jimtrue.com : school : HS1322 : CH01: Introduction to Nutrition

Posted by Jim True on October 7, 2009 11:27 AM. Last Updated October 7, 2009 11:27 AM

Disclaimer for all material noted here is at the bottom of this web page.

CH01: Introduction to Nutrition

Dr. Allaithy (Ah-LAY-thee)

Learning Objectives: Chapter One

1. Identify factors that influence food selection
2. Define nutrition, kilocalorie, nutrient and nutrient density
3. Identify the classes of nutrients and their characteristics
4. Describe four characteristics of a nutritious diet
5. Define Dietary Reference Intakes and explain their function
6. Compare EAR, RDA, AI, and UL
7. Describe the processes of digestion, absorption, and metabolism
8. Explain how the digestive system works
9. Distinguish between whole, processed and organic foods
10. Compare how a meat-based or plant-based diet impact the environment

Factors Influencing Food Selection

• Flavor
• Taste
• Smell
• Appearance
• How it feels in the mouth
• Texture
• Temperature
• Other Aspects of Food
• Cost
• Convenience
• Availability
• Familiarity
• Nutrition
• Demographics
• Age
• Gender
• Educational level
• Income
• Culture and Religion
• Traditional foods
• Special events/celebrations
• Religious foods/practices
• Health
• Health status
• Desire to improve health or appearance
• Nutrition knowledge and attitudes
• Social and Emotional Influences
• Social Status
• Peer pressure
• Emotional status
• Food associations
• Food Industry and the Media
• Food industry
• Food advertising
• Food portrayal in media
• Reporting of nutrition/health studies
• Environmental Concerns
• Use of synthetic fertilizers and pesticides
• Wastefulness of fattening up livestock/poultry

Definitions

• Nutrition is a science that:
• studies nutrients and other substances in foods and in the body and how these nutrients relate to health and disease, and
• explores why you choose particular foods and the type of diet you eat
• Nutrients
  • Nourishing substances in food that provide energy and promote the growth and maintenance of your body
• Kilocalories
• a measurement of the energy in food
• 1 kilocalorie raises the temperature of 1 kilogram of water 1 degree Celsius
• Also called a Calorie
• Abbreviated as Kcalorie or kcal
• When you hear "calorie", it is really a kilocalorie
• The number of kilocalories you need is based on 3 factors:
• Basal metabolism: (about 2/3 of total energy needs for individuals who are not very active), at rest or resting metabolism
• Physical Activity
• Thermic effect or specific dynamic action of foods: (5 to 10% of total energy needs) - 3: digestion, absorption and metabolism
• Digestion
• Absorption
• Metabolism: the chemical process by which nutrients are used to support life

BMR (Basal Metabolic Rate) depends on factors such as:

• Gender - males and females; men are higher because they have more muscle tissue
• Age - older you get, the metabolic rate goes lower, past 40
• Growth - increase your metabolism the more you grow
• Height - the taller you are the more body mass
• Temperature - hotter increase, colder increase
• Fever and stress - increase energy needs, increase metabolism
• Exercise - increase
• Smoking and caffeine - increase
• Sleep - decrease

Classes of Nutrients - Overview

• Carbohydrates - primary source of energy
• Proteins - secondary source of energy
• Lipids (fats) - last source of energy
• Vitamins
• Minerals
• Water: 50-60% water

Carbohydrates

• A large class of nutrients, including:
• Sugars
• Starches
• Fibers
• That function as the body's primary source of energy

Lipids (Fats)

• A group of fatty substances, including triglycerides and cholesterol, that
• Are NOT soluble in water
• provide a rich source of energy and structure to cells

Proteins

• Major structural parts of body's cells that are made of nitrogen-containing amino acids assembled in chains
• Particularly rich in animal foods - MAIN SOURCE
• Present in many plant foods

Vitamins and Minerals

Main difference is vitamins are ORGANIC, MInerals are INORGANIC. Organic means containing Carbon

• Vitamins: Noncaloric, organic nutrients found in a wide variety of foods that are essential to:
  • regulate body processes
  • maintain the body
  • allow growth and reproduction
• Minerals: Noncaloric, inorganic nutrients found in a wide variety of foods that are essential to:
• regulate body processes
• maintain the body
• allow growth and reproduction

Water

• Inorganic nutrient that plays a vital role in all bodily processes and makes up just over half of the body's weight

Functions of Nutrients

• Provide energy: Carbohydrates, Lipids, Proteins
• Promote Growth and Maintenance and regulate body processes: all but Carbohydrates

Food Facts

• Most foods provide a mix of nutrients
• Food contains more than just nutrients: food may contain colorings, flavorings, caffeine, phytochemicals (aroma) and other substances

Energy Yielding Nutrients

• Carbohydrates: 4 kcal/gram
• Lipids: 9 kcal/gram
• Proteins: 4 kcal/gram

More Vocabulary

• Micronutrients - Vitamins
• Macronutrients - Carbohydrates, Proteins, Lipids
• Organic nutrients - Vitamins [Carbohydrates, Proteins, Lipids]
• Inorganic nutrients - Minerals, Water

Essential Nutrients

Nutrients that either cannot be made in the body or cannot be made in the quantities needed by the body; therefore we must obtain them from food.

• Examples: Glucose, vitamins, minerals, water, some lipids, and some parts of protein

Nutrient Density

• Which food is more nutrient dense? Cola or Milk: Milk! Cola is empty calories
• Nutrient Density: a measure of the nutrients provided in a food per kcalorie of that food
• Empty-KCalorie foods: provides few nutrients for the number of kcalories they contain

Characteristics of a Nutritious Diet

• Adequate: provide enough KCal, essential nutrients and fiber to keep the person in good health
• Balanced: eating more servings of nutrient dense foods and fewer servings of empty calorie foods
• Moderate: no excess of kcal
• Varied: different sources of nutrient dense foods

Dietary Reference Intakes (DRI) - KNOW!

• Recommended Dietary Allowance (RDA): intake value sufficient to meet nutrient requirements of 97-98% of all healthy individuals in a group
• Estimated Average Requirement (EAR): Intake value estimated to meet requirement of half the healthy individuals in a group
• Adequate Intake (AI): Intake value used when a RDA cannot be based on an EAR because there's not enough scientific data
• Tolerable Upper Intake Level (UL): Maximum intake level above which toxicity would increase
• Estimated Energy Requirement (EER): The dietary energy intake measured in kcal that is needed to maintain energy balance in a healthy adult
• There is no RDA of Upper Intake Level for kcalories because these concepts do not apply to energy and would lead to weight gain
• RDA and AI - useful in planning diets for individuals
• EAR - useful in planning diets for groups
• Age group: 1-3 Carbohydrates 45-65%, Fat 30-40%, Protein 5-20%
• Age group: 4-18 Carbohydrates 45-65%, Fat 25-35%, Protein 10-30%
• Age group: over 18 Carbohydrates 45-65%, Fat 20-35%, Protein 10-35%

Digestion, Absorption and Metabolism

• Digestion: Process by which food is broken down into its components in the gastrointestinal tract with the help of digestive enzymes
• Absorption: The passage of digested nutrients through the walls of the intestines or stomach into the blood or lymph, where they are transported to the cells
• Metabolism: All the chemical processes by which nutrients are used to support life, includes anabolism (building up of substances) and catabolism (breaking down of substances)

Mouth - Oral Cavity

• tongue and teeth help chew food (32 teeth)
• Saliva contains digestive enzymes and lubricates the food to move further along GI (gastrointestinal) tract
• Tongue rolls chewed food into bolus

From Mouth to Esophagus

• When swallowing, the epiglottis covers the tubes to the lungs so that food does not get into the lungs
• The bolus moves from the mouth through the pharynx to the esophagus
• What is peristalsis? involuntary muscle movement that moves the food through the gastroinstestinal tract

Stomach

• Food passes from the esophagus through the LES (Lower Esophageal Sphincter) into the stomach
• Mucous membranes secrete hydrochloric acid
• Chyme
• Pyloric sphincter
• Average 1 1/2 - 4 hours in stomach, 6-8 hours in small intestine, 18-24 hours in large intestine
• Stomach holds 2 cups at a time

Small Intestine

• 15-20 feet long
• Duodenum - first foot of small intestine - much digestion and absorption goes on here
• Bile - fat digestion, made in lived, stored in gall bladder
• Most nutrients pass through villi & microvilli into blood or lymph vessels -> transported to liver -> body

Large Intestine

Connects small intestine to the rectum
• About 5 feet long
• Receives waste products of digestion and passes them on to rectum
• Absorbs water, some minerals, and a few vitamins (such as vitamin K - used for blood clotting) made by bacteria residing there

Food Facts

1. Whole Foods - food not processed prior to eating, can be grown with pesticides and chemicals
2. Organic Foods - foods grown without use of pesticides or chemicals
3. Processed foods - cooking, preserving or doing something to the food prior to eating
4. Enriched foods - adding nutrients not already in them
5. Fortified foods - adding more nutrients than what the item already has in them

Organic Foods

• Organic food is produced without using most:
• Conventional pesticides
• Petroleum-based fertilizers or sewage sludge based fertilizers
• bioengineering
• ionizing radiation (irradiation)

Homework: Name and date of today, due next week 10/6, handout provided

Disclaimer: These are MY notes taken from classroom lectures while I'm in the classroom. While I'm perfectly happy to share my notes with my classmates and I know I take very good notes, you should still make every effort to attend the class and TAKE YOUR OWN NOTES. I will not transcribe everything the instructor says in the classroom, and I will NEVER post pre-exam reviews. My notes will not replace the value of actually attending class and taking your own class notes.I also cannot attest to their accuracy, other than they are what was provided in the lecture; you should not reference my notes as "expert opionion" by any means, and if you notice an error or omission, please do me the favor of e-mailing me with the correction and I will re-post my notes. End of Disclaimer.