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Alcohol
“Beer is proof that god loves us and
wants us to be happy.”
-Benjamin Franklin
History of alcohol
• Old religious and medical writings frequently
recommended its use
• Lifts spirits, ease boredom, numb hunger, dull
discomfort
• People value alcohol for its analgesic
and euphoric qualities
History of Alcohol
• 6400 BC: Neolithic people produced berry
wines
• 4000 BC: Sumerians fermented grains and
cereals, producing beer, date wine and other
alcoholic beverages
• Ancient Egyptians recorded >100 medical
prescriptions for alcohol
• Babylonians developed >20 different types of
beer
Alcohol: definition
• Organic compound with one or more –OH groups
• The alcohol found in beer, wine or spirits is
technically called ethyl alcohol or ethanol
• Ethanol is able to cross the blood-brain barrier
Alcohol: definition
• Alcohols are lipid solvents – their ability to
dissolve lipids out of cell membranes allows
alcohol to penetrate rapidly into cells,
destroying structures, and killing the cell in the
process
• Therefore, alcohols are toxic, but they can also
be used to kill microbial cells
Alcohol: definition
• Ethanol is less toxic than other alcohols
• If it is sufficiently diluted, and taken in small
enough quantities, it can produce the effect
that people seek with a low enough risk to be
tolerable
• Used in this way, alcohol is a drug
• Like all drugs, it offers benefits and hazards
Binge drinking: consumption of 5 or more alcoholic drinks on
one occasion
Alcohol consumption
• Described as “drinks per day”
– Drink: the amount of a beverage that provides .5 fluid
oz. of ethanol
– Typically, equivalent to:
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1.5 oz. of distilled spirits (80 proof)
4-5 oz. of wine
10 oz. of wine cooler
12 oz. of beer
Alcohol content (by volume) of
beer and wine
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Non-alcoholic beer
“Light” beers
Regular beers
Stouts, malt liquors,
specialty beers
• Wines
0.5%
3-4%
5%
7%
7-24%
Proof
• The alcohol content of distilled spirits is
related directly to its proof.
– 100 proof is 50% alcohol
– 80 proof is 40% alcohol
Alcohol in the body
• Does not require digestion
• Absorbed from both the stomach and jejunum
• From the mucosal cells, transported by portal
vein to the liver
• In liver, is metabolized or released into
bloodstream
• In bloodstream, is rapidly distributed through
body’s intra- and extra-cellular spaces
Factors affecting absorption
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Amount
Speed
Presence/Absence of food
Carbonation
Gender/Individual differences
Genetic factors/Individual differences
Individual Differences in Alcohol
Metabolism
Affected by:
• Levels of alcohol dehydrogenase
• Body size - smaller livers
• Body Composition – less water to dilute
alcohol
• Hormonal fluctuations – heightened response
to alcohol during menstruation, or when taking
birth control pills
Oxidation of Alcohol begins in the
Stomach
•
Oxidation of alcohol occurs primarily in liver,
small amount occurs in stomach through the
action of two enzymes:
(1) Alcohol dehydrogenase (ADH)
(2) Aldehyde dehydrogenase (ALDH)
For more chronic alcoholics there is a third
pathway:
(3) Microsomal ethanol oxidizing system
Alcohol in the body: Small
Intestine
• Alcohol is also rapidly absorbed in the SI
• It gets absorbed and metabolized before most
nutrients
• This priority status helps to ensure a speedy
disposal and reflects two facts:
1. Alcohol cannot be stored in the body
2. Alcohol is potentially toxic
Oxidation of Alcohol in Liver
• Liver cells are the only other cells in the body that
make enough ADH to metabolize alcohol at an
appreciable rate
• Alcohol dehydrogenase (ADH) catalyzes the
conversion of alcohol to acetaldehyde (which is
toxic)
• Then, aldehyde dehydrogenase (ALDH) quickly
converts acetaldehyde to acetate
• “Antabuse” deliberately blocks conversion of
Alcohol metabolism
Alcohol metabolism
• Majority of alcohol metabolism occurs in the
liver, which contains significant amounts of
ADH and ALDH.
• The maximum rate of alcohol breakdown is set
by the amount of ADH available and its
activity level
Alcohol Effects: Brain
• 1. Alters
reasoning and
judgment,
depresses
inhibitions
(A)
• 2. Speech and
vision (C and
D)
Alcohol Effects: Brain
• 3. Voluntary muscle
control, impairs
motor skills (B, C,
D, E)
• 4. Conscious brain is
completely subdued,
and the person
passes out
Alcohol effects: Brain
• Brain cells die with excessive exposure to
alcohol. Not all brain cells can regenerate
(unlike liver cells)
• Some heavy drinkers suffer permanent brain
damage
Alcohol effects: Brain
• Korsakoff psychosis
• Characterized by ongoing memory and learning
problems
• Wernicke-Korsakoff syndrome
• Form of alcoholic encephalopathy
• Linked to severe thiamine deficiency
• Potentially fatal, occurs with alcohol-related
liver failure
Alcohol Effects: Liver
• Toxic to liver cells
• Alters metabolism of
nutrients and drugs
• Impairs ability to store
nutrients
Alcohol Effects: The Liver
• The earliest evidence of liver damage is fat
accumulation
• Fatty liver can appear after only a few days of
heavy drinking, and recedes with abstinence
• The liver can increase in weight from ~ 3
pounds, to over 10 pounds
• What causes the liver to become fatty?
Alcohol Effects: The Liver
• With regular, high intakes of alcohol, the liver
becomes chronically inflamed (alcoholic
hepatitis)
• The hepatitis may be treatable, but it is often
fatal
• With continued inflammation, the liver
becomes fibrous, and scarred: Cirrhosis
• About 10-20% of heavy drinkers develop
cirrhosis
Alcohol Effects: Upper GI
• Carcinogenic to upper
GI cells
• Increases gastric acid
production
• Inflames lining of
stomach
• Increases the likelihood
of reflux, gastritis, and
esophagitis
Alcohol Effects: Pancreas
• Toxic to pancreatic cells
• Impairs digestion and
absorption
• Alters secretion of
pancreatic hormones
• Increased risk for
pancreatitis, which
reduces digestive enzyme
production
The Hangover
• Symptoms can include
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pounding headache
Fatigue
muscle aches
Nausea
stomach pain
heightened sensitivity to light and sound
Dizziness
possibly depression, anxiety, and irritability
Causes
• Dehydration: dry mouth and headache
• Irritation of stomach and intestines: nausea,
stomach pain, vomiting
• Hypoglycemia: fatigue, light-headedness
• Disruption of sleep patterns: fatigue
• Congeners
Congeners
• Impurities produced during fermentation or
metals such as zinc that are added to certain
sweet liqueurs in order to enhance flavor.
• They contribute to the distinctive smell of the
beverage and may increase intoxicating effects
and subsequent hangover
• Found in: whisky, red wine, brandy
“Curing” A Hangover
• The most effective treatment is TIME
Others:
• Sleep
• Drinking hydrating beverages
• Eating
• Antacids
• Aspirin (may improve aches, but could irritate
stomach)
• Taking vitamin B6 before drinking may reduce the
severity of the hangover
Alcoholism and Malnutrition
Alcohol-induced alterations in nutrient
metabolism
(1) Interferes with activation of vitamins:
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Vitamin D
Thaimine
Riboflavin
Folate
Vitamin B6
Increases degradation of B-complex vitamins
(2) Increases urinary excretion of nutrients:
» B-vitamins
» Zinc
» Magnesium
Alcohol-induced alterations in nutrient
metabolism
(3) Decreases gluconeogenesis (due to excess
NADH)
(4) Limits glycogen storage
(5) Suppresses fatty acid oxidation
(6) Increase in mobilization of stored fatty acids
from adipocytes
Does Alcohol Cause Weight Gain?