Class Notes Before Midterm #1 Flashcards
How do we describe our diet? (2)
- In terms of food2. 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 base2. Largest category consists of things made from plants (nutritious and deeply coloured veggies)3. Fish are highly emphasized4. Wine is on their food guide (<2 for men)5. Emphasizing eating food with others (eating slower for pleasure and to relax)
Asian Diet Pyramid and Vegetarian Pyramid Facts (3)
- Exercise is emphasized first2. Plants and healthy fats3. 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)
- Carbohydrates2. Proteins3. Fats4. Vitamins5. Minerals6. Dietary Fibre
Essential Nutrients
Things that the body cannot make itself.
Essential Carbs, proteins, fats, vitamins, minerals, and fibre
- Glucose2. 9 are essential and 11 can only be made if the body gets enough of the other 93. Linoleic acid and alpha-linolenic acid4. All 13 are essential except Vit D if someone is near the sun enough5. All are essential (this course focuses on iron, calcium, and sodium)6. 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 fat2. Obesity has become an epidemic3. 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 activity2. “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 2. Variety: Dilute anything bad3. 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 obesity2. 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)2. 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 2. Count where the 1st double bond is from the methyl end 3. 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 skin2. Impaired growth in children, infants, or teens3. Excess loss of water through the skin
Roles of fat in the body (4)
- insulator (keeps the body warm)2. protection (protects skeleton and vital organs)3. 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)4. precursor for other biomolecules
Made from fatty acids (2)
- eicoanoids: biological messengers2. phospholipids
Made from cholesterol (2)
- bile acid2. 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).2. 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-…2. 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 bonds2. hydrogenation produces ‘trans’ double bonds. ***these are similar to saturated fats
Food Sources of Trans Fat
Minority: . c) Vegetable oil shorteninge.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)2. 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)
Absorption
Transfer of digested food components across the absorptive surface of GI Tract into vascular (blood) and lymphatic systems.
Metabolism
Various pathways that nutrients take following the previous 2 steps, either to be stored or to be used to make other molecules in the body.
How is fat Digested and Absorbed (7)
- Trigylcerides from food enter the small intestine2. Bile acids enter the small intestines and disperse fat into smaller droplets (emulsification)3. Lipases break down fat (sometimes some are missed)4. Formation of micelles5. F.a.’s and monoglycerides will be absorbed into intestinal wall (mucosa) a) If f.a. < 12C then absorbed into portal vein b) If f.a. > 14C then reformation of triglyceride will be packaged into chylomicron and enters the lymph system which eventually enters the vascular system at the thoracic duct6. Bile acids will be reabsorbed/ recycled
Bile Acids (3)
- Made from cholesterol in the liver (non-essential)2. Required for… a) fat emulsification b)formation of micelles3. Amounts of bile acids required each day are much larger than the amount our liver must synthesize. Therefore reabsorption is very efficient (may cycle 3-5x per meal and that would is not recycled is lost in feces)
Summary: with more soluble fibre.. (3)
- Less cholesterol absorption2. Less bile acid reabsorption: forces liver to make more bile acids from cholesterol (‘denovo’ cholesterol synthesis) or easier to take up ready source of cholesterol from blood in order to make more bile acids for digestion)3. Result: decrease in total blood cholesterol levels
Lipoproteins Function
Transport fat molecules around body via the vascular and lymph systems (blood or lymph). Only in the body, NOT made from food.-Every lipoprotein is comprise of some of these elements a) triglyceride b) cholesterol c) phospholipids d) protein-These serve as identification cards to help attach a lipoprotein to its target tissue
Risk of Coronary heart Disease (CHD) if..
< 1.03mmol/L of HDL or >3.36mmol/L of LDL
Chylomicrons (3)
-carry fat from the intestine to the lymph then to the blood to drop off the fatty acids at the adipose/ muscle-present in the blood only after meals (2-10hrs to clear out)- blood taken for cholesterol must be down when fasting
VLDL
made in the liver to carry fats (TG) that were formed from excess dietary carbs and proteins in the liver to take out to fat stores, it becomes LDL
LDL (‘bad’ cholesterol- only if blood levels are high)
Circulates blood and delivers cholesterol to all body tissues. Should return to liver for disposal when it is done. However, not taken up by liver if the liver already is well-supplied with cholesterol. Therefore LDL levels will be high.
HDL (‘good’ cholesterol- reverse of cholesterol transport0
Is make in the liver to pick up unneeded cholesterol from tissues and turn it for disposal in the liver.
What is the ‘total’ blood (or serum) cholesterol?
TC-LDL+HDL+VLDL (mmol/L everywhere, mg/dL in the US)Conversion: mg/dL= 38.67=mmol/L
Lipoproteins: Link to CHD (3)
-There is a correlation between the number of CHD deaths and the serum cholesterol that a person has-200mg/dL or 5.2 mmol/L is the cut off point- A 1% mg/dL drop in TC means a 2% lower risk of CHD **she stressed this a lot
Atherosclerosis
It is a slow gradual accumulation of cholesterol-rich plaque found in the arteries. It lower flood flow (occlusion) “hardening of the arteries.” Usually takes decades, no symptoms or obvious ways to measure it.
Thrombosis
When damage to advanced arterial plaque causes a platelet-rich blood clot formation. This is called a Myocardial Infraction (MI) or a heart attack.
Atherosclerosis: Early Stages
Patients will present with high amounts of LDL from diets which are high in saturated and trans fat. From ages 8-12+ LDL becomes oxidized and will look foreign to the immune system.
How LDL becomes oxLDL
-high in saturated and trans fat-high in dietary cholesterol
Stages before a heart attack
Atherosclerosis > ‘injury’ > Thrombosis
Steps in reducing/ eliminating CHD (4)
- Soluble Fibre (to keep LDL low)2. Antioxidants (to keep LDL from being oxidized) -get these from the diet and NOT from tablets3. Injury Prevention (avoid toxins, stay physically active)4. Fish Oils (EPA) (shown to lower platelet aggregation)
Role LDL in CHD
If not taken up by the liver, LDL will accumulate in artery. LDL > oxLDL which attracts macrophages (immune cells)The oxLDL being taken up by immune cells into the arterial wall ultimately leads to Atherosclerosis.
Level of HDL in CHD
Raises blood levels which means that high amounts cholesterol can be removed from tissues for disposal in the liver. This is considered to be ‘reverse’ cholesterol transport which = less plaque buildup
How to increase HDL levels? (6)
- Exercise (aerobic)2. Avoid dietary supplements promising to rais HDL3. Lose eight (only if truly overweight) -10 pounds lost = HDL increase by 2mg/dL4. Limit refined carbs and sugars (they lead to metabolic syndrome which lowers HDL an raises TG)5. Don’t smoke (it lowers LDL)6. Moderate alcohol intake
How saturated fats influence blood lipoprotein levels (TC, Blood LDL, Blood HDL, and examples)
-Raises TC-Raises LDL-Does nothing to HDL-Can be found in fatty meats, full fat dairy, coconut oils, and palm oils
How polyunsaturated fatty acids (linoleum and alpha-linolenic acid) influence blood lipoprotein levels (TC, Blood LDL, and Blood HDL)
-Lowers TC-Lowers LDL-Lowers HDL
How monounsaturated fatty acids (oleic acid) influence blood lipoprotein levels (TC, Blood LDL, and Blood HDL)
-Lowers TC-Lowers LDL-Does nothing to HDL
How trans fats influence blood lipoprotein levels (TC, Blood LDL, Blood HDL, and examples)
- Raises TC- Raises LDL- Lowers HDL- margarines and shortening
How oxidization occurs membranes or in oil
In cell membranes or in oil: double bonds in fatty acids are vulnerable to a free radical attack. A free radical steals an electron from a PUFA making it an oxidized fat.
LDL oxidization (LDL, HDL, chylomicron, VLDL. They all have triglycerides, PL, proteins, and cholesterol)
LDL: Cholesterol rich. -Elevated in liver stops taking back the LDL from the blood. -As long as LDL is regularly cleared from the blood by the liver oxidization is low.-If free radical comes and takes an electron then it will be oxidized
Antioxidants
Naturally occurring: vitamins C, E, B-carotene, SE, Fe, and minerals.
Stages of Cancer
First there is DNA damage (from UV rays, retro-viruses, and free radicals) 1. Initiation: When DNA damage enters a normal cell body2. Promotion: assisting division of a damages cell3. Progression: accumulation of errors and mutating4. Metastasis: when this spreads
Initiation and Promotion
DNA is damages > free radicals lead to oxidization > this leads to a damaged cellPUFA > short chain aldehydes
Oxidization Summary (3)
Free Radical Damage:a) DNA INITIATIONb) Fat -LDL > oxLDL > atherosclerosis -Body cell membranes: PUFA > PUFA + electron (then PROMOTERS) > short chain aldehyde (malondialdehyde)c) Proteins (cataracts in eyes)
Dietary Cholesterol (5)
- Structural component of all animal and human cell membranes.2. Precursor of: a) bile acids b) vitamin D c) steroid hormones3. Present only in foods of animal origin4. Body makes cholesterol (not an essential nutrient)5. Most recent DRI report: Cholesterol consumption as low as reasonable (Last updated September 2002)
Examples of foods containing DIETARY cholesterol
(in order) Eggs, beef, pork, chicken, turkey, shrimp, cheddar cheese, ice creme, and milk
Summary of Dietary Strategies to lower total serum cholesterol in order of effectiveness (3)
- Lowers total saturated and trans fatty acid intake2. Raise soluble fibre intake3. Lower dietary cholesterol intake (step #1 helps with this)
EPA equation
20:5n-3
DHA Equation
22:6n-3
Fish oils contain?
EPA and DHA
EPA and DHA
Originate from phytoplankton, consumed by marine (ocean) fish > also found in lakes therefore EPA and DHA are in lake fish too!
Where did interest in fish oils originate? (3)
In the 1970 scientists noticed that the Greenland Eskimos had:1. Very high intake of fish and marine mammal blubber2. They had lower risk of CHD3. Their blood clotting ability is somewhat lower then others. (they may be likely to have atherosclerosis but they were less likely of developing thrombosis)
Examples of fish that are high in fats
Salmon, Mackeral, Herring, and Sardines
EPA: Potential in Heart Health (5)
- EPA does NOT work to lower blood cholesterol or LDL2. Lowers blood levels or serum concentrations of TG3. Lowers platelet stickiness or reactivity 4. Lowers blood pressure5. There are 15 others mentioned in text.
Example of Platelet stickiness
Fatty acids arachidonic acid (20:4n-6) converts to an icosanoid (thromboxane A2). If it is a fatty acid then EPA turns to thromboxane A3 which has a more moderate platelet response.
What is the ratio of omega 6’s and 3’s that humans should be having?
10x the Omega 6s as Omega 3s
What is the ratio of omega 6’s and 3’s that Canadians are currently having?
17x the Omega 6s as Omega 3s
What is the goal that we should be striving for in regards to Omega 6s and 3s?
To narrow the gap between Omega 6s and 3s. Not to have a lower amount of Omega 6s to Omega 3s.
DHA helps in..?
Retinal development and brain development
Fish oil supplements? (3)
- Try cod, pickerel, or haddock as they have a less ‘fishy’ taste.2. Fish Oil supplements3. Higher alpha-linolenic
Things to watch out for with fish oil supplements (5)
- Pure oil: 9kcal/g2. Full of double bonds (how dedicated was the manufacturer)3. Contaminants4. Higher doses are to known to lead to higher risk of bleeding or hemmoragic stroke (blood vessel in the brain bursts)5. Higher blood sugar in diabetics
Where else does alpha-linoleic acid come from?
walnuts, flax, canola oil, wheat germ, DHA-rich micro-algae, DHA-rich eggs
Alpha-linoleic acid
<5-10% of EPAs come from 18:3n-3. 3% of DHAs come from 18:3n-3 being converted to from EPA to DHA. (This should be double checked..)
Fish and fish oil recommendations from EWCFG and AHA
- EWCFG -2 food guide servings/week2. AHA -eat fish 2x/week if healthy -1g mixed EHA and DHA from doctor supervision -supplements only if necessary
Way to avoid contaminants in fish (4)
- Enjoy a variety of fish and seafood2. Limit intake of ‘top of the food chain’ fish (shark, swordfish, tuna steak, marlin)3. Eat fish lower in mercury 4. Tuna (white albacore)
White albacore serving sizes
-women who are or may become pregnant: 4 fg servings/week-children ages 1-4: 1 fg serving/week-children ages 5-11: 2 fg servings/week-Albacore as a main protein source: 10 fg servings/week
What are the health risks of not consuming fish and/or their oils?
Higher amounts of coronary heart problems if there isn’t enough fish in the diet. The benefits of eating fish outweigh the costs.
What are the 10 leading causes of death?
cancer, heart disease, and strokes
What are the main cancers found in north american males?
lung, prostate, and colorectal
What are the main cancers found in north american females?
lung, breast, and colorectal
Describe the relationship between fats and cancer (3)
- Differs around the world2. Overall mechanisms that link fat and cancer are unknown3. a) difficulty in separating fat intake from total energy intake b) effects of total fat. Does increase in fat equal an increase in cancer? c) is there effects of different fatty acid types?
Dietary factors of fats and cancer (what we do know)
-they account for 30-40% of all cancers-lower fat diets decrease cancer risk-higher fibre diets reduce risks of cancer-higher intake of plant based food reduce the risks of cancer (e.g. cruciferous veggies, fruits, whole grains, legumes)
Dietary lifestyle factors of fats and cancers (what we do know)
-smoking increasing risks-being physically active decreases risk-maintaining a healthy body weight decreases risk-being exposed to hazardous environmental factors increases risk (espestis and farmers lung)
Total fat DRI recommendations from 1990-2002
1990: < or = to 30%2002: 20-30% (in Japan 10-15% and in the mediterranean 40%)
Saturated DRI recommendations from 1990-2002
1990: < or = to 10%2002: As low as possible (AHA recommends < or = to 7%)
Trans DRI recommendations from 1990-2002
1990: very little discussion2002: as low as possible (AHA < or = to 1%)
Monounsaturated fatty acid DRI recommendations from 1990-2002
1990: should comprise the majority of fat intake2002: stayed the same
Polyunsaturated fats (alpha linoleic and linolenic) DRI recommendations from 1990-2002
1990: < or = to 10% taken together2002: alpha linoleic (0.6-1.2% of the diet) linoleic (5-10% of the diet) ***this stresses the 10/1 ratio
Naturally occurring oils are…
A combination of all fatty acids, no naturally occurring oil is only 1 type of fatty acid
Summary of the DRI values
EAR (half the pop) -> RDA (98% of healthy pop)AI (Daily value given if EAR is unknown)UL: The amount you can have without having any adverse effects
Categories of fats summary
Saturated= <10%MUFA= Majority of your fat intakeTrans= low as possible
Lumen
Blood flow
Which is an organic compound? a) calciumb) waterc) vitamin Cd) salt
c) vitamin C
Which of the following is NOT closely linked to dietary factors?a) pneumoniab) strokec) heart diseased) cancer
a) pneumonia
Which of the following foods is the most ‘nutrient dense’?a) potatob) onionc) cornd) broccoli
d) broccoli
Which of the following is 1 food guide serving? a) 1 cup fo cooked riceb) 1 cup of fortified soy beveragec) 1/2 cups of cooked beansd) 1 cup of orange juice
b) 1 cup of fortified soy beverage
Which of the following food groups us part of the EWCFG (2007)?a) breads and cerealsb) milk productsc) fruits and vegetablesd) meat and alt.
d) meat and alt.
Food Groups for EWCFG (2007)
Vegetables and FruitGrain ProductsMilk and AlternativesMeat and Alternatives
Cancer risk is attributed to..
40-50% tabacco30-40% dietary choices10% genetic reasons
Which of the following is an essential amino acid?a) glycineb) methioninec) alanined) glutamine
b) methionine
Highlights from ‘trends’ in Canadian/North American eating habits
Higher servings of other foods (fats and sugars have gone up)Lower serving from the four food groups
According to the DRI recommendations, the RDA for vitamin C for men ages 19-30 is 90 mg/day therefore the EAR is 45mg/day? (T/F)
False
According to the DRI recommendations, the RDA for vitamin C for men ages 19-30 is 90 mg/day therefore a 25 year old man consuming 80mg/day is at risk of scurvy? (T/F)
False
According to the DRI recommendations, the RDA for vitamin C for men ages 19-30 is 90 mg/day therefore a 29 year old man consuming 120mg/day may develop osmotic diarrhea? (T/F)
False
Which are legumes and which are nuts?peanuts, walnuts, pinto beans, pecans, chickpeas, lentils, and almonds
Legumes: peanuts, pinto beans, chick peas, and lentilsTree nuts: walnuts pecans, and almond
How to tell if there is trans fat in your kitchen?
If the fat percentages do not add up
Which is a product of digestion?a) triglyceridesb) bile acidc) free fatty acidsd) lipase
c) free fatty acids
The lipoprotein most enriched in protein is..a) VLDLb) HDLc) LDLd) Chylomicron
b) HDL
Eating a diet rich in _______ may help keep both blood TC and LDL within healthy levels and reduce CHD risk.a) ironb) cholesterolc) ‘goog’ cholesterold) soluble fibres
d) soluble fibres
