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Nutrition
Life Science Grade 7
What is a Nutrient?
 A nutrient is a chemical substance
in food needed by the body for
growth, energy, and life processes.
 The six nutrients are
carbohydrates, proteins, fats,
vitamins, minerals, and water.
Carbohydrates
 Carbohydrates are nutrients that
supply your body with energy.
 There are three kinds:
sugar
cellulose
starch
Sugar – A Simple Carbohydrate
 Are “simpler” compounds
 They are digested and
used quickly by your body.
 Sugar examples are
glucose, sucrose, fructose,
and lactose.
 They give your body short,
quick bursts of energy.
Starch and Cellulose Complex carbohydrates
 Are more “complex”
molecules
cellulose
 They take longer to digest
and use.
 They give your body
energy over long periods
of time.
starch
Proteins
 Proteins are nutrients that help your
body grow, build, and repair body
tissues.
 You need 8 essential “amino acids” from
food (the building blocks of protein).
 When carbohydrates and fats have been
used up, proteins can also be used for
energy.
Proteins
 Some food sources of protein are:
milk products, fish, meat, poultry,
beans, grains, and nuts.
Fats
 Fats are energy-storage nutrients.
 Fat that is stored in the body is
used for insulation and
cushioning of internal organs.
 Fats are classified as unsaturated
and saturated.
Unsaturated Fats
 come from plant sources
 are usually liquid at room temperature
 are often called “oils”
 are considered
healthier for you
Saturated Fats
 come mainly from animal sources
such as meat, eggs, and milk
products
 are usually solid at room temperature
 can give you too much cholesterol
which can clog your arteries
Vitamins
 help your body use other
nutrients
 help promote growth and
regulate body functions
 no one food contains them
all, but some foods supply
more than others
Common
Vitamins
Minerals
 are inorganic nutrients
 regulate many chemical reactions
in your body
 about 14 are used by your body,
calcium and phosphorus being
used in the largest amounts
Minerals
Water
 most chemical reactions in the
body need to take place in water
 body is 60% water by weight
 water is found in and around cells
and in plasma and lymph
 you lose about 2 Liters of water
every day through excretion,
perspiration, and respiration
Food Groups
 Nutritionists recommend eating a
variety of foods.
 Foods that contain the same
nutrients belong to a “food group”.
 Recommendations for how much of
each food group should be in your
daily diet are changing along with
new research.
Old Food Pyramid
New Food Pyramid
Alternate Food
Pyramid
Antioxidants
 Some chemicals that enter the body can
react with oxygen and cause cancer.
 Antioxidants prevent this from
happening.
 They are “substances that prevent other
chemicals from reacting with oxygen”.
 There are antioxidants in fruits and
vegetables, especially yellow-orange
pigmented ones.