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Chapter 1-18

NUTR2050 Chapter 1-18: Chapter Summaries

Course Code
NUTR 2050
Simone Holligan

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Week 1 & 2: Introduction
Chapter 1 pg 2-34
Chapter 1 Nutrition Basics
P. 2-34
Nutrition is an interdisciplinary science focused on the study of foods, nutrients, and other food constituents and
Nutrients: chemical substances in foods that are used by the body for growth and health
Principles of the science
Principle #1 Food is a basic need of humans
Humans need enough food to live and the right assortment of foods for optimal health
People who have enough food to meet their needs at all times experience food security
Gaining food in social acceptable ways
Food security : assess at all times to a sufficient supply of safe, nutritious foods
Food insecurity : limited or uncertain availability of safe nutritious foods, or the ability to acquire them in socially
acceptable ways
Principle 2 foods provide energy (calories), nutrients and other substances need for
growth and health
Most compelling reason why people eat food is to gain calories, nutrients and other substances supplied in foods
for health and growth
A calorie is a measure of the amount of energy transferred from food to the body
Because calorie is not a substance present in the food that are not considered to be nutrients
Nutrients are chemical substances in food that the body uses for a variety of functions that support growth, tissue
maintenance and repair, and ongoing health
There are 6 categories of nutrients
Essential and non-essential nutrients
Some nutrients are provided by diet while other can be made by the body
Essential nutrients: substances required for growth and health that cannot be produced, or produced in sufficient
amounts by the body. They must be obtained from the diet
Essential means required in the diet
All of the following nutrients are considered essential
Certain amino acids (the essential ones: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine,
tryptophan, and valine)
Also referred to as indispensible amino acids
Linoleic acid and alpha linolenic acid (essential fatty acids)
Nonessential nutrients: nutrients required for growth and health that can be produced by the body from other
components of the diet
Cholesterol, creatine, and glucose are exampoles of nonessential nutrients
Present in food and used by the body but they do not have to be part of our diets

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Requirements for essential nutrients
All humans require the same set of essential nutrients, but the amount of nutrients needed varies based on
Body size
Genetic traits
Lifestyle habits (smoking, drinking)
Medication use
Pregnancy and lactation
Dietary intake standards
Dietary intake standards developed for the public cannot take into account all of the factors that influence nutrient
needs, but they do account for major ones of age, gender, growth, and pregnancy and lactation
Intake standards are called Dietary Reference Intakes (DRIs)
This is the general term used for the nutrient intake standards for healthy people
Recommended dietary allowance (RDAs)
Levels of essential nutrients intake judged to be adequate to meet the known nutrient needs of practically all
healthy persons while decreasing the risk of certain chronic diseases
Adequate intake (AIs)
These are tentative RDAs. AIs are based on less conclusive scientific information than are the RDA’s
Estimated Average Requirements (ERAs)
These are nutrient intake values that are estimated to meet the requirements of half the healthy individuals in a
group. The EARs are used to assess adequacy of intakes of population groups
Tolerable upper intake levels (ULs)
These are upper limits of nutrient intake compatible with health. The ULs do not reflect desired levels of intake.
Rather, they represent total daily levels of nutrient intake from food, fortified foods and supplements that should not
be exceeded
DRIs have been developed for most of the essential nutrients and will be updated periodically
Tolerable upper intake levels
The DRIs include a table indicating levels of daily nutrient intake from foods, fortified products, and supplements
that should not be exceeded
They can be used to assess the safety of high intakes of nutrients, particularly from supplements
Standards of nutrient intake for nutrition labels
The nutrition facts panel on packaged foods uses standard levels of nutrient intakes based on an earlier edition of
recommended dietary intake levels
The levels are known as Daily Values (DVs) and are used to identify the amount of a nutrient provided in a serving
of food compared to the standard level
The % DV listed on nutrition labels represent the percentages of the standards obtained from one serving of food
Carbohydrates are used by the body mainly as a source of readily available energy
They consist of simple sugars, complex carbohydrates most dietary sources of fiber and alcohol sugars
Alcohol is closely related chemically to carbohydrates and is usually considered to be part of this nutrient category
Glucose, fructose and galactose are the most common monosaccharides
Molecules containing two monosaccharides are called disaccharides

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The most common disaccharides are sucrose, maltose, and lactose
Complex carbohydrates are considered complex because they have more elaborate chemical structures than the
simple sugars
Starches, glycogen and most types of fiber
Each type of simple and complex carbohydrates, except fiber provides four calories per gram
Fiber supplies two calories per gram
Bacteria in the large intestine can digest some types of dietary fiber
These bacteria excrete fatty acids as a waste product of fiber digestion
The fatty acids are absorbed and used as a source of energy
The total contribution of fiber to our energy intake is modest, and supplying energy is not a major function of fiber
The main function of fiber is to provide bulk for normal elimination
High fiber diets reduce the rate of glucose absorption and may help prevent cardiovascular disease and obesity
Nonalcoholic in the beverage sense, alcohol sugars are like simple sugars, except they include a chemical
component forms of alcohol sugars
Alcohol consumed as ethanol is considered to be part of the carbohydrate family because its chemical structure is
similar to that of glucose
With seven calories per gram, alcohol has more calories per gram than do other carbohydrates
Glycemic index of carbohydrates and carbohydrates in food
It is known that some types of simple and complex carbohydrates in food elevate blood glucose levels more than
do others
Such differences are particularly important to people with disorders such as insulin resistance and type two
Carb and carb containing foods are now being classified by the extent to which they increase blood glucose levels
This classification system is called the glycemic index
Carbohydrates that are digested and absorbed quickly have a high glycemic index and raise blood glucose levels
to a higher extent than do those with low glycemic index values
Diets providing low glycemic index carbohydrates have generally been found to improve blood glucose control in
people with diabetes
Additionally they reduce elevated levels of blood cholesterol and triglycerides increase levels of beneficial HDL
cholesterol and decrease the risk of developing type 2 diabetes and some type of cancer and heart disease
Recommended intake level
Recommended intake level of carbohydrates is based on their contribution to total energy intake
It is recommended that 45-65 percent of calories come from carbohydrates
Added sugar should constitute no more than 25% of total caloric intake
It is recommended that adult females consume between 21-25 grams and males 30-38 grams of total dietary fiber
Food sources of carbohydrates
Carbohydrates are widely distributed in plant foods, while milk is the only important animal source of carbohydrates
Protein in foods provide the body with amino acids used to build and maintain tissues such as muscle bone
enzymes and red blood cells
They body can use protein as asource of energy, it provides four calories per gram
Food sources of protein differ in quality, based on the types and amounts of amino acids they contain
Foods high in protein quality include a balanced assortment of all of the essential amino acids
Protein from milk cheese meat eggs and other animal products is considered high quality
Plan sources of protein with the exception of soybeans do no provide all nine essential amino acids
Recommended protein intake
DRIs for protein are shown on the inside front cover of this text
In general proteins should contribute 10-35 percent of total energy intake
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