Transcript Vitamins and Minerals

Unit 10:
Food and Digestion
Why You Need Food
• Food provides your body with
materials for growing and gives
you energy.
• Nutrients- the substances in food
that provide the raw materials
and energy that the body needs.
6 Groups of Essential
Nutrients
• Carbohydrates
• Vitamins
• Fats
• Minerals
• Proteins
• Water
Energy
• Calorie- The amount of energy needed
to raise the temperature of one
gram of water by one degree
Celsius.
• Used to measure the amount of energy
in foods.
• You need a certain amount of calories
each day, depending on your age and
level of physical activity.
Carbohydrates
• Made of carbon, hydrogen, and
oxygen.
• 1 gram of carb. = 4 Calories of energy
• Carbs. provide the raw materials to
make cell parts.
• 45-60% of your diet should come from
carbs.
Simple Carbohydrates
• Glucose- a simple carb. that is the
main source of fuel for cells.
• Most foods do not contain glucose,
your body makes it from other types
of sugar.
• Glucose is the form of sugar that your
body can most easily use.
Complex Carbohydrates
• Made of many sugar molecules that are
linked together.
• Starch- a complex carb. found in
potatoes, rice, wheat, and corn.
• Your body breaks down starch to get
energy.
• Fiber- complex carb. found in plants. Cannot
be broken down into sugar by the body.
- Food and Energy
Carbohydrates
• In addition to providing
energy, carbohydrates
provide the raw materials
to make cell parts.
Fats
• Made of carbon, hydrogen, and oxygen
• One gram of fat = 9 Calories of
energy
• Functions of fats:
- Make up cell membrane
- Protects internal organs
• No more than 30% of daily intake
should come from fat.
Types of Fats
Saturated
Solid at room temp,
meat and dairy
Unsaturated
Liquid at room
temp, cooking
oils
Trans
Made by adding
Hydrogen to veg.
oils, Help foods
stay fresh,
margarine, chips
Fats
- Food and Energy
• Many foods contain saturated, unsaturated, and trans
fats. Unsaturated fats are considered to be more
healthful than saturated fats and trans fats.
Proteins
• Made of carbon, hydrogen, and
oxygen, and nitrogen
• Needed for tissue growth/repair and
chemical reactions.
• 10-35% of your daily diet should come
from proteins.
• Amino Acids- link together to make
proteins.
- There are 20 amino acids.
- Your body can make some amino
acids.
-Essential amino acids- must come
from foods you eat.
• Complete proteins- contain all of the
20 amino acids, come from animals
- Ex: meat and eggs
• Incomplete proteins- only have
some amino acids, come from plants
-Ex: beans, grains, nuts
• To get all of the essential amino
acids, you must have a varied diet.
Vitamins and Minerals
• Your body only needs very small
amounts.
• Do not provide energy.
• Help body carry out processes.
• Vitamins- helper molecules for
chemical reactions.
- Ex: Vitamin K helps blood clot
• Fat-soluble vitamins- stored in fatty
tissues in the body.
• Water-soluble vitamins- dissolve in
water, not stored in the body.
• Scurvy- disease caused by lack of
vitamin C. Causes bleeding gums,
stiff joints, and wounds that won’t
heal.
- Food and Energy
Vitamins and Minerals
• Vitamins act as helper molecules in a variety
of chemical reactions in the body.
• Minerals- nutrients that are not made by
living things.
• Present in soil, absorbed through plant
roots.
• Calcium- needed for strong bones.
• Iron- needed for red blood cell function.
• Both vitamins and minerals are needed in
small amounts to help chemical reactions
occur.
Vitamins and
Minerals
- Food and Energy
• Nutrients that are
not made by living
things are called
minerals.
Water
• Makes up about 65% of your weight.
• The most important essential nutrient
because all of the body’s processes
take place in water.
• Normal recommended daily amount of
water = 2 liters/day
Guidelines for a Healthy Diet
• United States Department of
Agriculture (USDA)- provides
personalized guidelines to stay
healthy
• 13-year-old girl needs 1600-2200
Calories/day.
• 13-year-old boy needs 1800-2400
Calories/day
Food Labels
• Allow you to evaluate a single food or
compare two different foods.
• Serving Size- the size of a single
serving and how many are in the
container.
• Calories- how much energy you get from one
serving.
• Percent Daily Value- how the nutritional
content of one serving fits into the diet.
Based on a 2,000 Cal/day diet.
• Ingredientslisted in order by
weight, starting
with the main
ingredient.
• Dietary
Reference
Intakes (DRIs)amount of
nutrients needed
every day.
Food Labels
- Healthy Eating
• Food labels allow you to evaluate a
single food as well as to compare
the nutritional value of two
different foods.
1. Serving Size: This information tells you the size of a
single serving and the number of servings in the container.
2. Calories: This information tells you how much energy you
get from one serving of this food, including how many calories
come from fat.
3. Percent Daily Value: The Percent Daily Value shows you
how the nutritional content of one serving fits into the
recommended diet for a person who consumes 2,000 calories a
day.
4. Ingredients: The ingredients are listed in
order by weight, starting with the main
ingredient.
- Food and Energy
Percentages
• A percentage (%) is a ratio that compares a number to
100. For example, 30% means 30 out of 100.
• Suppose that a person eats a total of 2,000 calories in
one day. Of those calories, 300 come from protein.
Follow these steps to calculate the percentage of
calories that come from protein.
• 1. Write the comparison as a fraction:
• 2. Multiply the fraction by 100% to express it as a
percentage:
- Food and Energy
Percentages
• Practice Problem
• Suppose that 540 calories of the person’s 2,000
calorie total come from fats. What percentage of the
calories come from fats?
• 27%
Digestion
• 3 functions of the digestive system:
- Breaks down food into molecules
- Absorbs molecules into the blood
- Eliminates wastes from the body
• Digestion- the process by which the
body breaks down food.
- Mechanical- food is physically
broken down. Ex: Chewing food
- Chemical- chemicals break foods
down. Ex: Amylase breaking
down starch.
• Absorption- the
process by which
nutrients pass
through the wall
of your digestive
system into your
blood.
• Materials that are
not absorbed are
eliminated.
- The Digestive Process Begins
The Mouth
• Both mechanical and chemical
digestion begin in the mouth.
The Mouth
- The Digestive Process Begins
• The shape of an enzyme molecule is specific
to the shape of the food molecule it breaks
down. Here an enzyme breaks down a starch
into sugars.
The Esophagus
• Esophagus- muscular tube that connects the
mouth to the stomach.
• Epiglottis- flap of tissue that seals off the
wind-pipe when you swallow. Makes food
go down the esophagus instead of the
wind-pipe.
• Mucus- thick, slippery substance produced
by the body. Lines the esophagus.
• Peristalsis- wave-like motion caused by
contractions of smooth muscles in the
esophagus.
The Stomach
• Stomach- J-shaped muscular pouch located
in the abdomen.
• Mechanical and chemical digestion happen in
the stomach.
- Mechanical digestion- churning
- Chemical digestion- digestive juice
*Pepsin- enzyme in digestive juice
* Hydrochloric Acid- strong acid in
digestive juice
• Stomach is lined with mucus, prevents
stomach acid from burning the stomach
cells.
- The Digestive Process Begins
The Stomach
• Most mechanical digestion and some chemical
digestion occur in the stomach.
Final Digestion and Absorption
• Small Intestine- part of digestive system
where most chemical digestion takes
place.
• About 6 meters long.
• Named for its small diameter- 2 to 3 cm
wide.
• Almost all chemical digestion and absorption
takes place in the small intestine.
The Small Intestine
- Final Digestion and Absorption
• The small intestine is the part of the
digestive system where most chemical
digestion takes place.
The Small Intestine
- Final Digestion and Absorption
• Tiny finger-shaped projections
called villi line the inside of the
small intestine. Villi absorb
nutrient molecules. The molecules
pass from the villi into blood
vessels. Villi increase surface
area.
The Liver
• Liver- located in the upper right portion of
the abdomen.
• Largest organ inside the body.
• Role of the liver in the digestive system is
to produce bile.
• Bile- molecule that breaks up fat particles.
• Gallbladder- bile comes here from the liver,
bile is stored here.
• Bile physically breaks up food.
The Pancreas
• Pancreas- triangular shaped organ between
the stomach and small intestine.
• In the digestive system, produces enzymes
that flow into the small intestine and help
break up starches, proteins, and fats.
The Large Intestine
• Large Intestine- last section of the
digestive system.
• About 1.5 meters long
• Named for its wide diameter (about 6 cm).
• Contains helpful bacteria that aid in
digestion and produce vitamins (Vitamin
K).
• Absorbs water into the bloodstream.
The End
• After undigested food passes through the
large intestine, it is eliminated from the
body.
• Rectum- short tube at the end of the
digestive tract where waste material is
converted into a solid.
• Anus- muscular opening at the end of the
rectum where waste material is eliminated
from the body.