Class Notes Midterm #1 Flashcards
How do we describe our diet? (2)
- In terms of food
2. In terms of nutrients
The food guide from 1977
Made all groups appear to be equally important
The food guide from 1992
Created for a grade 7 level, english speaking student
Why is the rainbow significant?
Because it is proportional to the intake
EWCFG (2007)
The first food guide with recommendations for children.
Facts About Mediterranean Food Guide (5)
- Has a 3D base
- Largest category consists of things made from plants (nutritious and deeply coloured veggies)
- Fish are highly emphasized
- Wine is on their food guide (<2 for men)
- Emphasizing eating food with others (eating slower for pleasure and to relax)
Asian Diet Pyramid and Vegetarian Pyramid Facts (3)
- Exercise is emphasized first
- Plants and healthy fats
- Sweets are higher then sweets on the asian pyramid..
What do all food guides have in common?
They emphasize plant and grain products.
The Nutrients (6)
- Carbohydrates
- Proteins
- Fats
- Vitamins
- Minerals
- Dietary Fibre
Essential Nutrients
Things that the body cannot make itself.
Essential Carbs, proteins, fats, vitamins, minerals, and fibre
- Glucose
- 9 are essential and 11 can only be made if the body gets enough of the other 9
- Linoleic acid and alpha-linolenic acid
- All 13 are essential except Vit D if someone is near the sun enough
- All are essential (this course focuses on iron, calcium, and sodium)
- Fibre is essential
How do we describe our nutrient intake? (2)
- Absolute amount eaten/day (Mg, mg, g, niacin equivalent)
2. As a percentage of our total energy (kcal) eaten in a day (macronutrients)
What is the equivalent of 1 Cal?
1000 calories= 1 Kcal= 1Cal
Atwater Factors for Macronutrients
1g Carb= 4Kcal (17KJ)
1g Protein= 4Kcal (17KJ)
1g Fat= 9Kcal (38KJ)
1g Alcohol= 7Kcal (??)
DRI Values for % Energy Intake
Protein: 10-35%
Fat: 20-35%
CHO: 45-65%
Average Kcal intake in a day
2000
What happened when the media told people fat was bad?
- People cut fat and ate more carbs
- People ate lower quality foods because they were ‘low in fat’
What are the 3 trends that appear in Canadian diets?
- Canadians have a lower % of fat intake, and have approximately 30% fat from their diets, however ‘Other’ foods account for a total of 25% of total energy and 30% of total fat
- Obesity has become an epidemic
- A large % of the population isn’t eating even the minimum of their recommended portions from any of the 4 food groups
Why has overweight/obesity become an epidemic? (2)
- Lowered levels of physical activity
2. “Toxic Food Environment” or obesegenic (constant exposure to high fat and Kcal intake)
Portion Distortion
The largely increased intake of fast foods compared to 40 years ago.
e.g. soft drinks increased 62%, french fries increased 57%, and cheeseburgers increased 24%
What are the mains nutrients that are not being received enough in the diet and are leading to many chronic diseases?
Ca (milk and alt.), Fe and Zn (meat and alt. & whole grains), Folate (green leafies & orange juice), and fibre (plant origin)
3 Main Nutrition Recommendations for Canadians
- Balance: Proportion
- Variety: Dilute anything bad
- Moderation: Don’t eat too much (portion distortion)
Nutrient-based DRIs Background and Purpose
The recommendations used to be to prevent nutrient deficiencies, now its is to do that and to optimize health and prevent chronic diseases
Estimated Average Requirement (EAR)
The amount of nutrients which meet the needs of half the populations
Recommended Dietary Allowance (RDA)
The average daily nutrient amount that covers almost all healthy people in the population (98%). Can be calculated from the EAR but the EAR cannot be calculated from the RDA.
Adequate Intake (IA)
When EAR is unknown and therefore RDA cannot be set AI is used. It is the average daily nutrient level which appears to cover the needs of the population.
Tolerable Upper Intake Level (UL)
Maximum amount of a nutrient that appears safe for most of the healthy people in the population. If one were to go above the UL they may experience adverse health effects.
Findings of the ‘Health Survey’ (CCHS)
Found that many Canadians are not consuming as many nutritious foods as they are foods from the ‘other’ category. 17-28% of adults consume more than the recommended level of fat.
What does and unhealthy diet and a lack of physical activity result in? (2)
- Higher levels of obesity
2. Chronic Disease (heart disease, diabetes, and some cancers)
How many essential nutrients are there?
45 nutrients are essential for human life (anything our body cannot synthesize).
Where are fats found in vegetables and fruits?
avocado and coconut (technically french fries and onion rings..)
Where are fats found in grain products?
croissants, muffins, and doughnuts
Where are fats found in milk and alternatives?
cheese, milk (3.25%), and ice cream
Where are fats found in meats and alternatives?
nuts, seeds, bacon, and salmon
Are potatoes a high fat food?
Baked potatoes-plain is fine but with butter and sour cream the fat content increases drastically (1 Tbsp butter= 11g and sour cream as well= 13g). French fries= 8-11g of fat. Hash browns approx. 23g. Mashed potatoes with milk and butter= 9g of fat.
Triglyceride (TG)
glycerol backbone + 3 fatty acid tails (98% of fat consumed)
Important aspects of fatty acids (2)
- Chain Length: a) 2-3 carbons- short chair f.a. b) 6-12 carbons- medium chain f.a. c) 14-22+ carbons- long chain f.a. (most prevalent in the diet)
- Degree of saturation (full of hydrogens= saturated)
Formation of a Trigylceride
condensation reaction: water comes out of reaction to attach fatty acid tails
Linoleic Acid (Omega 6)
Polyunsaturated fat, 18:2n-6, essential recommended fat
Alpha-linolenic Acid (Omega 3)
Polyunsaturated fat, 18:3n-3, essential recommended fat
Naming Fatty Acids
- Count Carbons
- Count where the 1st double bond is from the methyl end
- Bond will always present as follows: double, single, single, double
Eicosapentaeroic Acid (EPA)
20:5n-3
Docoahexaenoic Acid (DHA)
22:6n-3
Symptoms of Essential Fatty Acid Deficiency (3)
- Scaly dermatitis- inflammation of the skin
- Impaired growth in children, infants, or teens
- Excess loss of water through the skin
Roles of fat in the body (4)
- insulator (keeps the body warm)
- protection (protects skeleton and vital organs)
- energy reserve (for times of dearth- energy is stored in adipose cells, reduce levels only by oxidizing/ burning fat, used as an energy reserve only if ones energy intake is less than their energy expenditure)
- precursor for other biomolecules
Made from fatty acids (2)
- eicoanoids: biological messengers
2. phospholipids
Made from cholesterol (2)
- bile acid
2. steroid hormones (this word may be different, writing was v. messy)
Hydrogenation
A manufacturing process in which trans fats are made
Purposes of hydrogenation (2)
- To transform liquid (oil) into a harder fat. This can be for spreadability and used in baking (vegetable shortening).
- To enhance the shelf-life of processed foods. Hard fat doesn’t go rancid as fast as oil does.
Rancid
When fatty acid cells are oxidized. It will smell and taste gross.
The process of fat hydrogenation (2)
- Start with oil (e.g veg oil)
…-C-C=C-C-C=C-… - Add lots of heat and pressure:
a) fully hydrogenated: …-C-C-C-C-C-C-… (hard like butter)
b) partially hydrogenated: …-C-C-C-C-C=C-…(spreadable like margarine.)
Tans Fatty Acids (TFAs)
A category of fatty acids formed during hydrogenation
Where ‘Cis’ and ‘Trans’ Bonds come from
- most naturally occurring f.a. have ‘cis’ double bonds
- hydrogenation produces ‘trans’ double bonds.
* **these are similar to saturated fats
Food Sources of Trans Fat
Minority:
. c) Vegetable oil shortening
e.g. peanut butter, most process grain products, pastry, batters, and anything deep-fried
Where are most TFAs coming from?
Baked foods: 32%, fast foods: 13%, snack foods: 9%, margarine and shortening 9% etc.
Concerns with TFAs (2)
- Significant contributor to coronary heart disease because TFAs raise LDL (bad) and lower HDL (good)
- Canadians have the highest intake in the world
Canadian Trans Fat Task Force (2006-2009)
Limited TFA to ,2% of total fat in margarine and ,5% of fat in all other foods. However, eliminating TFAs is expensive.
Digestions
Enzymatic process of food breakdown to their smallest absorbable units (e.g fatty acids, amino acids, and glucose)