Exam #3 Flashcards
Sources of dietary fats (animal and plant)
Animal sources:
meat, cheese, dairy
Plant sources:
vegetable oils, nuts, avocados
Benefits of lipids/fats
Provide texture, flavor, aroma to foods
Structural materials of cellular membranes
Wraps Nerve Fibers (mylin)
Help absorb fat-soluble vitamins
Insulate, cushion, lubricate
Provide energy
Excess calories of fat energy stores
convert fatty acids (by the liver) & store as triglycerides
fat energy stores, providing energy:
Adipose tissue (fat tissue) stores triglycerides 1 gram of fat = 9 kcal 1 gram or carbohydrates or proteins = 4 kcal
Triglycerides (important raw material for making ATP)
- The storage form of fatty acids
- kept in fat cells and in smaller amounts in muscle cells
- break down of a 16 carbon fatty acid = 106 ATP (X 3 fatty acids to form a triglyceride) — ATP “SUPERSTAR”
Glycogen (important raw material for making ATP)
- storage form of carbohydrates
- kept in both muscle cells and in liver cells
- One glucose generates 36 ATP molecules
3 main energy systems
The ATP-PCr system
The glycolytic pathway
The oxidative phosphorylative pathway
Energy systems and being chased by a bear
1) 1-2 seconds you use stored ATP
2) 10-15 seconds you tap into your ATP-PCr system for an all out sprinting
3) 1-2 minutes your glycolytic pathway keeps you going but at a slower pace
4) several minutes, even hours oxidative phosphorylative pathway keeps you going but at a much slower pace
OLD view on fats
eating fat makes you fat
saturated fats = coronary heart disease
Health regulatories promoted low fat products & to reduce intake of natural fats
1980’s low-fat high-carb diets recommended
CURRENT view on fats
foods naturally rich in fats (in small portions) are good for you
regulation of appetite and overall body composition.
According to Statistics Canada, the following changes have been observed between 1981 and 2009
average fat intake up from 85 g/per day to 91 g/ per day
the proportion of fat in the Canadian diet has not changed
Canadians are now eating LESS
trans fats,
saturated fats
cholesterol
In the past, Dieticians & Physicians generally recommended ______ of total kcals from Lipids
15-25%
The new recommendation is _____ of total kcals from lipids
20-35%
Health Canada’s recommendation of AMDR for lipids is ________
25-35%
Lipids are ‘_____ ____’ made up of molecules of _____ & ________
fatty acids, carbon, hydrogen
Fats are…
lipids solid at room temp (more hydrogen ions)
Oils are…
lipids liquid at room temp (less hydrogen ions)
Lipids are substances that…
do not dissolve in water
Saturated fatty acids are ___ at room temp
Solids
Unsaturated fatty acids are ___ at room temp
Liquids
Monounsaturated fatty acids
Contain one double bond along the carbon chain
Polyunsaturated fatty acids
contain two or more double bonds along the carbon chain
Omega 3 (essential fatty acid) EPA/DHA/ALA
anti-inflammatory
dilates blood vessels & reduce blood clotting
Supports brain function
Eases symptoms of depression, anxiety
Benefits vision, immune system, skin, hair
Omega 6 (linolenic acid)
Pro-inflammatory
Constricting Blood vessels & blood clotting
important for healing injuries & recovery from training
Caution in over-consuming Omega 6!
Alpha-linolenic acid (ALA)
is mostly found in plant foods. Your body can convert it into EPA or DHA, though this process is highly inefficient (used for energy)
ex) Found in many plant foods, including kale, spinach, soybeans, walnuts, and many seeds, such as chia, flax, and hemp. It also occurs in some animal fats.
Eicosapentaenoic acid (EPA)
is an omega-3 fatty acid that can reduce symptoms of depression and help fight inflammation in your body
Docosahexaenoic acid (DHA)
is very important for brain development and may protect against heart disease, cancer, and other health problems.
EPA & DHA mostly found in _______, including ____ ____ and _____
seafood, fatty fish, algae
Trans fatty acids
The orientation of hydrogen atoms around the double bond distinguishes cis fatty acids from trans fatty acids.
Most unsaturated fatty acids found in nature have double bonds in the cis configuration.
Lipids are substances that…
Do not dissolve in water
Phospholipids have a similar structure to?
Triglycerides (built on glycerol)
Phospholipids exist ________________, particularly in the _____
throughout the body, in the brain
Phospholipids participate in _________ and play an important _____________________
fat digestion, structural role in cell membranes
The body can/cannot make all the phospholipids it needs?
can
Is considered a ‘non-essential’ lipid
Phospholipids:
Allows water and fat to mix
Present in small amounts of food and in the body
Sterols in plants
Plant sterols
Help form the cell membrane of plants
Sterols in animals
Cholesterol Made in the liver, therefore it is nonessential Used to make: cell membranes Myelin Vitamin D Bile acids Cortisol, testosterone, estrogen
What are the two types of cholesterol?
LDL (low density lipoproteins) ad HDL (high density lipoproteins
LDL (low density lipoproteins)
‘bad’ cholesterol
Triglycerides
Your LDL, the unhealthy cholesterol, should be under 100 mg/dl
HDL (high density lipoproteins)
‘good’ cholesterol
Lowers triglycerides
(helps rid the body of the bad LDL cholesterol)
Your HDL, the healthy cholesterol, needs to be 50 mg/dl or more
High protein content
Examples of good lipids (unsaturated)
all plant lipids
Nuts & Seeds
Fish
Examples of bad lipids (saturated)
Dairy fat
Animal fat
Proteins have to be broken down to _______, ______ and ________, before they can be absorbed into the mucosal cells of the ____ _______
tripeptides, dipeptides and amino acids, small intestine
Mechanical digestion b(protein digestion and absorption)
Mechanical digestion of proteins starts in the mouth, continues in the stomach and the small intestine
Chemical digestion (protein digestion and absorption)
Chemical digestion of proteins begins in the stomach but most of it occurs in the small intestine
Stomach (protein digestion and absorption)
hydrochloric acid denatures proteins
polypeptide chains are more accessible for enzymatic breakdown.
stomach acid also activates the protein-digesting enzyme pepsin (breaks certain peptide bonds in the polypeptide chains – shorter polypeptides).
Small intestine (protein digestion and absorption)
polypeptides are broken into even smaller peptides and amino acids by protein-digestion enzymes produced in the pancreas and small intestine.
Lumen of the Small Intestine into the Mucosal Cells
single amino acids, dipeptides and tripeptides are absorbed.
absorbed into the mucosal cells then into the blood
USES energy-requiring amino acid transport systems.
The pancreas secretes pancreatic juice containing:
Bicarbonate: neutralizes the acid in the chyme (from the stomach)
Pancreatic amylase: digests carbohydrates into sugars
Pancreatic proteases: digests proteins into amino acids
Pancreatic lipases: digests fats into fatty acids
Gall bladder stores?
Bile
Liver secretes ____ which emulsifies fat (breaks down droplets) so ___ can access fat molecules
bile, lipases
The lymphatic system
maintains the balance of fluid between the blood and tissues, known as fluid homeostasis.
forms part of the body’s immune system and helps defend against bacteria and other intruders.
facilitates absorption of fats and fat-soluble nutrients in the digestive system
Sources of protein in animals vs. plants
Animal: meat, eggs, and dairy products. (high in saturated fat, cholesterol, and contain all 9 essential amino acids)
Plant: grains, nuts, legumes. (high in fibre, phytochemical, vitamins, minerals and unsaturated fat. Missing some essential amino acids)
Amino acids?
Amino acids are the building blocks of protein.
Contain carbon, oxygen, amino group (nitrogen), acid group and a unique side chain.
(20 different side chains make 20 different amino acids (9 are essential)
Peptide bonds - structure
Join the acidic group of one amino acid with the amino group of another amino acid
Polypeptides - structure
a chain of amino acids linked by peptide bonds — (3 dimensional shapes)
Dipeptide - 2 amino acids
Tripeptide - 3 amino acids
Proteins - structure
made of one or more polypeptide chains folded into specific three-dimensional structures
Different protein shapes:
elongated shape - collagen
(tendons and ligaments)
spherical shape - hemoglobin
(red blood cells)
linear shape - muscles
What s denaturation? And what allows it to occur?
The change in a protein’s three -dimensional shape
Occurs with:
Heat from cooking
Acidity (example: low pH in the stomach)
Mechanical agitation
Structural proteins (cells and body parts)
Cells:
Cell Membrane
Organelles
Cell Fluid (cytoplasm)
Body Parts: Skin Hair Ligaments Tendons Bones
Enzymes with protein function
Assist biochemical
Most chemical reactions in the body require enzymes
Transport other proteins in blood and across membranes
Immunity/safety - protein functions
Skin—barrier from bacteria
Blood clotting in case of injury
Antibodies protect the body from foreign invaders
i.e. vaccines stimulate these to improve immunity against disease
Protein functions (hint: 4)
Movement:
Muscle contraction
Hormones:
Regulate biological processes
Regulate fluid balance:
Maintain proper acidity of blood
Energy:
Under certain situations
Of the approximately ___ ____ of protein synthesized by the body each day, only about ___ ____ are made from ____ _____ consumed in the diet.
The other ___ ____ are produced by the _______ __ _____ ____ from protein broken down in the body.
300 grams, 100 grams, amino acids.
200 grams, recycling of amino acids
Extra amino acids ____ be stored as ______
cannot, proteins
Extra amino acids are used for _____ or stored as ___
Energy, fat
Nitrogen balance (protein)
nitrogen intake equals nitrogen loss
Ex) maintenance of body protein and weight
Negative nitrogen balance
More nitrogen loss than consumed
Ex) from illness, injury, or decreased consumption
Positive nitrogen balance
More nitrogen consumed than lose
Ex) during growth, pregnancy or weight training
RDA for protein
0.8 g/kilogram of body weight for adults
ADMR for protein
10-35%
International Society of Sports Nutrition recommends how much protein per kg of body mass
1.4-2.0
According to recent reviews, it was recommended to have how much protein
1.2-2.2 grams per kg of body mass
The upper limit of what healthy livers and kidneys can handle for protein is…
3.5 to 4.5 g/kg of body mass per day.
We should try to get ____grams of protein ____times per day
10-20, 4-6
Excess dietary amino acids can be deaminated and _______ to _____ and stored as _______ in ______ _______
converted, fatty acids, triglycerides, adipose tissue
High protein diets increased urea output
Increased demands on the kidneys
Increased loss of water from the body
Possible increased loss of calcium
Increased risk of kidney stones
High protein diets have a higher risk of:
heart disease
cancer (processed meats – linked to colon cancer)
obesity & diabetes
diverticulosis (outpouching of the colon wall)
Do’s and don’ts for plant based eating:
DO aim for about 1 gram of protein per kg of bodyweight;
add 30-40 grams each day if you are in a phase of intense training.
DO get enough fat.
DO eat a variety of whole foods– veggies and fruits!!
DON’T consume too many processed foods (including “healthy” protein powders and processed soy products).
What can soy assist in?
Lowering cholesterol (fiber)
Great sources of Omega 3 fatty acids (brain health)
Great source of protein (muscle, immune system, etc
Reduce risk of prostate cancer & breast cancer (isoflavones)
Lower blood pressure by producing nitric oxide in arteries… keeps ‘open’
Conditionally essential Amino Acids?
Under certain conditions, some of the nonessential amino acids cannot be synthesized in sufficient amounts to meet the body’s needs.
