Feeding the World CHAPTER 14
Feb 23, 2016
Feeding the WorldCHAPTER 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 (animal-based 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.
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.
Quinoa
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)