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 (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).

Agribusiness Problems 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. Ex: Russet Burbank potatoes

“Ancient” Grains 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. Faro, Spelt, Flax, Buckwheat

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 We LOVE Ladybugs! Integrated Pest Management (IPM) Reduce pesticide use by 90% Use natural predators to manage pests (ex: wasps, ladybugs, viruses and bacteria, etc)