Feeding the World

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:

1. Macronutrients (proteins, carbs, lipids)

2. Micronutrients (vitamins)

Nutrients Macronutrients provide the

energy (fuel) our bodies need to function (proteins, carbohydrates and fats)

Micronutrients (vitamins and minerals) 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 (essential amino acids)

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)- saturated fats

Liquid or dehydrogenated at room temperature – olive oil, canola oil, corn oil (plant-based fats)- unsaturated 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 or malnurished

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 - 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. DDT and decline in bald eagle population THINK: Biological Magnification… what is it?

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.

Solutio

n?

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)