Download Lecture 14

Why Talk about Alcohol?
Lecture 14:
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
Alcohol Metabolism
• Liver works to clear alcohol from blood
before blood goes to rest of body
• Breaking down alcohol uses up lots of
niacin and pantothenic acid (B vitamins)
• Liver makes alcohol dehydrogenase
which can digest alcohol
• These vitamins can’t be used for other
reactions such as glycolysis, TCA cycle,
and electron transport chain
• 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 in Liver
Fat (triglycerides)
NAD+ NADH + H+
Alcohol
(ethanol)
Alcohol
dehydrogenase
Acetaldehyde
Fatty acids
NAD+ NADH + H+
Acetaldehyde
dehydrogenase
Acetate
Acetyl CoA
CoA
TCA
Cycle
NAD=niacin
CoA=pantothenic acid
• Excess Acetyl CoA gets made into fat
Fatty Liver
1) Fatty acids are not processed by
liver when it is metabolizing alcohol
2) Alcohol gets turned into fatty acids
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 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 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 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 and Folate
Alcohol Induced Deficiencies
• Minerals
– Calcium, Magnesium, Zinc, Iron
• Vitamins
– B Vitamins: folate, thiamine and B6
– Fat-soluble vitamins: A, C, D, E, K
Other effects of Alcohol
• Acts as a diuretic
– Causes loss of water and electrolytes
• 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
Alcohol’s Effects on the Brain
1) Frontal lobe:
Alcohol interferes
with judgment and
reasoning
Numbered in
order of
occurrence
• Beer increases gastric acid secretion
– Higher risk of ulcers
• Effects on brain put one at higher
risk for injuring self and others
3) Pons, Medulla oblongata:
Alcohol affects voluntary muscle
control and coordination.
2) Midbrain: Alcohol
impairs speech and
vision
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