Transcript BIOL 103 Lecture Ch 7-2 Proteins for Students

Proteins and Amino Acids:
Function Follows Form
BIOL 103, Chapter 7-2
Today’s Topics
• Proteins in the Diet
• The Pros and Cons of Vegetarian Eating
• The Health Effects of Eating Too Little or Too
Much Protein
Proteins in the Diet
• Recommended protein intake
– Adult RDA = _________________________
– __________ have highest needs relative to body
weight
• Why? ___________________________________
• Physical stress ___________ your body’s needs
for proteins
– Infection, burns, fevers, surgery, intensive weight
training
• Consumption in the US
– Generally within or higher than recommended range
Problem Set 7, Question 1:
• How is it that our bodies are able to synthesize
so many proteins in our body when our
dietary protein requirement is relatively low?
Protein Quality
• Protein Quality
– Complete proteins: supply _____ essential amino
acids
• ________________________
• Examples: animal proteins, soy proteins
– Incomplete proteins: _______________ essential
amino acids
• ________________________
• Examples: most plant proteins
Protein Quality
• Incomplete and Complementary Proteins
– Except soy, proteins in other plant foods is
incomplete (lacks 1 or more essential AA).
– _________ incomplete complementary proteins =
___________________
• Examples: rice and beans, peanut butter and bread,
pea soup with crackers, corn and tortilla.
Evaluating Protein Quality
• A high-quality protein:
1. Provides ______________________ at amounts the
body needs
2. Provides __________________________
________________________for making nonessential amino acids
3. Easy to ____________
4. Protein digestibility-corrected amino acid score
(PDCASS): measure of protein quality that takes
account the AA composition of the food and the
digestibility of the protein.
Proteins and Amino Acids as Additives
and Supplements
• Protein and AA additives
– Contribute to
• Protein and AA
supplements
– Used for a variety of
reasons: dieters, athletes,
certain diseases.
– Risks are unknown
Vegetarian vs. Vegan
Vegetarian
• ___________________
• Don’t Eat:
• Types:
– Ovo-vegetarian:
– Lacto-vegetarian:
• Products: Don’t mind using
animal-derived products.
Vegan
• ______________________
• Don’t Eat:
• Products: Avoids using
______________________
________ including
clothing, cosmetics,
household, foods.
Pros and Cons of Vegetarian Eating
Problem Set 7, Question 4
•
•
•
•
•
Health Benefits
Less ___________________
More magnesium, folate
More _________________
More _________________
______________________
Reduces risk for heart
disease, hypertension, and
cancer.
Health Risks
• Vegans may be low in:
calcium, iron, zinc, vitamin
D, vitamin B12
• Higher intake of _________
• More restrictive food
choices = _______________
The Pros and Cons of Vegetarian Eating
• Diet recommendations (pg. 258):
1.
2.
3.
4.
Choose a variety of foods
Choose whole, unrefined foods
Choose a variety of fruits and vegetables
Choose lower-fat dairy products and eggs in
moderation
5. Consume a regular source of vitamins B12 and D
• Fortified foods or supplements
The Health Effects of Too Little Protein
• Dietary protein = essential amino acids
• Protein deficiency: ______________________
________________________
• ________________________________
– Kwashiorkor: _______________________
• Symptoms: _____________, poor growth, bloated belly
• Affects those between age of 18-24 months old
• Associated with extreme poverty
The Health Effects of Too Little Protein
• PEM, cont.
– Marasmus: _____________________________
• Chronic PEM; “withering”
• Affects Infants and 6-18 months old children
• Usually the children are _____________ for their age
• How to treat?
– Nutritional rehabilitation
• Gradual and careful refeeding
• Must start with fluid and electrolyte balance, then
introduce nutrients
The Health Effects of Too Much
Proteins
The Health Effects of Too Much
Proteins
1. Strains kidney function
– Too much protein overwhelms kidneys, which
need to excrete products of protein breakdown
2. Obesity
– Too much protein, becomes fat.
– May alter ________________ 
______________ ______________________
The Health Effects of Too Much
Proteins
4. Heart disease
– If you eat too much ________________ 
increased saturated fat and cholesterol intake
5. Cancer
– Increased risk for certain types of cancer if you
eat red meat
•
Example: animal protein/pork/beef and colon cancer
Problem Set 7, Q5
• Name two health effects related to consuming
a very high protein diet.