Lecture Discovering nutrition - Chapter 4a: Spotlight on alcohol

Spotlight on
Alcohol


The Character of Alcohol
• Ethanol

– The alcohol in beer, wine, spirits
• Methanol

– Wood alcohol—poisonous



Alcohol: Is it a Nutrient?
• Provides energy
– 7 kcal/g
• No other nutritive value


Alcohol and Its Sources
• Fermentation
– Yeast cells metabolize sugar to make
alcohol
• Alcoholic beverages
– Beer: 5–6% alcohol
– Wine: 8–14% alcohol
– Liquor: 35–45% alcohol
• “Proof” is twice the alcohol percentage

Alcohol Absorption
• No digestion required
• Absorbed from mouth,
esophagus, stomach,
and small intestine
• Absorption slowed by
food
• 80–95% of alcohol is
absorbed unchanged


Alcohol in the Body
• Metabolizing small amounts of alcohol
– Alcohol dehydrogenase
• Alcohol  acetaldehyde
– Aldehyde dehydrogenase
• Acetaldehyde  acetate
– Acetaldehyde, acetate converted to acetyl
CoA
• Acetyl CoA molecules built into fatty acids


Alcohol in the Body
• Metabolizing large amounts of alcohol

– Overwhelms alcohol dehydrogenase
system
– Uses microsomal ethanol-oxidizing system

(MEOS)


Alcohol in the Body
• Removing alcohol
from circulation

– Liver
metabolism
limited
– Blood alcohol
level falls slowly


Alcohol in the Body
• Individual
differences in rate
of alcohol
metabolism

– Gender
– Race/ethnicity
– Age


When Alcohol Becomes a
Problem
• Alcohol in the brain and nervous system
– Depressant; affects all parts of brain
• Alcohol’s effect on GI system

– Esophagitis and gastritis



When Alcohol Becomes a
Problem
• Alcohol and the liver
– Fatty liver
– Fibrosis
– Cirrhosis
• Fetal alcohol syndrome
– Physical abnormalities
– Mental retardation
– Low birth weight and poor growth


Fetal Alcohol Syndrome
• Can have a devastating impact when
consumed during pregnancy
• Variety of congenital defects:
- Mental retardation
- Coordination programs
- Heart, eye, and genitourinary
malformations
- Slowed growth rates



Alcoholics and Malnutrition
• Poor diet

– Alcohol provides
energy but no
nutrients
– Economic factors
– Lack of interest in
food; GI problems


Alcoholics and Malnutrition
• Vitamin deficiencies
– Alcohol interferes with vitamin
metabolism
– Folate, thiamin, and
vitamin A
• Mineral deficiencies
– Inadequate diet; fluid losses
– Calcium, magnesium, iron, and zinc
– Some mineral levels are elevated


Alcoholics and Malnutrition
• Macronutrients
– Alcohol interferes with amino acid
absorption
– Alcohol raises blood levels of fats
• Body weight
– Inconsistent effect of alcohol calories on
weight

Does Alcohol Have Benefits?
• Moderate drinking has been associated
with reduced mortality
• Heart disease
– French paradox: red wine



Does Alcohol Have Benefits?
• People who should not consume alcohol:
– Those who cannot moderate their intake
– Children and adolescents
– Those taking certain medications
– Those with illnesses worsened by alcohol
– Those who drive or operate machinery
– Pregnant or breastfeeding women
– Those with a strong family history of
alcoholism