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Chapter 1

NUTR 2050 Chapter Notes - Chapter 1: Glycemic Index, Low-Density Lipoprotein, Nutrient


Department
Nutrition
Course Code
NUTR 2050
Professor
Simone Holligan
Chapter
1

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NUTR2050 Midterm Chapter Notes
CHAPTER 1
Introduction:
- Nutrition is an interdisciplinary science focused on the study of foods, nutrients
and other food constituents and health
Nutrients: Chemical substances in foods that are used by the body for growth and health.
Food Security: Access 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
Calorie: unit of measure of the amount of energy supplied by food (aka kilocalorie, or
large calorie)
Principles of The Science of Nutrition
- These principles change little with time
Principle 1: Food is a basic need of humans
Principle 2: Food provides energy (calories), nutrients, and other substances needed for
growth and health
- Calories are not considered to be nutrients
Essential and Nonessential nutrients
Essential nutrients: Nutrients the body cannot manufacture, or generally produce in
sufficient amounts, are referred to as essential nutrients (required in the diet)
Examples: Carbohydrates, certain amino acids, linoleic acid and alpha-linolenic acid
(essential fatty acids)
Six categories of nutrients:
1. Carbohydrates – consist of single sugar molecule or multiples of sugar molecules
in various forms (Sugar and fruit, starchy vegetables and whole grain products)
2. Proteins – made up of chains of amino acids (Animal products and dried beans)
3. Fats (lipids) – components of food that are soluble in fat but not in water. More
properly referred to as lipids. Most fats are composed of glycerol attached to three
fatty acids.

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4. Vitamins – fourteen specific chemical substances that perform specific functions
in the body.
5. Minerals – consists of 15 elements found in foods that perform particular
functions in the body (milk, dark leafy vegetables and meat)
6. Water – essential component of the diet provided by food and fluid
Nonessential nutrients: present in food and used by the body but do not have to be part of
our diet
Requirements for essential nutrients: all humans require the same set of essential
nutrients but the amount of nutrients needed varies based on
- Age
- Body size
- Gender
- Genetic traits
- Growth
- Illness
- Lifestyle habits
- Medication use
- Pregnancy and lactation
Dietary Intake Standards
- Account for the major factors that influence nutrient needs (age, gender, growth
and pregnancy and lactation)
Dietary Reference Intakes (DRIs): general term used for the nutrient intake standards for
healthy people
- Have been developed for most of all the essential nutrients
Recommended Dietary Allowances (RDAs): levels of essential nutrient intake judged to
be adequate to meet the known nutrient needs of practically all healthy persons
- Specifies intake levels that meet nutrient needs of over 98% of healthy people
Adequate Intakes (AIs): tentative RDAs. AIs based on less conclusive scientific
information than RDAs
Estimated Average Requirements (EARs): nutrient intake values that are estimated to
meet the requirements of half the healthy individuals in a group. EARs are used to access
adequacy of intakes of population groups
- Should be used to examine the possibility of inadequate intakes in individuals and
within groups

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Tolerable Upper Intake Levels (ULs): represent total, daily levels of nutrient intake from
food, fortified foods and supplements that should not be exceeded
Standards of Nutrient Intake for Nutrition Labels
Daily Values (DVs): used to identify the amount of a nutrient provided in a serving of
food compared to the standard level
Carbohydrates
- Used by the body mainly as a source of readily available energy
- Consist of simple sugars (monosaccharide’s), complex carbohydrates
(polysaccharides), most dietary fibre and alcohol sugars
- Alcohol is closely related chemically and is considered to be part of this nutrient
category
- Glucose (blood sugar, dextrose), fructose (fruit sugar) and galactose are the most
common monosaccharaides
Most common disaccharides are:
- Sucrose (glucose + fructose = common table sugar)
- Maltose (glucose + glucose = malt sugar
- Lactose (glucose + galactose = milk sugar)
Complex carbohydrates
- Considered complex because they have more elaborate chemical structures
- Example: Starches (the plant form of stored carbohydrate), Glycogen (the animal
form of stored carbohydrate), Most types of fiber
- Each type of simple and complex carbohydrate (except fiber) provides four
calories per gram
- Total contribution of fiber to our energy intake is modest (around 50 calories), and
supplying energy is not a major function of fiber
**Main function of fiber is to provide “bulk” for normal elimination
- High fiber diets reduce the rate of glucose absorption (benefit for people with
diabetes) and may help prevent cardiovascular disease and obesity
- Alcohol has 7 calories per gram, more than any other carbohydrate
Glycemic Index of Carbohydrates and Carbohydrates in Foods
- Now known that some types of simple and complex carbohydrates in foods
elevate blood glucose levels more than others do
- Such differences are particularly important to people with disorders such as
insulin resistance and type 2 diabetes
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