This document discusses the six major classes of nutrients needed for human nutrition: proteins, carbohydrates, fats, vitamins, minerals, and water. It describes the functions and sources of each nutrient class. Proteins, carbohydrates, and fats provide calories and energy, while vitamins and minerals regulate body functions. Water is essential for survival and for nutrient transport within the body. A balanced variety of foods from the major food groups is needed to meet daily nutrient requirements.

1. Nutrition
Chapter 14, section 2

2. Why do you eat?
 A calorie is a measurement of the
amount of energy available in food.
 The amount of food energy a person
requires varies with activity level, body
weight, age, sex, and natural body
efficiency.

3. Classes of Nutrients
 Six kinds of nutrients:
◦ Proteins
◦ Carbohydrates
◦ Fats
◦ Vitamins
◦ Minerals
◦ Water

4. Proteins
 Used for
◦ Replacement and repair of body cells
◦ Growth
 They are large molecules that contain
carbon, hydrogen, oxygen, nitrogen
and sometimes sulfur.
 A molecule of protein is made up of
amino acids

5. Proteins continued…
 Sources of protein include:
◦ Meat
◦ Eggs
◦ Fish
◦ Beans
◦ nuts

6. Proteins continued….
 Your body needs 20 amino acids in
different combinations to make the
thousands of proteins used in your
cells.
 Most of the amino acids are made in
your cells…all except for 8.
 The 8 are called essential amino acids
and you must get them from the food
you eat.

7. Carbohydrates
 Usually the main sources of energy for
your body.
 Three types are: sugar, starch, fiber
◦ Sugars are called simple carbohydrates
◦ Starch and fiber are called complex
carbohydrates
◦ What are good sources of starch and
fiber?

8. Fats
 Also called lipids
 Necessary because they provide
energy and help your body absorb
vitamins
 Cushions your internal organs
 Found in cell membranes
 Why is excess energy from the foods
we eat converted to fat and stored for
later use?

9. Fats continued….
 Can be unsaturated or saturated
 Unsaturated are usually liquid at room
temperature (vegetable oils, fats in
seeds)
 Saturated fats are found in meats,
animal products and some plants.
 Saturated fats are usually solid at
room temperature and cause high
cholesterol

10. Fats continued….
 Cholesterol is made in your liver and
is a part of the cell membrane in all of
your cells
 High cholesterol may cause deposits
forming on the inside walls of blood
vessels which block the blood supply
to organs and increase blood
pressure…leads to heart attack and
stroke.

11. Vitamins
 Organic nutrients needed in small
quantities for growth, regulating body
functions, and preventing some
diseases.
◦ Vitamin D needed to use calcium
◦ Vitamin K needed by blood vessels to clot

12. Vitamins continued…
 Two groups
◦ Water-soluble: dissolve easily in water
 Not stored by your body so you have to consume
them daily.
◦ Fat-soluble: dissolve only in fat
 Stored by your body
 Some vitamins are made by your body
like Vitamin D when you are exposed to
sunlight.
 Vitamins K and B are made in your large
intestine with the help of bacteria that
live there

13. Minerals
 Inorganic nutrients
◦ Nutrients that lack carbon and regulate
many chemical reactions in your body
 There are about 14 that your body
uses, however calcium and
phosphorus are used in the largest
amounts for a variety of body
functions.
◦ One function is formation and
maintenance of bone

14. Minerals continued…
 Trace minerals are required only in
small amounts
◦ Example: copper and iodine
 Minerals are not used by the body as
source of energy
 Table 1 p. 408

15. Water
 Most important factor for survival next
to oxygen
 We could live for only a few days
without water…why? (p.408)
 Most of the nutrients we have talked
about can’t be used by your body
unless they are carried in a solution
(dissolved in water)

16. Water continued….
 Human body is 60% water by mass
 2/3 of your body water is located in
your body cells
 Also found around cells and in fluids
such as blood
 To replace water lost each day, you
need to drink about 2 Liters of liquids
 Some foods have water too

17. Water continued…
 When your body needs to replace lost
water, messages are sent to your
brain that result in a feeling of thirst.
 Drinking water satisfies thirst and
restores the body’s homeostasis.
When homeostasis is restored, the
signal to the brain stops and you don’t
feel thirsty anymore.

18. Food Groups
 Why do you need to eat a variety of
foods? (p.409)
 Food pyramid helps people select
foods that supply all the nutrients
needed for energy and growth.

19. Food Labels
 Make it easier to make healthful food
choices
 Can help you plan meals to meat
requirements
 Read handout from activity