Download 16-1 The Importance of Food

16-1: The Importance of Food
Or “We Are What We Eat”
Four Classes of Organic Compounds
The 4 ORGANIC COMPOUNDS that
make up most of living organisms
are:
Carbohydrates
Proteins
Lipids
Nucleic
Acids
How do organisms get the organic
compounds that they need?

They can make some of them.
Plants make all the organic compounds
they need.
 They must take in inorganic
compounds that they use to make
organic compounds.


They must eat some of them.
Animals must consume most of the
organic compounds they use.
 Many are digested (broken down) into
their components and then assembled
into new compounds.

Our Focus
We will focus our studies on:
 What humans obtain from the food they eat
 What different nutrients are needed for in
our bodies
Later we will investigate the food pyramid, the
digestion and absorption of food and
maintaining a healthy weight.
The Six Basic Nutrients in Food
1.
2.
3.
4.
5.
6.
Proteins
Carbohydrates
Fats and Oils
Vitamins
Minerals
Water
Proteins
Used for growth and repair of
body tissues
 Used as enzymes to regulate
chemical processes in your cells
 Used as antibodies to fight off
infection
 Used for the production of
hormones that regulate the
physiology of your body

Proteins

Found in many foods. Protein-rich foods
include:
 Eggs
 Meats
From Animals
 Fish
 Milk and cheese
 Dry Beans, including soybeans
From
 Peas
Plants
 Some Nuts
Proteins
Proteins from animal sources are the
most complete – complete proteins
contain all the amino acids your body
needs to build the proteins it needs.
 The egg is considered the most
complete protein for us to eat.

Proteins
Foods from plant sources contain less
complete proteins
 Most people can still get all the
protein they need from plant sources
if they choose from the legume group
(beans, peas, peanuts, etc.)

Carbohydrates
 Usually
the major source of
energy in our diet
 Also provides fiber or bulk
 Includes:
Sugar
Starch
Fiber
Carbohydrates

Found in Grains and Grain Products
Cereals
 Breads
 Pasta
 Rice, Barley, Etc.


Also in Fruits and Vegetables
How do we measure energy in
food?
The amount of energy that food
provides is measured in Calories.
A food Calorie is defined as the amount
of energy needed to raise 1 kg of
water by 1°C. (equal to 1,000 calories
in physical science)
How do we measure energy in
food?
Sugar and starch provide 4 Calories
of energy per gram.
 Fiber, which is not digested, does not
provide any calories.
 Although protein is not primarily
eaten to provide energy, if the body
does use it for energy it also provides
4 Calories per gram.

Fats and Oils (Lipids)
Provide the body with energy
 Fats are a necessary component of all
cells
 Fat in our bodies cushions and
supports vital organs
 Fat provides our bodies with insulation

Fats and Oils (Lipids)
Lipids supply over twice as much
energy per gram than either protein
or carbohydrates do (9 Calories per
gram)
 Mono- and Poly- unsaturated fats are
believed to be more healthy for us to
consume

Fats and Oils (Lipids)
Sources of lipids in our diets include:
 Meats
 Cheeses
 Nuts
 Vegetable Oils, Margarines and Butter
 Many prepared foods including baked
goods and fried foods
Vitamins
A vitamin is any of the organic
compounds required by the body in
small amounts for metabolism, to
protect health and for proper growth
in children.
 There are 13 well-identified vitamins;
they are not chemically related.
 They generally act as catalysts in
combination with proteins/enzymes.

Vitamins

Classified into two types
Fat Soluble that can be stored in the
body’s fat – A, D, E and K
 Water Soluble that cannot be stored and
need to be eaten frequently (daily if
possible)– the 8 B vitamins and Vit. C


The only one that can be made by our
bodies is Vitamin D
Vitamins
Each vitamin performs one or more specific
functions in our bodies. Some things they
are important for include:





Red blood cell formation
Vision
Blood Clotting
Amino Acid, energy, and carbohydrate
metabolism
Formation of bones, teeth and connective tissue
Vitamins

Vitamins come from a variety of food
sources, for example:
Vit. A (β carotene) – Yellow and green
vegetable, egg yolks, etc.
 Vit. C – citrus fruits, tomatoes, etc.


Many foods are good sources of one
or more vitamins, especially
vegetables, whole grains and meats
Vitamin Deficiencies
Diseases can result from a lack of
specific vitamins:
Scurvy – lack of Vit. C, used to be a
problem for sailors who did not get fresh
fruits for long periods of time
 Rickets – lack of Vit. D causing
deformed bones and bowlegs (Not
usually a problem in the tropics; why
not?)

Vitamin Deficiencies
Diseases can result from a lack of
specific vitamins:
Blindness – Lack of Vitamin A is still a
major cause of blindness of children in
poor countries
 Pellagra – Niacin (B3) deficiency
 Beriberi – Thiamine (B1) deficiency

B Vitamins

There are 8 known
B vitamins
 B1- Thiamine
 B2- Riboflavin
 B3 - Niacin
(Nicotinic Acid)
 B6 – Pyridoxine
B12 – Cobalamin
 Folic Acid
 Pantothenic Acid
 Biotin

Minerals
Minute amounts of metallic elements
that are vital for the healthy growth
of teeth and bones
 Also function in enzyme action,
muscle contraction, nerve reaction,
oxygen transport, and blood clotting

Minerals

Iron – needed for oxygen transport
(part of the hemoglobin molecule)
 Not

Calcium – vital for normal cell
function and a major component of
bones and teeth
 Not

enough causes anemia
enough can lead to osteoporosis
Phosphorus – an important part of
DNA, RNA and ATP (an energy
transferring molecule); part of bones
Minerals
Potassium, magnesium and sodium–
needed for muscle and nerve function
 Iodine – needed by thyroid

 Not

enough results in goiter formation
Sodium and chloride – water balance
 Too
much can contribute to high blood
pressure

Fluorine – part of bones and teeth
 Helps
prevent cavities
Minerals

Other essential minerals include:
Zinc
 Selenium (poisonous if too much)
 Copper
 Manganese
 Chromium
 Molybdenum
 Sulfur

Minerals

Others that may be
essential include:
Boron
 Nickel
 Silicon
 Tin
 Vanadium

Water
Needed because:
 Our bodies are 65% water
 All the chemical reactions in our
bodies occur in water
 Water carries nutrients throughout
our bodies (blood is 90% water)
 Water helps maintain correct body
temperature
Water
Water comes both from what we drink
and from what we eat.
 Fruits and vegetables often contain
80-90% water and meat has about
50%.
 We need about 2.4-2.8 liters per
day(8-10 cups) to maintain hydration.
