietary GuidelinesAlcoholic Beverages
Those who choose to drink alcohol should do so sensibly and in moderation 1 drink/day for women 2 drinks/day for men
Alcoholic beverages should not be consumed by Those who cannot restrict intake Women of child bearing age Pregnant & lactating women Children & adolescents Those taking medications Those with specific medical conditions Those driving or operating a machine
Advice on page 273
U.S. Surgeon General’s office, the National Academy of Science, USDA/DHHS do not specifically recommend drinking alcohol
“Drink in moderation”
Avoid alcohol while pregnant
DiagnosisPhysiological dependence
Tolerance to the effect of alcohol
Evidence of alcohol-associated illnesses
Continued drinking in defiance of medical and social advise
Depression and blackouts
C.A.G.E. Questionnaire
C: Have you ever felt you ought to cut down on drinking?A: Have people annoyed you by criticizing your drinking?G: Have you ever felt bad or guilty about your drinking?E: Have you ever had a drink the first thing in the morning to steady your nerves or get rid of a hangover (eye-opener)?