Nutrition (EXAM C) Flashcards
What is a carbohydrate?
- macronutrient
- contains carbon, hydrogen and oxygen
- grouped as monosaccharides, disaccharides, polysaccharides
- sugars, starches and dietary fibre
What are monosaccharides?
- simple/single-form of carbohydrates
- glucose, fructose, galactose
- combine to form disaccharides
What are disaccharide?
- 2 monosaccharides come together through a dehydration reaction (i.e. remove water) - stored as fat if not burned off
Glucose + Glucose =
maltose
Glucose + Fructose =
sucrose (table sugar)
Glucose + Galactose =
lactose (milk sugar)
What are polysaccharides?
- long chains glucose molecules
- “complex carbohydrates”
- starch and cellulose (i.e. fiber) - from plants
- glycogen - from animals
What % of calories intake of carbs should you have?
- 55-60% (10% as simple sugars)
- 10% of 2000 cal diet is roughly 300g
What is the glycemic index?
- represents the effect that a particular food product has on the increase in blood glucose
- foods high in refined sugars are high glycemic
(I.e. pure sugar) - foods low in refined sugars (I.e. complex CHO)
are low glycemic
Fates of Blood Glucose:
- energy (brain, kidney, muscle)
- can be converted to liver/muscle glycogen
- stored as fat-when not burnt off
- excreted in urine
What is blood glucose?
- sugar that the bloodstream carries to all cells in the body to supply energy
How much total energy of carbohydrates is stored in the body? (muscle glycogen)
- 12 grams/kg of muscle tissue
- storage can be increased or decreased
- 360 grams or about 1440 calories
What are fats composed off?
- triglycerides, cholesterol, and phospholipids
What is a triglyceride?
- principal form of dietary fat
- composed of glycerol and three fatty acids
What is esterification?
- the process of glycerol binding with fatty acids (3)
- is the reaction of an acid with an alcohol in the presence of a catalyst
What is a saturated fatty acid?
- a type of fat in which the fatty acid chains have all or predominantly single bonds
- chains of C, H, and O that have all C double bonds bound with H+
What is a SCFA?
- short chain fatty acid with fewer than six carbon atoms
- often found in butter or dairy
What is a MCFA?
- medium chain fatty acid is a group of fatty acids with 6 to 12 C atoms obtained from edible fats such as coconut oil
What is a LCFA?
- long chain fatty acid has 14-20 carbon chain
- this can be found in meat products
What is the name of the catalyst that allows a fatty acid and glycerol to combine?
- chemical bond known as ester
- process is called esterification
Do fatty acids vary in degree of saturation?
- yes ma’am.
What is a saturated fat?
- a type of fat containing a high proportion of fatty acid molecules without double bonds, considered to be less healthy in the diet than unsaturated fat.
What is a monounsaturated fat?
- typically liquid at room temperature but start to turn solid when chilled
- lowers total cholesterol and LDL cholesterol levels
- may reduce blood pressure
- may reduce risk of heart disease, stroke, and some cancers
- avocados, olives, nuts
What is a polyunsaturated fat?
- Omega-3 and Omega-6
- O3: reduces blood clotting and inflammation and inhibits abnormal heart rhythms
- can lower blood pressure
- found in fish (3), soybeans (6)
What is linoleic acid?
- polyunsaturated essential fatty acid found mostly in plant oils
- omega-6 fatty acid
Where are alpha-linoleic fatty acids found?
- omega-3
What is linolenic?
- a liquid unsaturated fatty acid
- found in green leafy vegetables, flax, nuts and seafood
- *- two double bonds, last double bond found 6 carbons from omega end
- 18 carbon
What are the two structures of linolenic acid?
- two double bonds, last double bond found 6 carbons from omega end, 18 carbon chain length
- three double bonds, last double bond found 3 carbons from omega end, also 18 carbon chain length
What is cholesterol?
- a waxy substance found in the blood and cells and needs for synthesis of cell membranes, vitamin D, and hormones
- it is not essential in our diet; your liver naturally produces it
- only found in animal products
necessary in the formation of steroid hormones such as testosterone and bile salts
What is emulsification?
- The breakdown of fat globules which allows the enzyme pancreatic lipase to act to digest the fats into fatty acids and glycerol
- bile salts aid in the process
How much cholesterols intake is recommended?
- 500mg < 300mg
What is the borderline recommendation of total cholesterol?
- 200-240
What is the borderline recommendation of HDL?
- 40-60
What is the borderline recommendation of LDL?
- 100-160
What is the borderline recommendation of VLDL?
- 150-199
What is HDL?
- high-density lipoprotein
- blood fa that helps transport cholesterol out of the arteries, thereby protection against heart disease
What is LDL?
- low-density lipoproteins
- blood fat that transport cholesterol to organs and tissues; excess amounts result in the accumulation of deposits on artery walls
What is VLDL?
- very low-density lipoprotein
- considered a bad form of cholesterol
- contains the highest amount of triglycerides
How much fat do we need?
- Dietary fat should not fall below 10-15% of total energy intake.
- Fat is needed for energy, essential fatty acids and fat soluble vitamins
What two fatty acids are essential for our diet?
- linoleic and linolenic
What are some fat soluble vitamins?
- A, D, E, and K
What is vitamin A essential for?
- normal vision, the immune system, and reproduction.
- beta-carotene is a red-orange pigment found in plants
- think “carrots help your eyesight”
- found in animal products such as meat, fish, poultry, and dairy foods, or some vegetables and fruits
What is vitamin D essential for?
- helps regulate the amount of calcium and phosphate in the body
- needed to keep bones, teeth and muscles healthy
- The flesh of fatty fish (such as salmon, tuna, and mackerel), sunlight
What is vitamin E essential for?
- acts as an antioxidant, helping to protect cells from the damage caused by free radicals
- boost its immune system so that it can fight off invading bacteria and viruses
- found in sunflower, corn, and nuts
What is vitamin K essential for?
- play a role in blood clotting, bone metabolism, and regulating blood calcium levels
- kale, spinach, fish, eggs
What effect does alcohol have on vitamin K?
- delayed clotting, and excessive bleeding
What is a protein?
- an essential nutrient; a compound make of amino acids that contains carbon, hydrogen, oxygen, and nitrogen
- protein has the characteristics necessary to form bodily structures, enzymes and muscle tissue
- made up of amino acid chains
What are amino acids?
- building blocks of protein
- contain peptide bonds of an amino group (NH2) that can be linked to an acid or carboxyl group (COOH-) to form proteins
- 20 amino acids exist but only 9 are essential in our diet
- CANNOT be synthesized in the body
What are the nine essential amino acids?
- Histidine
- Isoleucine
- Leucine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Valine
How do amino acids work?
- All 20 amino acids must simultaneously be present for optimal maintenance of growth and function (11 of which are naturally produced in the body)
What are complete proteins?
- supply all the essential amino acids in adequate amounts
- meat, fish, poultry, eggs, milk, cheese
What are incomplete proteins?
- do not supply all nine essential amino acids
- legumes (peanuts)
What is a legume?
- vegetables, such as peas and beans, that are high in fibre and are also important sources of proteins
What is the “amino acid pool”?
- blood, liver and peripheral tissues
- glucose, glycogen and lipids
- create other new amino acids
Why is protein digestion important?
- breaks down the protein into the individual amino acids, which are absorbed and used by cells to build other proteins and a few other macromolecules, such as DNA.
What is proteases?
- an enzyme that catalyzes proteolysis, the breakdown of proteins into smaller polypeptides or single amino acids
- this occurs in the stomach and small intestine
What is the critical centre in amino acid metabolism?
- gastrointestinal tract
How long can protein digestion take?
- 1 hour to 2 days
What is the most important metabolic fate of amino acids?
- the formation of proteins
What happens to excess protein in the body?
- usually stored as fat, while the surplus of amino acids is excreted
Why can’t humans store amino acids?
- strains the liver
- bloating
What is nitrogen balance? (positive)
- positive nitrogen balance is associated with periods of growth, hypothyroidism, tissue repair, and pregnancy. This means that the intake of nitrogen into the body is greater than the loss of nitrogen from the body, so there is an increase in the total body pool of protein.
- Dietary input (grams N2 / day) = amount excreted
What is negative nitrogen balance?
- Amount excreted (grams N2 /day) > dietary input
- associated with burns, serious tissue injuries, fevers, hyperthyroidism, wasting diseases, and during periods of fasting
Nitrogen Balance can usually be maintained when consuming….
- 0.8 grams of protein per kilogram of body weight in sedentary individuals
How much protein does the average North American consume in a day?
- about 100g (too much)
What factors affect nitrogen balance?
- Insufficient caloric intake, lack of non-essential nitrogen, potassium depletion, infection or cardiac insufficiency
What is the minimum requirement of exercising individuals to maintain nitrogen balance?
-
What is nutrition?
- the science of food and how the body uses it in health and diseases
What are essential nutrients?
- substances the body must get from foods because it cannot manufacture them at all or fast enough to meet its needs; include proteins, fats, crabs, vitamins, minerals, and water
What are macronutrients?
- essential nutrients required by the body in relatively large amounts
What are micronutrients?
- essential nutrients required by the body in minute amounts
What is digestion?
- the process of breaking down foods in the gastrointestinal tract into compounds the body can absorb
What are kilocalories?
- a measure of energy content in food; 1 kilocalorie represents the amount of heat needed to raise the temperature of 1 litre of water by 1 degree celsius; commonly referred to as a calorie
What is. hydrogenation?
- a process by which hydrogens are added to unsaturated fats, increasing the degree of saturation and turning liquid oils into solid fats
- produces a mixture of saturated fatty acids and standard and trans forms of unsaturated fatty acids
What is a trans fatty acid?
- a type of unsaturated fatty acid produced during the process of hydrogenation
- have an atypical shape that affects their chemical activity
What is a whole grain?
- the entire edible portion of a grain, such as wheat, rice, or oats, consisting of the germ, endosperm, and bran
- germ and bran are often removed during milling or processing
What is dietary fibre?
- non-digestible carbohydrates and lignin that are intact in plants
What is functional fibre?
- non-digestible carbohydrates either isolated from natural sources or synthesized
- may be added to foods and dietary supplements
What is solvable fibre?
- fibre that dissolves in water or is broken down by bacteria in the large intestine
What is insoluble fibre?
- fibre that does not dissolved in water and is not broken down by bacteria in the large intestine
What are vitamins?
- carbon-containing substances needed in small amounts to help promote and regulate chemical reactions and processes in the body
What are antioxidants?
- substance that can lessen the breakdown of food or body constituents by free radicals
- actions include binding oxygen, donating electrons to free radicals, and repairing damage to molecules
What are minerals?
- inorganic compounds need in relatively small amounts for regulation, growth, and maintenance of body tissues and functions
What are free radicals?
- an electron-seeking compound that can react with fats, proteins, and DNA, damaging cell membranes and mutating genes in its search for electrons
- produced through chemical reactions in the body and by exposure to environmental factors, such as sunlight and tobacco smoke
