Transcript Chapter 14 Nutrition

Feeding the World
CHAPTER 14
Human Nutrition

Humans need energy to grow,
move, and repair our bodies.

All humans belong to one
species – so our dietary
requirements are the same.

Nutrients are divided into two
groups:

Macronutrients

Micronutrients
Nutrients

Macronutrients provide the energy
(fuel) our bodies need to function
(proteins, carbohydrates and fats)

Micronutrients are small amounts
of chemicals needed for our body’s
biochemical reactions

kcal kilocalories is how
macronutrients are measured

1 kcal = the amount of energy
needed to raise 1 kilogram of
water 1 degree Celsius
Carbohydrates

Made of carbon (C), hydrogen (H)
and oxygen (O)

Ratio of 1C:2H:1O

Ex: glucose (sugar) = C6H12O6

Basic Building block is sugar or
simple carbohydrate

Many sugars put together are
called starches or complex
carbohydrates

All carbs provide 4 kcal/gram
energy
Proteins

Made of amino acids

Amino acids have Nitrogen

Proteins are very large molecules

Hair, skin, blood, muscle, nails

All the proteins in your body are
made of just 20 amino acids in
different combinations

We can make 12 amino acids – the
other 8 we get from our food

Protein gives 4 kcal per gram of
energy
Lipids

Lipids are 3 fatty acids with an
alcohol molecule

Lipids make up all cell membranes
and lining for all our nerves

Two kinds of lipids:

Solid or hydrogenated at room
temperature – butter lard (animalbased fats)

Liquid or dehydrogenated at room
temperature – olive oil, canola oil,
corn oil (plant-based fats)

Lipids provide 9 kcal of energy per
gram
Vitamins and Minerals

Vitamins and Minerals
are Micronutrients

Important in
biochemical reactions
that release energy in
our bodies

Most micronutrients are
found in minimally
processed fruits and
vegetables
Nutritional Deficiency

Average adult requires 2500
kcalories per day

Adults that receive 90% or less
of this requirement are
undernourished

Adults that receive less than 80%
of the 2500 kcal per day are
seriously undernourished

Children that receive less than
90% can suffer permanent
damage to bones, teeth, brain
function
World Food Supply

Research and development in
agriculture have increased the
amount of food produced

Economics is the driving force
behind agricultural production

More crops = more money

Green Revolution (1960’s) new
strains of wheat and rice

Wheat and rice are the diet basis
for most of the world
Green REVOLUTION

New strains of wheat and rice
were disease resistant and could
adapt to many climates

Designed to help feed underfed
nations

Used modern machinery to
plant and harvest r- giving 4X
the crops from the same
farmland

PROBLEMS: poorest nations
didn’t have money for machines,
fuel or fertilizers – so only
developed countries used the
technology
Cash Crops

More wheat and rice mean
lower prices

Poor farmers were paid even
lower prices for their small
harvests

ANSWER: grow more
expensive crops that can be
exported to richer countries who
will pay for them

CASH CROP – crops grown
only for sale – not to feed the
farmer or the community
Aquaculture

Food doesn’t just come from the
land – the hydrosphere produces
200 billion tons of biomass each
year

Commercial fishing has
endangered over 40 of 280 fish
species

ANSWER: aquaculture – raising
fish and shellfish in salt or
freshwater pools or ponds

PROBLEMS: water becomes
contaminated with run-off and
chemicals used to feed fish
Hydroponics

Water isn’t just used for fish –
plants can also be grown in water

Hydroponics – plants grown
without soil

In the produce section of the
supermarket: tomatoes, lettuce,
peppers, radishes, cucumbers,
herbs and flowers grown without
soil in controlled conditions using
nutrient solutions and recycled
water

Usually pesticide free because
grown in controlled conditions
indoors
Modern Farming
Techniques

Huge farm machinery has
replaced man and animal labor

Middle of 20th century-began to
use machines powered by fossil
fuels
 Called “Industrialized
Agriculture”
 Efficient and productive
 Require large amount of
energy, pesticides, fertilizers.
 Often run by corporations
(agribuisinesses).


Use of pesticides

Increase in resistant insects and other pests.

1992-California white fly infestation

DDT and decline in bald eagle population
Monoculture

Farms growing only the 1 or 2 crops that bring in the
most money.

Crops genetically identical = more vulnerable to disease

Soil depleted of minerals = soil loses ability to produce
healthy crop.
Quinoa

New grains
 Not adapted to local
conditions
 Looking to use local grains in
many areas
 Ex: quinoa – grows better
than wheat or rice in
mountainous areas, high in
protein, can be made into
flour, cereal, beverages and
livestock feed.
Sustainable Agriculture

Modern agriculture has resulted in:
soil erosion, deforestation,
desertification, hunger, war, and
environmental damage.

Sustainable agriculture-called
regenerative farming; based on crop
rotation, reduced soil erosion, pest
management, and minimal use of soil
additives.
Crop Rotation

Crop Rotation- changing the type of crop grown in
an area on a regular cycle.

Usually 1 to 6 years per cycle

Prevent soil from becoming depleted of nutrients
(nitrogen).

Avoid use of synthetic fertilizers.

Cover Crop- nonfood plants grown between grown
seasons on land usually left empty.

Restore nitrogen to the soil and help to reduce erosion
Reducing erosion

Erosion- process where soil is lost, transported, and
reformed. Caused by wind and flowing water.

When topsoil removed, loss of nutrients= useless for
farming.

Can be reduced by irrigation and soil management.

Irrigation-watering of fields; use systems that deliver
less water, but directly to the roots reduces erosion.

Tilling-turning the soil so lower layers are brought to the
surface.

Destroys weeds and other pests, brings nutrients to
the surface, improves drainage, and aerates the soil.

Wastes water, uses energy, can increase erosion.
Irrigation
Tilling
Pest Management

Integrated Pest Management
(IPM)

Reduce pesticide use by 90%

Use natural predators to manage
pests (ex: wasps, ladybugs,
viruses and bacteria, etc)