How Nutrients
Become You
Chapter 3
You Are What You Eat
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Food is your body’s fuel
You need food to function just as a car needs
gasoline to function
When you eat, your body breaks the food down
into nutrients
What are Nutrients?
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Nutrients consist of various chemical substances
in food that make up the diet
They are essential to life and nourish the body
They provide energy and help build and
maintain body cells
6 Nutrient Groups
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Carbohydrates - Energy
Fats – Make up cell membranes
Proteins – helps make up body cells and helps
promote growth
Vitamins
Minerals
Water
Functions of Nutrients
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Build and Repair body tissues
Nutrient needs are greater during periods of rapid
growth (childhood, adolescence)
 Lack of adequate nutrition during growth may affect
physical size, strength and health
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Functions of Nutrients
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Regulate Body Processes
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Circulation of body fluids, digestions, absorption,
and metabolism rely on proper amounts of nutrients
Provide Energy
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Quality of the food you eat will determine how
well your body functions
Energy is needed for all life processes
(breathing, pumping blood, moving muscles)
You need energy every minute of the day
Carbohydrates, fats are your body’s main source
of energy. Protein provides energy in cases of
some sicknesses or starvation
How is Energy Measured?
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The energy value of food is measured in
kilocalories, also know as calories
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Carbohydrates provide the body with 4
kilocalories per gram
Fats provide 9 kilocalories per gram
Proteins provide 4 kilocalories per gram
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Video: The Digestive System
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Why is digestions described as both a
mechanical and a chemical process?
What Happens to the Food I Eat?
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Digestion occurs. This is the breakdown of food
into usable forms we can absorb
It starts in the mouth
In the Mouth
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Digestion starts when you see or smell food; saliva can
start flowing in the mouth
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The enzyme salivary amylase in saliva helps
break down starches
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Your teeth physically break down food by grinding it
into tiny pieces; known as chewing or mastication
Alpha amylase works at an optimal pH of 7 and a body
temperature of 98.6.
Demo with chalk and cracker
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The tongue contains taste buds that help us tell the
difference between salty, sour, sweet, and bitter
foods.
In the Esophagus
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The esophagus is a transportation tube from the
mouth to the stomach. When we swallow we are
closing a trap door in our throat called the epiglottis.
This allows food to go down the esophagus and
prevents food from going down the trachea or
windpipe into the lungs.
Muscles of the esophagus contract and relax
forcing the food into the stomach
THE LEAST AMOUNT OF DIGESTION
OCCURS IN THE ESOPHAGUS
Demo rubber tube
In the Stomach
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Stomach is widest part of the digestive system, and is
located on the left side of the body-can hold about 2 ½
pints of food
Stomach produces gastric juices that chemically
break down food
The food is moved around in the stomach for 3-4
hours to allow the chemicals to break down the food
into a cream-like liquid called chyme.
Now a value at the end of the stomach opens and sends
the food to the liver.
Demo Leaf
Digesting Nutrients
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Liquids leave the stomach before solids
Carbohydrates and proteins digest faster than
fats
This is why fatty foods give you a feeling of
fullness
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At this point, the food is mixed with more
chemicals. The liver produces a chemical called
bile, which is stored in the gall bladder. When
the gall bladder mixes bile with the chyme (our
food) it breaks down fat into tiny droplets.
Demo oil
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The pancreas also adds a digestive chemical as
the chyme leaves the stomach. This digestive
juice works on breaking down carbohydrates and
proteins.
Small Intestine
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The small intestines are approximately 18 feet long.
As the food passes through it is mixed with new
chemicals.
At this time it is digested long enough to be used by the
body.
About 95% of digestion occurs in the small intestine
Along the walls of the intestine are thousands of tiny
fingers called villi. Blood vessels (capillaries) in the
villi can absorb the tiny food molecules and send
them through the blood to the rest of the body.
Demo- tube with villi, and length of digestive tract.
Absorption of Nutrients
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Passage of nutrients from digestive to
circulatory and lymphatic systems
Water soluble nutrients
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Amino acids, monosaccharides, minerals, vitamin C,
B vitamins
Fat soluble nutrients
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Vitamins A, D, E, K, fatty acids, glycerol,
monoglycerides
Absorption of Nutrients
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Digested food molecules are passed through the
wall and into the blood stream and carried to
cells throughout the body – This is known as
absorption
Nutrients are absorbed in the small intestine and
the large intestine
Once nutrients reach your cells, they undergo
changes to produce energy needed to sustain life
(metabolism)
Large Intestine
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Whatever the body cannot use is sent to the large
intestine where water is removed. Water is necessary up
until this point for digestion.
Main function is to reabsorb water and send it into the
bloodstream.
Food will spend about 12 hours in the large intestine.
Undigested food is called solid waste feces.
This is stored in the rectum until it leaves the body.
Vocab to Know for Test 1
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Risk factor
Physical health
Nutrient
Ethnic food
Status food
Digestion
Peristalsis
mastication
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Wellness
Mental health
Social health
Culture
Food taboo
Kilocalorie
Metabolism
True or False
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Eating dog is a food taboo in the United States.
Stress is an uncontrollable risk factor for heart
disease.
The most digestion takes place in the esophagus.
Fats leave the stomach before liquids.
The nutrients carbohydrates, fats and proteins
provide your body with energy.
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Wellness is made up of what 3 types of health?
What are the top 3 leading causes of death?
What are the 6 nutrients?
What are some health risks of obesity?
What is the main internal factor that drives us to eat?
When do you form your beliefs about food?
Know the order of the digestion process
What are external factors that drive us to eat?
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Where does the most digestion take place?
Where does the least digestion take place?
In what order does food leave the stomach?
Which 3 nutrients provide energy?
Short Answer Questions (Choose 2)
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Name the six basic types of nutrients you must
obtain from the foods you eat.
How can emotions affect your food choices?
Explain.
What are the three main functions of nutrients?
What are two factors that affect individual food
preference?
What is the main job of the large intestine?