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Protein
The Body’s Building Blocks
What is Protein?
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Protein is an energy supplying nutrient made
up of carbon, hydrogen, oxygen and nitrogen.
The nitrogen is what makes it different from
carbohydrates and fats.
Proteins are formed from the combining of 20
different amino acids into different
combinations and patterns.
There are at least 30,000 different types of
proteins with a specific job or function, DNA is
one of them.
Functions of Protein
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Build and maintain tissues – protein is
needed to form the structure of muscles,
organs, skin, blood, hair, nails, and every
other body part.
Make important compounds – these
compounds include enzymes, which cause
specific chemical reactions in the body.
(example – digestive enzymes)
Function of Protein (cont.)
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Regulate mineral and fluid balance – help
carry sodium and potassium from one side of
cell walls to the other.
Maintain acid-base balance – maintains the
correct level of acidity of body fluid.
Carry vital substance – helps transport fats,
iron and other nutrients, and oxygen through
the body.
Function of Protein (cont.)
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Provide Energy – If carbohydrates and fats
are lacking in the diet, the body will use
proteins as an energy source.
Food Sources of Protein
Animal Sources: Animal flesh is the largest
source of protein in a meat-eating culture.
Although meat is an excellent source of
protein, some meat products are high in fat.
* Source of Complete Proteins
 Plant Sources: Protein is found in grains,
nuts, seeds, and legumes (peanuts, kidney
beans, lentils, chickpease, etc.)
* Source of Incomplete Proteins
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Types of Vegetarianism
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Vegans – no food from any animal sources
Lacto-vegetarians – eat dairy products, but
no meat products or eggs
Lacto-ovo vegetarians – dairy products and
eggs, but no meat products
Semivegetarians – eat dairy, eggs, poultry,
and seafood, but no red meat
Reasons for Vegetarianism
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Religious reason
Health reasons
Socioeconomic reasons
Environmental reasons
Humanitarian reasons
* Vegetarians must be sure to choose
Complementary proteins.
The RDA for Protein
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14 – 18 year-old males : 52 grams
14-18 year-old females: 46 grams
10-35% of your calories should come from
protein. Example: a young woman who
needs 2,400 calories a day should eat a
minimum of 240 calories from protein.
Follow the food guide to ensure you get
enough the RDA of protein.
Risks of too little protein
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Negative nitrogen balance
Protein-energy malnutrition
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Kwashiorkor – child does not reach full growth
potential, common in poor cultures
Marasmus – muscles and tissues begin to waste
away, child becomes thin, weak, and susceptible to
infection and disease
Excess proteins in diet
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Liver and kidney problems
Calcium Loss
Excess body fat