Chapter 8: Alcohol

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

Alcohol Absorption

Alcohol Metabolism

Small amounts metabolized by Alcohol dehydrogenase (ADH)Liver enzyme

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

microsomal ethanol-oxidizing

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

Alcohol and the Liver

Normal Liver Fatty Liver Cirrhotic Liver

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

Alcohol & Nutrients

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)?