Transcript Alcohol - McGraw

Perspectives in Nutrition
5th ed.
Gordon M.Wardlaw, PhD, RD, LD, CNSD
PowerPoint Presentation by
Dana Wu Wassmer, MS, RD
Chapter 8: Alcohol
Production of Alcohol
Anaerobic condition
Glucose
Pyruvate
Fermentation of yeast
Maltose
CO2
Acetaldehyde
NADH
NAD+
Amylase
CHO
Ethanol
Alcohol Absorption
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Depends on rate of stomach emptying
Intake of certain drugs
Type of beverage consumed
Moves easily through the cell
membranes
– Damage the cell membranes
– Liver cell damage
Alcohol (Ethanol) Metabolism
• Depends on gender, race, size, food,
physical condition, alcohol content
• Some ethanol are metabolized by the
stomach cells
• Majority of the ethanol is metabolized by
the liver
• Alcohol cannot be stored and has priority in
metabolism
Low Ethanol Intake-ADH
Pathway
• Occurs in the cytosol; yields energy
Alcohol dehydrogenase
Ethanol
NAD
ATP
Acetaldehyde
NADH
NAD
CoA
NADH
Acetyl-CoA
Citric Acid Cycle
High Ethanol Intake
• Microsomal ethanol oxidizing system
(MEOS) in the cytosol
• Uses energy
• Pathway reduces body’s ability to detoxify
drugs
• Liver damage will hamper other metabolic
pathways
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MEOS Pathway (Fig. 8-1)
MEOS Pathway
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Excessive alcohol intake
Occurs in the liver
ADH cannot keep up with demand
Used to metabolize drugs, foreign substances, and
alcohol
• Increase alcohol metabolism, thus, alcohol
tolerance
• Uses ATP in the process (leading to weight loss)
• Potential for drug overdose
Catalase
• Found in the liver
• Minor pathway for alcohol metabolism
Fate of Acetyl-CoA
Acetyl-CoA
X
CO2 + H2O
Fatty Acid
Glucose
Alcohol Abuse
• Contributes to the leading causes of death
• Combined with tobacco, increases the risk
for esophageal and oral cancer
• Risk for heart disease, nutritional
deficiencies, fetal damage, obesity, cancer
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Effects of Alcohol (Fig. 8-2)
Damage to the GI Tract
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Damage the cells
Overabsorption of iron
Malabsorption
Diarrhea and steatorrhea
Inflammation of the pancreas and gall
bladder
– Decrease enzyme production
– Decrease production of bile
– Difficulty digesting (and absorbing) nutrients
Effects on Water-Soluble
Vitamins
• Thiamin deficiency
– Polyneuropath
– Wernicke-Kersakoff syndrome
• Niacin deficiency
– Alcohol uses large amounts of NAD and NADP during
its metabolism
• Vitamin B-6 deficiency
– Deficient intake and possibly increase breakdown
– Leads to decrease in RBC and anemia
More Water-Soluble Vitamins
• Vitamin B-12
– Alcohol interferes with absorption
– Alcohol decreases output of trypsin
• Folate deficiency
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Inadequate intake
Reduced absorption due to mucosa damage
Much is excreted
Cells, villi decrease in number
• Vitamin C
– Decrease intake and/or altered liver metabolism
– Scurvy
Effects on Vitamin A
Vitamin A
• Deficient intake
• Inability of the liver to produce carrier protein
• Low stores, regardless of intake
• Increase degradation of vitamin A
• Reduce enzymes to digest fat, thus reduces
vitamin A absorption
• Impaired conversion of beta-carotene to retinoids
Effects on Vitamin D
• Inadequate intake
• Reduce enzymes to digest fat, thus reduces
vitamin D absorption
• Decrease activation of vitamin D with liver
damage
• May cause bone cell dysfunction, reduces bone
formation
• Compromises calcium and phosphorus
metabolism
Other Fat Soluble Vitamins
• Vitamin K
– Decrease absorption
– Damage intestinal bacteria
• Vitamin E
– Reduced pancreatic enzymes
Effects on Minerals
• Magnesium deficiency
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Increase magnesium loss via the urine
Tetany—sharp contraction of muscles
Impaired CNS
Hallucinations
• Zinc deficiency
– Decrease absorption and increased excretion
– Change in taste and smell, anorexia, trouble seeing at
night, impaired wound healing
• Iron deficiency and toxicity
– Injuries in the GI tract; increased uptake
Cirrhosis
Fatty infiltration of the liver
• Response to increased synthesis of fat from
accelerated acetyl-CoA production
• Enlarge fat cells chokes off nutrient and O2
supply to liver cells
• Engorged fat cells burst and die
• Scar tissue
• 50% chance of death within 4 years
Liver Damage
• Build-up of acetaldehyde
• Production of free radicals
• Alcohol inhibits body’s natural defenses
against free radicals
• Free radicals damage cell membranes and
DNA
Fetal Alcohol Syndrome
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Avoidable
Alcohol reaches the fetus
Deprive brain of oxygen and nutrients
~4 drinks a day or binge drinking while
pregnant
• Abstinence from alcohol is the best advice
Brain Damage
• Cognitive dysfunction and motor nerve
deficit
• Shrinks the brain
• Reduces oxygen and nutrients to the brain
• Alcohol is a powerful depressant
Cancer
• Acetaldehyde may promote cancer
• Damage nucleotides that are incorporated
into DNA
• Acetaldehyde is a carcinogenic
• Common cancers
– Mouth, pharynx. Larynx, esophagus, liver,
colon, rectum and breast cancer