food and nutritioncfink/es 10/es 10 powerpoint lectures... · 2018-08-20 · 1 study questions 1....
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Study Questions
1. Describe proteins (complete vs. incomplete), carbohydrates (simple vs. complex) and fats (saturated, unsaturated and trans) in the nutritional context.
2. Explain how much of one’s diet should come from proteins, fats and carbohydrates.
3. Compare and contrast the terms undernourished vs. malnourished.
4. Why do food shortages exist?
5. What are humans’ major food sources, and what problems arise in producing/harvesting these?
6. Discuss factors required for successful agriculture.
7. What is meant by the terms “green revolution” and “sustainable agriculture?” 1
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Food, Nutrition and Agriculture
Food and Nutrition
Food gives us:
•Energy
•Physical structure
• Vitamins and Minerals
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Basic Food Requirements
Approximately 2,000 calories per day
•Proteins (10-35%)
•Carbohydrates (40-60%)
• Fats (20-35%)
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Recommended Dietary Allowance for Protein
Grams of proteinneeded each day
Children ages 1 – 3 13
Children ages 4 – 8 19
Children ages 9 – 13 34
Girls ages 14 – 18 46
Boys ages 14 – 18 52
Women ages 19 – 70+ 46
Men ages 19 – 70+ 56
http://www.cdc.gov/nutrition/everyone/basics/protein.html
ProteinsCompete (whole): contain all essential amino acids
Incomplete: contain only some of essential amino acids
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Carbohydrates (sugars, starch, fiber)
•Simple Carbohydrates: single or double sugars (mono, disaccharides)
•Complex Carbohydrates: 3 or more sugars (polysaccharides)
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Single sugars include:
•Glucose•Fructose •Galactose
Double sugars include:
•Lactose•Maltose •Sucrose
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Complex Carbohydrates: (starch, dietary fiber)
•Legumes, starchy vegetables, whole-grains
Fiber requirement:14 grams per 1000 calories consumed
Chains of glucose molecules make up starch molecules and fiber (cellulose) molecules
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Fats (and Cholesterol)
Saturated: animal products
Unsaturated: nuts, vegetable oils, fish (omega-3, omega-6)
Trans fat: partially hydrogenated oil
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Cholesterol: “fatty” molecule in animal products
HDL: high-density lipoprotein cholesterol, or “good”
LDL: low-density lipoprotein cholesterol, or "bad"
Recommendation: <300 mg cholesterol per day
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Recent Diets in the Media
•Adkins (low carb)•Paleo (no grains, legumes, dairy, etc.)•Mediterranean (low red meat, sugar, fat)•Ornish (low fat)•Gluten-free
•And many others!
• In 1960, nearly 60% of people in developing countries were chronically undernourished
• World population has increased 1.7%; food production has increased 2.2%
• Less than 20% of people in developing countries now chronically undernourished
Food security: the ability to obtain sufficient, healthy food on a day-to-day basis
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Undernourished: insufficient calories
Over 850 million people suffer chronic hunger
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Why are people undernourished?
Current world food supply could support world population with 2200 kcal per day!
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Factors Contributing to World Hunger Include:
•Bad weather (drought, famine)
•Political instability
•Social crises
•Poverty
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Malnourished: imbalanced or insufficient nutrients
Malnutrition can lead to:
• Mental deficiencies
• Physical deficiencies
• Blindness
• Diabetes
• Cancer
• Heart attack
• Obesity 16
Overweight people now outnumber underweight people
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To be healthy, one needs a balance of both amount and type of food
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Food Sources
• Major Crops (wheat, rice, maize)
• Fruits/Vegetables
• Meat
• Seafood
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Wheat Rice
Corn Potatoes 20
More than 1/3 of world cereal is consumed by livestock animals
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Comparison of number of kilograms of grain needed to produce 1 kg of live weight gain
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Over-crowded livestock operations can contribute to:
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• air and water pollution
• antibiotic resistance
• infectious diseases
Seafood is also a major protein source
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Agricultural Essentials
• Soil: mixture of rock, live and dead organisms
Essential for plant life
Exposed to the elements
Subject to human priorities
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• Water
All plants need water to grow
Too little or too much can be harmful
Salinization (accumulation of salt) can be a problem
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• Fertilizer
Calcium, magnesium, nitrogen, potassium, phosphorus are often limited or absent in soil
Adding these nutrients via fertilizer increases crop yield
Can pose human health risks
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• Energy
Farming requires lots of energy!
Fossil fuels power farming machines
Distributing fertilizers, pesticides requires energy
Food must be processed, packaged, shipped, stored, etc.
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• Pest Control
Chemical pesticides Biological controls
Can kill non-target species Insect predators
Different organisms become pests
Create resistant pests
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The Green Revolution
• Increased crop yields due to synthetic fertilizers
• Cross-breeding plants for high-yield varieties
Conventional vs. “Miracle” Wheat 31
Sustainable Agriculture
Sustainable agriculture: just and lasting food production techniques (“regenerative farming”)
• Produce sufficient food to feed the world
• Minimize/repair damage caused by destructive farming practices
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Soil Conservation
• Reduce erosion
(terracing, contour plowing, strip-farming)
• Provide groundcover (cover crops, mulch)
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Natural, Agroecological Farming
• Small scale, low-input farms
• Less fertilizers, pesticides, etc.
• Reduced erosion
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