Mans Food Exam 2
Phytate
(in whole grains and cereals) binds calcium to zinc, making them unavailable for absorption.
Hereditary Hemochromatosis
(iron overload), a genetic disorder in which a person absorbs too much iron. Can lead to an accumulation of iron in the pancreas, heart, and liver, and it can cause diabetes, heart failure and liver problems if left untreated
---Vitamin C
(or ascorbic acid) Water-soluble vitamin found in citrus fruits (limes, lemons, grapefruits) and veggies. British sailors realized that eating limes would prevent scurvy which is a vitamin C deficiency.
Gynoid body fat
(pear-shaped). ppl w this body fat distribution pattern store most of their body fat in the hips and thighs. Most common in women
TEF
(thermic effect of food), the calories burned as you digest, absorb, store, transport and metabolize food. On avg, the thermic effect of food burns 10% of the calories ingested, no matter what the food source is.
Mechanisms for lipid oxidation
-exposure to catalytic metals -exposure to UV light -exposure to visible light -exposure to heat -exposure to enzymes -exposure to ozone
LDLs
Low-density lipoproteins, once VLDLs deliver triglycerides to the tissues they become LDLs, which are cholesterol-rich. They deliver cholesterol to the other tissues.
Metabolism
a broader concept that refers to the sum of all of the biochemical reactions in the body. Includes catabolic reactions (break down molecules) and anabolic reactions (build muscles).
trans isomers (trans fatty acids)
a category of lipids. unhealthy fatty acids that are produced in the process of hydrogenation, in which hydrogen atoms are added to unsaturated fatty acids to reduce the # of double bonds in those fatty acids. This turns the fat into a solid, makes it less susceptible to spoiling, and typically delivers a preferable texture and taste, but it creates trans fatty acids as a result. cause high cholesterol and risk of heart disease have hydrogen bonds on opposite sides of the double bond. These don't cause nearly as much "kinking" in the fatty acid as cis double bonds, so they're straighter molecules that pack together better and are thus likely to be more solid than cis-forms.
common saturated fatty acids found in food are
butyric acid (4:0), lauric acid (12:0), palmitic acid (16:0), and stearic acid (18:0).
Calcium and muscle and nerve
calcium initiates the contraction of muscle cells, and it triggers the release of neurotransmitters during nerve impulses. Also affects membrane potential through regulation of the movement of sodium and potassium ions.
Calcium and blood clotting
calcium is required to convert prothrombin to thrombin, which is enzyme that converts fibrinogen to fibrin during blood clotting
Calcium and metabolism
calcium regulates the impact of hormones; it acts as a second messenger in signal transduction pathways. Also plays a role in the activation of enzymes
Interesterification is different from partial hydrogenation in that
interesterification produced no trans fatty acids
---Vitamin K
involved in the production of fibrin a protein that forms blood clots. Also required for the proper formation of some important bone proteins. Can cause problems w blood clotting and bone hardening. Good sources are leafy veggies, brussel sprouts, and broccoli, but the major source of vitamin K is the bacteria in your gut that synthesizes it.
Total energy expenditure
is equal to the sum of their REE (resting energy expenditure), physical activity and thermic effect of food (TEF)
Partial hydrogenation
removes some but not all of the double bonds in an unsaturated fatty acid. contain trans fats
Why is cancer associated with fats?
research shows diets extremely high in saturated fats can put a person at higher risk of some cancers. omega-3 polyunsaturated fatty acids may reduce the risk of various kinds of cancer
Polypeptide
the chain of amino acids that results from successful dehydration reactions. These polypeptides (which can be thousands of amino acids long) will eventually fold to form the final functional protein.
Amino acid pool
the group of free amino acids available in the cells and in the blood for protein synthesis in the short term. The body has no long-term storage mechanism for amino acids, so amino acids that are not used throughout the day are removed in a process called deamination.
Chyme
the liquid mixture of food and stomach acid, highly acidic. neutralized by bicarb once it enters the duodenum.
Bolus
the mixture of food and saliva. When a person swallows bolus it moves through the pharynx and esophagus to the stomach. Swallowing food triggers peristalsis, the muscular movement that moves food through the GI tract.
acetyl-CoA
the molecule that is fed into the citric acid cycle, which produces a small amount of ATP through substrate level phosphorylation.
The more kinks a fatty acid has the...
the more double bonds in the chain, the less is can "pack in" and the lower the melting point
Aerobic metabolism
the most efficient energy-producing pathway, produces a large amount of ATP in the presence of oxygen.
Hunger
the physiological mechanism that dictates when we eat and how much we eat
Why is consuming oxidized lipids dangerous?
the products of lipid oxidization- advanced lipid oxidation end products (ALEs)- may oxidize lipoproteins in the blood, cause inflammatory responses, and injure the liver, kidney, lung, or gut. If a food item smells bad, throw it away.
What gives triglycerides their observable characteristics? What are some examples?
their spatial arrangement; melting point and physical appearance at room temperature
Polyunsaturated fats (omega-3 and omega-6 fats) are important because
they can be enzymatically converted to other useful polyunsaturated fats via elongation and desaturation.
Termination of lipid oxidation
third step of lipid oxidation, the chain reaction of radical formation ends when two radicals react and produce a non-radical. This process can be sped up by antioxidants such as vitamin E and vitamin C.
Why is consumption of conjugated fatty acids a health concern associated with lipids
this caused people to feel "fuller" after eating and may reduce body fat and risk of certain cancers in women. Also associated with lower cholesterol and LDL. fatty acids may have conjugated double bonds instead. low levels of fatty acids with conjugated double bounds are found in dairy products. One noteworthy conjugated fatty acid is CONJUGATED LINOLEIC ACID (CLA), an omega-7 fatty acid found in dairy products and dietary supplements
What is the purpose of metabolism and cellular respiration?
to store energy in the form of ATP (adenosine tri phosphate) which is the "universal energy currency" of the cell.
Why is consumption of trans fats a health concern associated with lipids
trans fats is associated with the development of coronary heart disease and other health problems. trans fats are the product of partial hydrogenation of oils.
The food industry has been reducing the use of ____ since the early 2000s and the FDA is set to remove ____ from their "Generally recognized as safe" (GRAS) list by 2018
trans fats; partially hydrogenated oils
Triglycerides are also called
triacylglycerols or TAGS
Chylomicrons
type of lipoprotein made in the cells lining the small intestine after the body has absorbed fat. They assist in transportation of fats to the liver.
_______ have a greater potential for oxidation than ______
unsaturated fats; saturated fats
Vegetarian differs from vegan in that
vegetarians choose not to consume animal flesh but may eat eggs and dairy products.
Digestion and absorption of vitamins
water-soluble vitamins can be directly absorbed into the bloodstream and they don't require food to be transported in the blood. Fat-soluble vitamins (A, D, E, and K) have to be transported into the lymph by chylomicrons before they can enter the bloodstream.
Fats (or lipids) dont dissolve in _____ but dissolve in organic solvents such as _____ or ______
water; ether or acetone
dehydration reactions
when a covalent peptide bond is formed between two amino acids and a water molecule is released as a byproduct.
Conditionally essential amino acids
when the body is unable to produce nonessential amino acids in adequate amount so they must be consumed in the diet.
Glycolysis
where glucose is converted to pyruvate. a catabolic reaction.
Sigmoid colon
where indigestible matter passes through to the rectum where it remains until its discharged via anus.
Conjugated double bonds
where single bonds and double bonds alternate and are not separated by two or more methylene groups. These can occur in milk and dairy products, and they're typically produced by biohydrogenation in the rumens of certain animals like cows and deer.
Electron transport chain
where the majority of ATP production occurs for glucose.
Crystallization determines.... A more crystalline structure...
whether the food item containing the triglycerides is solid or liquid; is more solid.
Protein-based fat substitutes
whey and modified egg whites are often used in frozen desserts. they require high cooking temperatures, which can denature the proteins and take away from their nutritional value.
---Major function of Vitamin A
-Eyesight. Long term vitamin A deficiency can lead to irreversible damage called xerophthalmia, which can cause permanent blindness due to damage to the cornea. Vitamin A slows the progression of macular degeneration. eat carrots. -Disease resistance: Vitamin A is important for the formation of white blood cells and for maintenance of the epithelial lining of the GI tract, skin and lungs. Also required for cell differentiation. Deficiency negatively impacts the immune system and inhibits disease resistance. -Gene regulation:Retinoid acid plays the most significant role, -Bone development and growth: plays a role in bone remodeling and vitamin A deficiency in children can lead 2 stunted growth. -Others: plays role in reproduction, cell membrane stability, epithelial integrity, production of red blood cells, production of thyroid hormone, maintenance of the lining of the nerves, and synthesis of cortisol by the adrenal glands.
Fat cells store fat-soluble vitamins which are ______ and they play important roles in the body such as
-Vitamin A: plays a role in vision and proper immune function -Vitamin D: enhances absorption of iron and calcium (sunlight, which reacts w cholesterol to produce vitamin d in the skin) -Vitamin E: acts as an enzymatic regulator and antioxidant -Vitamin K: maintains bone health and plays a role in blood clotting
A food item that is labeled "fat free" must have less than ______ of fat per serving, and no ____ or _____ can be added to the food item during processing
.5 grams; fat or oil
---Main functions of Vitamin D
1. Bone development and maintenance: most important role, deficiencies can cause rickets in kids (softening and deformity of long bones, bowlegged) and osteomalacia in adults (softening of bones due to decalcification) 2. Calcium and phosphorous metabolism: promotes calcium absorption in the small intestine by triggering production of a calcium-binding protein called calbindin. Also causes bones to release more calcium and the kidneys to reduce urinary excretion (thus conserve calcium) when calcium levels are low. 3. Gene regulation: like vitamin A, vitamin D plays a role in gene expression and cell differentiation.
Health issues associated w lipids
1. Consumption of saturated fats 2. consumption of medium-chain fatty acids 3. consumption of conjugated fatty acids 4. consumption of trans fats 5. consumption of oxidized fats
Two forms of iron
1. Heme iron (organic form, which has a complex ring structure and is found in hemoglobin), the body absorbs heme iron more readily than non-heme 2. Non-heme iron (the elemental form)
Strategies to improve vitamin A deficiency
1. Improve diet 2. Fortification 3. Supplementation 4. Biofortification 5. Encouraging breast feeding
Process of lipid oxidation
1. Initiation: a catalyst produces a fatty acid radical 2. Propagation: the fatty acid radical reacts with molecular oxygen, producing a peroxyl-fatty acid radical which is unstable and reacts with another free fatty acid radical, producing a lipid peroxide and a different fatty acid radical which can continue the reaction in the same way. 3. Termination: the chain reaction of radical formation ends when two radicals react and produce a non-radical. This process can be sped up by antioxidants such as vitamin E and vitamin C. the end products are "secondary products" such as aldehydes, ketones, alcohols, and carboxylic acids. These often produce foul odors and tastes
Two forms of PEM
1. Marasmus: when starvation produces emaciation or a skeletal appearance. common in impoverished children, cancer/HIV patients and anorexia. 2. Kwashiorkor: means "the sickness of the weaning" in Ghana. Condition in which children have a swollen abdomen. occurs most often in kids who transition from breast milk to high-starch, low protein cereal. they get enough calories but not enough protein.
Two ways of diagnosing hemoglobin levels
1. Measuring hemoglobin levels: really tests for anemia not iron levels. 2. Measuring ferritin levels: best, most direct way to determine whether a person has an iron deficiency.
the two main arrangements of the double bonds of fatty acids are
1. Methylene-interrupted double bonds 2. Conjugated double bonds
Consequences of vitamin A deficiency
1. Night blindness 2. Keratomalacia 3. Impaired growth 4. Higher child mortality 5. Impaired immunity 6. Hearing loss 7. Higher infant mortality 8. Higher mortality of mothers most common in poor countries around the equator particularly in asia, africa, and certain parts of south america.
Three health problems associated with fats are
1. Obesity 2. Heart disease 3. Cancer
Where is iron in the body?
1. Oxygen-carrying proteins: approximately 65% of the iron in the body is found in hemoglobin, a tetrameric protein involved in oxygen transport. Approx 10% of iron is in myoglobin, an oxygen carrying molecule found primarily in muscle tissues, 2. Storage proteins: approx 20% of the iron in the body is stored in the form of ferritin, an iron-storage protein that looks like a jelly donut hole with an iron filling. A single ferritin protein can store as many as 4,500 iron atoms. Men have more of these which is why they have more iron than women 3. Enzymes involved in energy production: Approximately 3% of the iron in the body is found in enzymes that are involved in energy production, such as the enzymes in the electron transport chain.
Four levels of protein structure
1. Primary structure: the sequence of amino acids, linked together by covalent peptide bonds (this ultimately determines its 3D shape) 2. Secondary structure: when the polypeptide folds on itself due to hydrogen bonding, forming alpha helices or beta-pleated sheets 3. Tertiary structure: when the polypeptide folds even more due to interactions among the R groups of the amino acids. 4. Quaternary structure: when multiple polypeptides interact with one another to form a protein with multiple subunits. (not all proteins have one.)
Challenges for vegans
1. Proteins 2. Vitamin B12 3. Calcium 4. Vitamin D 5. Iron
Two dietary forms of vitamin A are
1. Provitamin A carotenoids: found in orange and yellow fruits and veggies as well as veggies with dark green leaves. These carotenoids are converted into vitamin A in the intestinal wall 2. Preformed vitamin A: found in animal foods (liver, eggs, cheese and cod liver oil) and fortified foods (milks, cereals, and margarine)
Two major roles of vitamin A in the body
1. Regulation of gene expression: Vitamin A interacts with proteins in the nucleus that either turn on or turn off gene expression. This has important implications for bone growth, reproduction, embryogenesis, cell differentiation and immunity. 2. Photosensitivity and night vision: Rhodopsin is the light sensitive pigment in the back of the eye, which consists of an opsin protein covalently attached to an organic molecule called retinal. Retinal is a derivative of vitamin A. Vitamin A deficiency can therefore lead to night blindness.
Three categories of fat substitutes
1. carbohydrate-based fat substitutes 2. protein-based fat substitutes 3. fat-based fat substitutes
Lipid functions
1. energy storage 2. essential fatty acids 3. absorption and transport of fat-soluble vitamins 4. insulating and protecting organs 5. cell membranes 6. steroid precursors 7. flavor and satiety
Functions of Protein
1. growth, maintenance and repair 2. Body structure and blood clotting 3. Fluid balance 4. Acid-base balance 5. Immune function 6. Enzymes 7. Hormones 8. Transport 9. Energy
Characteristics of lipids
1. hydrophobic and insoluble in water -dont mix well w water, but do w organic (carbon- containing) solvents such as hexane and petroleum ether. 2. They are associated with flavor. -fats/oils are associated w flavors good and bad. they naturally oxidize when exposed to air which causes the double bonds to form free radicals and compounds that give both good and bad smell and taste. 3. High in calories and good for heat transfer -contain about 9 kcal of energy per gram, compared to 4 kcal per gram in carbohydrates and proteins. Fats are excellent for heat transfer (frying food adds lots of calories) 4. excellent energy storage molecules -both animals and humans store energy in form of fat
Three important chemical differences among fatty acids are:
1. the length of the fatty acid chain 2. the position of the fatty acids 3. the extent to which the fatty acid is saturated with hydrogen bonds, or whether it is unsaturated due to the existence of double bonds.
According to the 2010 Dietary Guidelines for Americans (ages 2 and up) what percent of daily calories should come from fat? What about for infants under 2?
20%-35%; 30-35% which reflects the need for fat in early development.
How many major amino acids are there? How many are essential? What are their names?
20; 9; Threonine, valine, tryptophan, isoleucine, leucine, lysine, phenylalanine, methionine, histidine. TV TILL PM H.
Deficiency/excess of Vitamin C can cause
Deficiency: loss of appetite, tiny red spots on skin, wakens, swollen joints and impaired growth. More severe: anemia and scurvy. Infants can get scorbutic rosary which makes ribs look "beaded". Excess: diarrhea and kidney stones
Collagen
A structural protein forming the connective tissues including bone, teeth, skin and tendons. Vitamin C assists in the synthesis of collagen.
Why do people who follow the Mediterranean diet have a lower risk of becoming obese?
Despite the fact its a high-fat diet that derives 35% of calories from fat, the fats are mainly monounsaturated fats (olive oil) and omega-3 fatty acids from fish.
The three main different kinds of crystals are
Alpha (∂) crystals (the least stable and have the lowest melting pt) Beta (ß) crystals (the most stable and have the highest melting pt) Beta-prime (ß') crystals fall somewhere in-between.
Iron
An important mineral that plays a major role in oxygen transport and energy production in the body. A component of hemoglobin. Stored in the liver, spleen and bone marrow.
Folate deficiencies
As folate is required for DNA replication during cell division, folate deficiency may prevent red blood cells form replicating and lead to macrocytic anemia, a condition in which the red blood cells are immature and fewer in number than normal. Deficiency during pregnancy can lead to neural tube defects in babies like spina bifida, anencephaly (incomplete development of the brain and skull).
Why is obesity associated with fats?
Because there is evidence that people who adopt low-fat diets compensate by adding more carbs and sugars to their diets. It is not the percentage of total fat that matters; its the TYPE of fat that matters.
When does digestion start?
Before the food enters the body. the sight and smell of food triggers the brain to begin secretion of enzymes that will be necessary to digest food.
Fluid recommendations for before/during/after a workout
Before: a person should drink about 7 ml of water or sports drink per pound of body weight (2-3 cups) 2 hrs before working out. During: a person should drink 4-6 cups of liquid per hour. Water for less than an hour workouts, sports drink for anything over to replenish electrolytes. After: should consume 3 cups of liquid (sports drink or water) for every pound lost, and eat salty snacks to replenish electrolytes.
Before/During/After workout for an Athlete
Before: eat carb-rich meal 1-4 hours before work out During: consume easily digestible source of carbohydrate during course of the workout After: eat meal containing both carbs and proteins an hour after workout. should contain about .5 g per pound of carb and either 15-25 g of whey protein or two cups of milk.
Carbohydrate-based fat substitutes
Dextrins, gums, cellulose, and modified food starches are easily digested and give the same mouthfeel as fats. They have fewer kcal per gram but food companies often make up for the difference in taste by using a greater amount of these substitutes which can cause a person to eat just as many calories and possibly more as they would if the product weren't modified
Before/During/After workout for a fitness enthusiast
Before: should eat a carbohydrate-rich meal no more than 4 hrs before working out During: should have a sports drink or other easily digestible source of carbohydrate on hand for workouts lasting more than 45 min After: should eat a meal containing both carbs and protein within an hour after the workout. Working out "primes" the body to build the muscle w protein, so it's important that this meal contain plenty of protein)
the best chocolate have ______, which harden into the firm, shiny, high-quality chocolate. Chefs use a process called ________ to get the cocoa butter in chocolate to harden into this specific crystalline pattern
Beta crystals; tempering
What is the metabolic pathway for fatty acids?
Beta-oxidation of fatty acids produces acetyl-CoA, which can be fed into the citric acid cycle.
BIA
Bioelectrical impedance analysis, involves passing an electric current through the body and measuring the body's impedance (resistance to current). Calculates the amount of fat and lean tissue because lean tissue has higher water content than fat tissue, and thus conducts electricity better than fat tissue.
a Calorie vs a calorie
Calorie (with an uppercase C) is large calorie, and the standard unit of energy, equal to one kcal which is 1,000 small calories. a calorie (with a lowercase c) is a small calorie and a unit of energy in chemistry, specifically the amount of energy required to increase the temp of a gram of water by 1 degree Celsius.
What is the primary source of energy for activity that lasts 20 min or less? for 20 min or more?
Carbohydrates; fat
What are carbs, proteins, and lipids (fats) ultimately broken down into?
Carbs: glucose Protein: amino acids fats: fatty acids each can be used to create energy via cellular respiration
Vitamin A Deficiency Higher Child mortality
Child mortality is higher in vitamin A deficient children
Lipid function: steroid precursors
Cholesterol is a precursor to several steroid hormones, including testosterone, estrogen, aldosterone, and vitamin D.
Why is heart disease associated with fats?
Consumption of fat and high cholesterol is associated w higher risk of heart disease. High LDL (low-density lipoprotein levels lead to the build up of hardened plaque in the blood vessel walls, which can result in atherosclerosis. Atherosclerosis, fatty deposits in the arteries, can lead to a multitude of heart diseases.
What is the metabolic pathway for amino acids?
Deamination of amino acids produces acetyl-CoA, which can be fed into the citric acid cycle.
DEXA
Dual-energy x-ray absorptiometry is a reliable alternative to underwater weighing that measures body fat, bone mineral and muscle using two x-ray energies. Expensive but easy to administer and provides better info about where fat is stored
Who discovered Vitamin A?
E.V. McCollum in 1913, and it was the first vitamin to be discovered.
Vitamin A Deficiency Night Blindness
Eat liver and it will help because liver is an important store of vitamin A. Also called "chicken eyes". Pregnant women w night blindness in the third trimester of pregnancy are more likely to suffer from infection, anemia, and illness, and their child mortality rates are higher as well.
Lipid function: Absorption and transport of fat-soluble vitamins
Fat absorbs and stores the fat-soluble vitamins (vitamins A, D, E, and K) and the body can draw from these stores when it needs to
What is the primary source of energy for low-intensity activity? for high-intensity?
Fat; carbohydrates
Dietary folate vs folic acid
Folic acid is a synthetic form of folate used in enriched foods and dietary supplements. Its absorbed in the small intestine and is more potent than folate, so toxicity is a greater concern. DRIs are based on folic acid rather than folate as a result. the Dietary Folate Equivalent (DFE) is used to convert quantities of folic acid to equivalent amounts of folate.
How do we get our amino acids?
From the food we eat. our bodies break down proteins into their amino acid components and then use amino acids as building blocks to make other proteins. Protein synthesis occurs at the ribosome during the process of translation
Metabolic pathway of glucose (carbohydrates)
Glycolysis breaks glucose into pyruvate even when oxygen is not present. Pyruvate is converted into acetyl CoA, which then enters the Krebs cycle (aka tricarboxylic acid cycle), which produces a large amount of ATP and requires oxygen. When not enough oxygen is present, pyruvate is converted to lactate, which muscle cells can use to produce only a small amount of energy.
HDLs
High-density lipoproteins are primarily made in the liver. Remove excess cholesterol from the blood vessels and cells. Once removed the cholesterol is returned to the liver where its broken down and eliminated. American Heart Association suggests that the optimal HDL to total cholesterol ratio should be 3.5 to 1.
lipid function: Energy storage
Humans store more energy as fat than any other macronutrient which is efficient because fats store more energy per gram than any other macronutrient
Visible fats
butter, margarine, lard, olive oil and marbling in meat
Vitamin A is stored?
In the liver. These stores provide a critical supply of vitamin A during periods when a person does not eat enough of it in the diet
Why should an athlete consume a highly digestible carb source during workout?
It delivers sugars to the bloodstream and thus the muscle tissues which allows athletes to workout faster, longer and harder and have more stamina. Consuming a sports drink during a workout spares the liver from having to break down glycogen, and it delivers glucose to the tissues more quickly.
What is the purpose of protein? What elements does it contain?
It plays major roles in tissue development, maintenance and repair, as well as fluid balance, enzyme production, hormone regulation and blood clotting; carbon, hydrogen, oxygen and nitrogen.
Function of protein: Energy
Least efficient use of protein, only used when carbohydrate intake is too low, though protein is not the most efficient or desirable source of energy. The body doesn't store excess protein so if protein has to be broken down 4 energy it has to come from the muscle.
What percent of daily calories should come from saturated fat? trans fat?
Less than 10%; as little as possible.
Basic structure of lipids
Lipids has no single common structure. The most commonly occurring lipids are triglycerides and phospholipids. they are a glycerol molecule which looks like a capital E, with 3 fatty acids one attached to each bar of the E
Vitamin A Deficiency Higher Infant mortality
Many scientists believe that administering a single dose of vitamin A to newborns will reduce the risk of infant mortality
Digestion and absorption of Alcohol
Most alcohol is absorbed into the bloodstream, and they don't require food to be transported in the blood. It then goes to the liver to be detoxified
Fat-based substitutes
Nondigestible lipids can be used to make these substitutes like Olean (Olestra), Salatrim, and Caprenin. These foods contain less calories and aren't thoroughly digested so they end up being less caloric. but they can cause cramping and inhibition of the absorption of fat-soluble vitamins and other nutrients. as a result FDA requires foods containing Olestra to be fortified with fat-soluble vitamins and requires a label w a warning of the neg health affects associated w olestra.
Negative nitrogen balance
Occurs during starvation, low calorie diets, or illness, when nitrogen intake is less than nitrogen excretion.
Calcium and blood pressure
People recognized that a high calcium diet reduced the risk that pregnant women would develop preeclampsia, a serious disorder characterized by high blood pressure, fatigue, headache and protein in the urine. also can reduce blood pressure in ppl w hypertension
Digestion and absorption of Protein
Pepsinogen in the stomach combines with hydrochloric acid to form the activated enzyme pepsin. Pepsin begins protein breakdown to smaller peptides and the stomach acid denatures the proteins. In small intestine, pancreatic enzymes further break down the smaller peptides into individual amino acids, which cross the epithelial lining in the bloodstream. The amino acids pass to the liver and are then used either to make proteins, to add to the amino acid pool, or to make energy (depending on the body's needs).
Lipid function: cell membranes
Phospholipids are important components of cell membranes which selectively allow certain compounds to enter and exit the cell. Cholesterol is another cell membrane component; it maintains cell integrity and fluidity.
---Cobalamin (vitamin B12) and its functions
Plays a role in bone metabolism, amino acid metabolism, and DNA synthesis. it is involved in the conversion of folate to a form that the body can use, so vitamin B12 deficiency often causes folate deficiency. Also maintains the Myelin Sheaths that insulate nerve fibers, enhancing conduction of electrical signals in the nervous system.
Why is iron a challenge for vegans?
Present in many plant-based foods like all dark-green veggies. Not as readily absorbed as iron in meat. Fiber in veggies can also block iron absorption. Its a good idea to mix iron-containing veggies w vitamin C containing foods to help w iron absorption.
What does the liver do to assist in digestion?
Produces bile, which assists in the digestion of FAT in the small intestine. It is produced in the liver and stored in the gallbladder.
PCDAAS
Protein Digestibility-Corrected Amino Acid Score, which ranks foods from 0-100 based on protein quality. establishes the %DV for protein on food labels.
PEM
Protein energy malnutrition, when a person consumes an inadequate amount of protein and energy. PEM is the most severe form of malnutrition worldwide.
Metabolic pathway of amino acids
Proteins are the body's least-preferred energy source, but they're sometimes used for energy when supplies of carbohydrates are limited. The nitrogen group must be removed from the amino acid in a process called deamination, leaving a carbon skeleton that can enter the Krebs cycle in a number of different places.
REE
Resting Energy Expenditure: the amount of energy required every day during resting conditions, 2/3 of a persons daily caloric needs. Depends on many factors- height, gender, muscle mass, physical environment, health status, meal patterns and caffeine/nicotine intake among others. People with greater muscle mass tend to have higher resting energy expenditures
Children have ______ which is an enzyme that breaks down fats.
Salivary lipase
Digestion and absorption of Fats
Salivary lipase breaks down fats but it is not activated until it reaches the stomach. Most fat breakdown and absorption happens in the small intestine. Bile from the gallbladder must emulsify fats in the small intestine and prepare them for digestion by pancreatic lipase, which breaks fats into glycerol and fatty acids, which are absorbed into small intestine. They then re-assemble into triglycerides, which join with cholesterol, proteins, and phospholipids to form special carriers called chylomicrons that allow fat to enter the lymphatic system and ultimately the blood.
Function of protein: Transport
Some proteins (albumin) assist in the transport of substances in the body.
---Pyridoxine sources in food and its deficiencies/excessive
Sources: beef liver, meat, poultry, salmon, bananas, watermelon, spinach, broccoli, potatoes and navy beans. Deficiency: depression, dermatitis, anemia, convulsions, vomiting and reduced immune response. Excessive: depression, fatigue, headache, nerve damage that may be irreversible.
---Fat-soluble vitamins
Stored in the liver and in fat cells, and they remain in the body longer than water-soluble vitamins. Vitamin A, Vitamin D, Vitamin E, Vitamin K. Don't need to be consumed everyday, deficiency occurs relatively slowly and toxicity is a concern
What is the metabolic pathway for glucose?
The breakdown of glucose begins in the cytosol, where glucose is converted to pyruvate in the process of glycolysis. it doesn't require oxygen, and it produces a small amount of ATP. Pyruvate then enters the mitochondrion where tis broken down to acetyl-CoA, which produces a small amount of ATP through substrate level phosphorylation. The majority of ATP production occurs in the electron transport chain, which exists along the inner mitochondrial membrane
VLDLs
Very low-density lipoproteins, made in the liver and contain cholesterol and triglycerides, they deliver triglycerides to tissues.
---The B vitamins
Thiamin (vitamin B1), Riboflavin (B2), Niacin (B3), Pyridoxine (B6), Folate (B9), Cobalamin (B12), Biotin (B7), Pantothenic Acid (B5), a group involved in energy metabolism. They don't provide energy directly but they act as coenzymes (which increase enzyme activity) or cofactors (required for enzymes to work) that help extract energy from foods.
Leucine trigger
Tons of leucine consumed will trigger the body to start muscle protein synthesis and form new muscle. Whey protein will trigger this which is why athletes should consume this after a workout.
Lipid oxidation
Unsaturated fats have a greater potential for oxidation than saturated fats. Specifically, oxidation occurs at the site of the double bonds of an unsaturated fat. Lipid oxidation ruins the taste, smell, and general quality of food, and its generally unsafe to consume oxidized lipid
---Phosphorous
Usually found in phosphate molecules. Most of the body's phosphorous is found in the bones, but some is in soft tissues. Functions: a structural component of DNA, RNA, and phospholipids (including those in cell membranes and lipoproteins). Acts as a pH buffer in the blood and is an important component of ATP. Food sources: abundant i the food supply. meat, poultry, fish, milk, eggs, cereals, grains, legumes, and colas.
---Thiamin
Vitamin (B1) Function: plays role in energy production and in proper functioning of nerve and muscle cells. Good food sources: pork, peanuts, organ meats, whole grains, enriched grains/pasta, orange juice and milk. Deficiencies: causes beriberi, a disease in which the heart enlarges, fluid accumulates under the skin and muscles become weak. Wet beriberi (affects the cardiovascular system), dry beriberi (wet affects the nervous system). Severe: in alcoholics causes Wernicke-Korsakoff syndrome, a neurological disorder that involves loss of short-term memory, disorientation and jerky eye movement
Vitamin A Deficiency Impaired immunity
Vitamin A deficient children are more likely to die from measles, dysentery, and many other infectious illnesses. May be because vitamin A enhances the response of cell-mediated and humoral immunity, or because vitamin A is critical to proper epithelial cell differentiation
---Cobalamin and sources in food
Vitamin B12, contains cobalt and is found naturally only in foods from animals and is synthesized by microorganisms. Sources: milk, cheese, meat, poultry, seafood, some fortified breakfast cereals.
---Riboflavin
Vitamin B2 Function: its a component of two important coenzymes (NAD AND NADP), and its involved in releasing energy in food. Good sources: milk, enriched cereals, breads and pasta. Its stable at high temps but UV destroys it. Deficiency: causes skin rashes, sore throat, cracks in corner of the mouth, and hypersensitivity to light. Excessive consumption will turn pee bright yellow
---Niacin
Vitamin B3, a component of two important coenzymes (NAD and NADP), its involved in releasing energy from food and in the building of fatty acids. Good sources: meat, eggs, poultry, fish, nuts, and whole grain and enriched cereals. Deficiency: can cause pellagra, a disease that causes dermatitis, diarrhea, dementia, and death (4 D's) most ppl don't develop symptoms because the body can synthesize niacin from tryptophan. Toxicity symptoms: "nitrogen flush", the face, arms and chest become red due to capillarydilation. cause stomach ulcers, vision loss, and liver injury
---Pantothenic acid
Vitamin B5, involved in the synthesis of lipids, hemoglobin, steroid hormones, neurotransmitters, and is part of a larger molecule that is used to harness energy. Ubiquitous in foods, though food processing destroys it, deficiency is rare.
---Pyridoxine and its functions
Vitamin B6: most common and active of 7 forms of vitamin B6. Function: role in many biochem reactions like reactions that convert amino acids from one form to another, the reaction that converts tryptophan to niacin, and reactions that synthesize glucose, some lipids, serotonin, and hemoglobin. Plays role in immunity, glycogen breakdown, and brain development
---Biotin
Vitamin B7, which plays a role in the breakdown and synthesis of fatty acids, breakdown of amino acids, the production of glucose, and gene expression. Bitten is ubiquitous in foods and deficiency is rare
---Folate and its functions and sources in food
Vitamin B9. Functions: plays an important role in tissue maintenance and cell division. It's required for DNA replication. Sources: orange juice, green leafy veggies, beans, sprouts, and organ meats, many fortified breakfast cereals. Folate is heat sensitive so cooking foods often significantly reduce the amount of folate they deliver. Consume 600 micrograms of folate daily.
---Water-soluble vitamins
Vitamin C, the B vitamins [Thiamin (vitamin B1), Riboflavin (B2), Niacin (B3), Pyridoxine (B6), Folate (B9), Cobalamin (B12), Biotin (B7), Pantothenic Acid (B5)]. These quickly excreted in the urine. because they're not stored in the body, concerns about toxicity aren't as high as with fat-soluble vitamins. A person can usually take a relatively large dose of a water-soluble vitamin without experiencing the effects of toxicity.
Anaerobic metabolism
When cellular oxygen levels are low, anaerobic metabolism produces a small amount of ATP in the absence of oxygen.
Deamination
When the body removes the amino group from free amino acids, forming ammonia and keto-acid. Leto-Acid can be used to make fatty acids or for energy production, and ammonia is converted to urea and then excreted from the body.
Why is whey protein/milk important after a workout for athletes?
Whey protein is a component of milk and its important 4 athletes because its rich in leucine, an amino acid. Leucine triggers the synthesis of muscle protein. If lots of whey protein is consumed after workout it will trigger the formation of muscle. Whey protein also has additional amino acids that are required to build the new muscle.
Calcium and bone health
With the help of vitamin C, collagen forms the "framework" for bone, and calcium forms the crystal deposits called hydroxyapatite that strengthen the bone.
Helicobacter pylori
a bacterium that destroys the stomach's protective mucus lining. It's transmitted in contaminated food or water or through human contact, what 90% of stomach ulcers are caused by.
Iron Deficiency and its consequences
a general term for a lack of iron stores in body, can cause anemia or hemoglobin deficiency; reduced immune function and exercise capacity, poor cognitive performance, growth retardation, and poor pregnancy outcomes.
---Vitamin E
a group of compounds called tocopherols. Its an antioxidant that fights against free radicals. They neutralize these free radicals by donating an unpaired electron (also used as a food preservative because it prevents oxidation that would otherwise lead to to rancidity). Also plays a role in nerve cell development and the immune system. Good sources are veggie oils, margarine, salad dressing, nuts, seeds, wheat germ, and green leafy veggies.
eicosanoids
a group of metabolically active chemicals with important physiological effects such as promoting blood clotting and relaxing blood vessels, come from EPA and DHA.
---Calcium
a macromineral that accounts for 1.5% of total body weight and 40% of the mineral content of the body. It's by far the most abundant mineral in the body. It plays important roles in bone health, muscle and nerve function, metabolism, blood clotting and pressure. Good sources: milk, canned salmon, sardines, green leafy veggies and broccoli. Calcium citrate and calcium carbonate supplements are also available
Transit time
a measure of the time it takes food to travel the entire length of the digestive tract. Ranges 12-40 hours
---Zinc
a micromineral, a cofactor that plays a role in the function of hundreds of enzymes and metabolic pathways. Functions: alcohol metabolism, protein digestion, DNA replication, gene regulation, immune function, antioxidant enzyme function, blood pressure regulation, protein synthesis, bone growth development of sexual functions, insulin function and wound healing.
Emulsion
a mixture of two liquids that are normally not miscible, such as water and oil. Named based on the primary component of the combined mix; oil-in-water emulsions have more water than oil and vice versa.
Triglycerides
a molecule that consists of three fatty acids attached to a glycerol backbone via ester linkages (a three carbon glycerol and three fatty acid tails). They are the main constituents of fat in plants and animals
---Beta-carotene
a pro-vitamin molecule (molecules that have to be converted into their active vitamin form) which is converted into vitamin A. Measured in retinol activity equivalents (RAEs)
Transamination
a process in which the nitrogen-containing amine group from one molecule is transferred to another. this is what produces amino acids.
Hydrogenation
a process where unsaturated fats are converted to saturated fatty acids. It essentially removes some or all of the double bonds, potentially converting the fat from a liquid to a solid at room temp
Hemoglobin
a protein that has a quaternary structure. Has 4 subunits that interact with one another to form the final, functional protein. Carries oxygen in red blood cells.
albumin
a protein that transports drugs, hormones, and fatty acids.
Appetite
a psychological mechanism that determines how much we eat.
Enterocyte
a single cell each microvillus has
Brush border
a thin membrane lining the small intestine collectively formed by the microvilli
Chemical energy
a type of potential energy stored in the bonds of carbohydrates, fats and proteins. Eating food supplies the body w chemical energy.
Cholesterol
a type of sterol (a group of lipids) that occur naturally in animals, found in animal cell membranes. Responsible for membrane fluidity and for keeping cell membranes intact, and it makes up approximately 30% of the cell membranes in animals
---Function of Vitamin C
acts as an antioxidant in the watery portion of the cells and it plays an important role in the immune function. Also assists in the synthesis of COLLAGEN, a structural protein forming the connective tissues including bone, teeth, skin and tendons. Also helps to maintain blood vessels and heal wounds.
Capillary network
brings blood to the villus and takes blood away from it, inside each villus. Glucose and amino acids are directly absorbed into the bloodstream via these.
Metabolic pathway of Triglycerides (fats)
after they're broken down into their components glycerol and fatty acids, Glycerol is broken down to pyruvate or glucose in the liver and the fatty acids are broken into acetyl-CoA in a process called beta oxidation. Acetyl CoA joins with oxaloacetate (OAA) to begin the Krebs cycke, but OaAA is only available when carbohydrate intake is high. For this reason, carbohydrates are necessary to burn fat.
Accessory organs
aid in digestion but aren't part of the digestive tract. Salivary glands, liver, pancreas, and gallbladder.
Complete protein
aka a high-quality protein delivers all of the essential amino acids in the amounts needed by the body and is easy to digest and absorb. Animal products are common sources. Soy products (tofu, soy dairy), are also sources that have no cholesterol, little saturated fat, and other desirable components (vitamins minerals, isoflavones, and plant estrogens).
Semivegetarians
aka flexitarians generally practice a vegetarian diet but occasionally eat meat/seafood
Energy metabolism
all the biochemical reactions in cells that turn this chemical energy into usable energy in the form of ATP. Most energy producing metabolic pathways occur in the mitochondria.
---Vitamin D
also called cholecalciferol is derived from cholesterol and is simultaneously a vitamin and a steroid hormone. Can get it from the sun, milk, cereal, fortified juices, oily fish and fortified liver, salmon, sardines and shrimp.
Proteins are made up of monomers called
amino acids
Basic structure of amino acids
an alpha carbon bonded to an amino group, a carboxyl group and a variable "R" group. The "R" group is what makes one amino acid different from the others and its what gives it its distinctive chemical properties such as polar or non polar.
Interesterification
an enzymatic reaction that rearranges the fatty acids on the glycerol backbone of a triglyceride, which gives the triglyceride different physical properties, such as a higher melting pt.
CLA (Conjugated linoleic acid)
an omega-7 fatty acid found in dairy products and dietary supplements
Vitamin A Deficiency Keratomalacia
another eye disorder, it is the leading cause of preventable blindness in the world and it particularly impacts young children. When Vitamin A intake is too low the tissues in the eye undergo keratinizing metaplasia and produce dry dead white patches of cells called Bitot's spots which can be wiped off the eye if they're concentrated in the sclera but they can cause permanent blindness if they migrate to the cornea and cause corneal necrosis
the end products of lipid oxidation
are "secondary products" such as aldehydes, ketones, alcohols, and carboxylic acids. These often produce foul odors and tastes.
Too much cholesterol can lead to
atherosclerosis, heart attacks, and strokes.
Lacto-vegetarians
avoid eggs, seafood and meat but still consume milk and dairy.
Digestion and absorption of carbohydrates
begins with salivary amylase, breaks down complex carbs in the mouth. Enzymes that break down carbs in the small intestine include pancreatic amylase, lactase, sucrase, and maltase. Eventually they're broken down into monosaccharides (simple sugars including glucose, galactose and fructose), which can pass through the lining of the small intestine and into the bloodstream. Ultimately all monosaccharides are converted to glucose, which is the major monosaccharide that circulates in the blood. Glucose is ultimately used by cells to make ATP.
Function of protein: Fluid balance
blood proteins ensure the proper balance of fluids inside and outside the vessels. More than half of the protein in human blood is albumin.
Extremely rapid weight loss accelerates the loss of _____ and ______ instead of ______.
body water; muscle; fat. Lost muscle mass is more likely to be replaces with fat than with new muscle mass.
Denaturalization of proteins
can happen if they're exposed to extreme changes in temp, acidity or other conditions. This causes the protein to retain its primary structure but lose its higher-level structures and therefore lose its function. It may or may not be able to regain those structures if the extreme conditions are removed.
Atherosclerosis
can lead to high blood pressure and ischemia which can damage tissue, and also lead to arteriosclerosis, heart attacks, and strokes. Atherosclerosis can lead to angina proctors which can ultimately lead to a myocardial infarction or stroke. Plaque buildup in the arteries can lead to thrombosis which can dislodge and cause further health issues.
Invisible fats
can't be seen in food, but still there. Ritz crackers, many fatty meats.
Carbohydrate/Protein/Fat Needs for Fitness enthusiast
carb: 5-7 g/kg protein: .8-1 g/kg fat: remaining kcal needs
Fatty acids
carbon chains with two ends, one one end is the methyl group (-CHv3) (hydrophobic) and on the other end is the carboxyl group (-COOH) (hydrophilic). the shorter the chain the less hydrophobic
Both fats and carbohydrates contain the same elements __________________ , but fats have twice as many ______ as carbohydrates which is why fats provide twice as much ______ per gram as carbohydrates
carbon, hydrogen, and oxygen; hydrogen atoms; energy
Where do carbs, proteins and lipids (fats) end up after digestion?
carbs and proteins travel to cells in the blood. lipids are first absorbed by the lymphatic system and eventually incorporated into the blood when they reach the liver. All of these nutrients ultimately end up in cells, where cellular respiration occurs.
Carb/Protein/Fat needs for athletes
carbs: 6-12 g/kg protein: 1.2-1.7 g per kg Fat: remaining kcal needs
Phospholipid
category of lipids. Major role is to form cell membranes and lipoproteins. Contains a three-carbon glycerol backbone bonded to two fatty acid tails and a phosphate group. This results in an amphipathic molecule with a hydrophilic phosphate end and a hydrophobic methyl end. Body can synthesize easily. commonly used as emulsifying agents, which allow fat to mix w water.
Why is consumption of oxidized fats a health concern associated with lipids
causes inflammation, brain damage, and increase the risk of diabetes and cardiovascular disease.
Exposure to enzymes can cause lipid oxidation bc
certain enzymes like lipoxygenase (found in high concentration in soy beans) can initiate oxidation.
Pyloric sphincter
chyme moved from the stomach through this pyloric sphincter into the small intestine. Plays an important role in regulating the length of time that food remains in the stomach.
Central lacteal
continuous with the lymphatic system and absorbs FATS into the lymphatic system, inside each villus.
Gastroesophageal sphincter
controls the movement of food between the esophagus and the stomach. IT ensures food and stomach acid doesn't move back into esophagus. When it doesn't work properly ppl will experience heartburn which is common in fat ppl and pregnant women.
Cobalamin (Vitamin B12) deficiency
deficiency due to lack of intrinsic factor (a protein the stomach secretes to protect B12 from degradation), may result in pernicious anemia, in which red blood cells are megaloblasts (immature, enlarged, and fewer in number than normal). Can result in nerve damage and death, so patients lacking intrinsic factor are often given vitamin B12 injections. Vegans, older ppl and women who're pregnant/lactating should be mindful of B12 needs.
lipid function: Essential fatty acids
dietary fat includes the essential fatty acids linoleic and linolenic acids. Linolenic acid can be converted to EPA and DHA, which are in turn converted to eicosanoids, a group of metabolically active chemicals with important physiological effects such as promoting blood clotting and relaxing blood vessels
Sickle-cell anemia
disease in which a single incorrect amino acid is incorporated into the sequence that codes for hemoglobin, which causes the red blood cell to be sickle-shaped which further prevents the complete bonding of hemoglobin and oxygen together and causes the red blood cells to clump together. Symptoms: fatigue, shortness of breath, pain, ultimately permanent damage to kidneys, lungs, eyes and central nervous system.
Definition of Lipids
diverse group of molecules that include waxes, pigments, terpenes, sterols (like cholesterol), phospholipids, and triglycerides.
Two important omega-3 fatty acids are
docosahexaenoic acid (DHA) and eicosapentaeonic acid (EPA) (found in cold water fish)
Lacto-ovo vegetarians
dont eat meat or seafood but consume eggs and dairy
Macrobiotic vegetarians
dont eat meat, poultry, eggs or dairy. Primarily eat whole grams, veggies, frost, soy, nuts and occasionally whitefish.
Which has a lower melting point/more likely to be liquid at room temperature, fatty acids with double bonds or no double bonds?
double bonds because fatty acids with no double bonds are better able to "pack in" with one another.
Methylene-interrupted double bonds
double bonds in a Methylene-interrupted double bond system are separated by two or more methylene groups. these are most common in most fatty acids
Zinc deficiencies
dwarfism, deformed bones, poor would healing, problems with sexual development, reduced ability to taste food, hair loss, defects of the central nervous system, inability to properly absorb and transport vitamin A and folate, and a number of other developmental problems.
Fats contain a lot of _______ compared with other macronutrients
energy. it contains twice as much energy per gram as protein or carbs (fat: 9kcal/gram, protein: 4kcal/gram, carbs: 4kcal/gram)
Enriched foods
enrichment involves the restoration of nutrients that were originally in a food but were lost during processing.
Exposure to catalytic metals can cause lipid oxidation bc
even small amount of iron, copper, etc can serve as a catalyst for autooxidation. These metals can come from impurities in the plant material or contamination of the packaging or processing equipment. Normally "ground-state oxygen" can't react w double bonds because of the spin states of the valence electrons are different. Metals and other catalysts initiate the reaction by removing an electron from either the oxygen or the lipid or by changing the spin of the electrons in the oxygen molecule. This allows free radical oxidation to begin.
Lipid function: flavor and satiety
fat adds desirable flavor and texture to food and it contributes to satiety- the feeling of fullness after eating. A low-fat meal won't keep you full after long which is why experts don't recommend eating extremely low-fat meals even during a diet.
Lipid function: insulating and protecting organs
fat insulates the body from the environment, and it surrounds and protects the vital organs.
Adipocytes
fat storing cells. Part of the reason why people have trouble losing weight is that weight loss reduces the size of adipocytes but it does not reduce their number. As a result people may find it easier to store excess calories in already existing adipocytes when they go back to over eating.
Categories of fats (lipids) include
fatty acids, triglycerides, phospholipids, and sterols (cholesterol)
Villi
finger like projections in the small intestine that increase the surface area for absorption of the important macronutrients. Each is connected both to the bloodstream and to the lymphatic system.
Initiation of lipid oxidation
first step of lipid oxidation, when a catalyst produces a fatty acid radical.
Ileocecal Valve
food moves from the small intestine through this valve to the large intestine, which reabsorbs water and some vitamins and minerals.
Incomplete protein
food that doesn't contain all of the essential amino acids in the amounts needed by the body. Ex: veggies and grains. Need to eat complementary proteins to get all of the amino acids they need
Complementary proteins
food whose combined amino acid content provides all of the essential amino acids. EX: rice and beans. Vegetarians need to pay attention to these.
Problem associated with partial hydrogenation is the
formation of trans-fats, which are associated w heath problems such as high cholesterol. some of the fatty acids are converted from cis- to trans- before the removal of double bonds.
Fortified foods
fortification involves the addition of vitamins and minerals that were not in the food item in the first place. Calcium is often added to orange juice and folic acid is often added to breakfast cereals.
Why is Vitamin D a challenge for vegans?
found generally in fatty fish, egg yolks, and liver. Need to either get a lot of sun or eat products fortified w Vitamin D (soy milk or OJ). Don't take supplements bc of concerns about toxicity.
there are no naturally occurring ______ oils. The closest thing is ________
fully saturated oils; palm kernel oil which consists of about 80% saturated fat
Microvilli
further hairlike projections on villi that increases the surface area even more to capture the nutrients in the small intestines.
Exposure to heat can cause lipid oxidation bc
general rule of thumb in chem is that reaction rates double for every 10degrees celsius increase in temp. same goes for lipid oxidation at higher temps
Monounsaturated fatty acid
has a single double bond, oleic acid is an example
Unsaturated fatty acid
has one or more double bonds, so it doesn't contain the max # of hydrogen atoms. usually liquid at room temperature, shown to lower blood cholesterol
Obesity and its causes
have a higher risk of hypertension, high blood cholesterol, type 2 diabetes, coronary heart disease, stroke, congestive heart failure, certain kinds of cancer, kidney disease, liver disease, restricted mobility, poor reproductive health and back problems, and a heightened risk of premature death in general. largely due to larger portion sizes and food choices that are high in fat, sugar and calories. People are eating out more than ever and research shows that people tend to eat larger quantities of food that is bad for them when they eat out. Fast food places also suck.
Under weight people and their health problems
have a weakened immune system, heart problems, delayed wound healing and infertility. Can cause osteoporosis, where bone mass and bone density decrease as the bones become more porous and brittle.
cis isomers (cis-fatty acids)
have hydrogen bonds on the same side of the double bond. "kinkier" and thus less likely to be straight than trans-forms.
Saturated fatty acids
have no double bonds- their carbon atoms are saturated with hydrogen bonds. Steric acid (18:0), which means there is a total of 18 carbon molecules and no double bonds
Polyunsaturated fatty acids
have two or more double bonds and are even "kinkier" than the oleic acid molecule. Linoleic acid (18:2w6) (an essential fatty acid) is an example, melting pt is 23 degrees because it has more double bonds
Recommendations for protein intake
healthy adults should consume .8 grams of high quality protein per kilogram of body weight daily. This is higher for athletes, pregnant women and people who or ill/recovering from an injury.
Leptin
hormone produced by fat tissue that acts as a satiety signal, telling the brain that body fat has increased and that the body fat has increased and that the body has had enough to eat which triggers a decrease in appetite and brings body fat down to desired levels.
Vitamin A Deficiency Impaired Growth
in 1913, McCollum performed experiments showing the growth of malnourished rats dramatically improved when they were provided a small amount of fat containing vitamin A.
Most of the cholestoral we need is produced
in the liver, and this cholesterol is recycled so we dont have to consume much of it in the diet.
Exposure to visible light can cause lipid oxidation bc
it just can. for ex: high-end, extra-virgin olive oil contains chlorophyll which will initiate the oxidation process if exposed to light. this is why olive oil is generally dark brown or green (to keep visible light out)
Two main essential fatty acids in the diet are
linoleic acid (18:2w6) and linolenic acid (18:3w3). Humans are able to enzymatically change omega-3 and omega-6 fatty acids to other forms but mammals can't convert between omega-6 and omega-3 fatty acids. This is why they must be consumed in the diet.
Cholesterol is transported in the blood via ______ which are ________. The 4 types are ________
lipoproteins; spherical structures containing a phospohlipid bilayer that serves as a "shell" surrounding the hydrophobic cholesterol molecules so that they can be transported in the blood; Chylomicrons, Very-low density lipoproteins (VLDLs), Low-density lipoproteins (LDLs), High-density lipoproteins (HDL).
Fasting, skipping meals, and eating very low-cal diet (under 1,200 cals) does what?
lowers ones metabolism.
Saturated fatty acid
maximum possible # of hydrogen atoms because it contains no double bonds.. Usually solid at room temperature, thought to increase blood cholesterol levels.
Kwashiorkor
means "the sickness of the weaning" in Ghana. Condition in which children have a swollen abdomen. occurs most often in kids who transition from breast milk to high-starch, low protein cereal. they get enough calories but not enough protein. Changes in gastric bacterial populations is also a factor.
Why is protein a challenge for vegans?
meat proteins are typically higher-quality proteins than plant proteins. Only soy is comparable. Legumes, seeds, nuts, grains and veggies contain some.
---Good sources of zinc
meats, eggs, poultry, whole-grain cereals, oysters herring and legumes. Refined grains and fruits are poor sources of zinc. Zinc absorption in the small intestine is promoted by the presence of meat, poultry, and fish in the diet.
Stomach
mixes and churns food and secrets HYDROCHLORIC ACID, PEPSIN (which breaks down protein), and GASTRIC LIPASE (which breaks down fats) to further digest the food.
Major organs of the digestive system are
mouth, pharynx, esophagus, stomach, small intestine, large intestine and anus. All are directly involved with digestion and they're part of the digestive tract.
Positive nitrogen balance
occurs during pregnancy, growth, and recovery from illness, when nitrogen intake exceeds nitrogen excretion.
Polypeptide synthesis
occurs through a series of dehydration reactions
Common unsaturated fatty acids found in foods are
oleic acid (18:1w9), linoleic acid (18:2w6), Linolenic acid (18:3w3) and arachidonic acid (20:4w6).
18:1w9 fatty acid (pronounced 18-1-omega-9) is the scientific name for.... The numbers mean...
oleic acid; 18 means there are 18 total carbons in the fatty acid chain, 1 means there is one double bond in the carbon chain, 9 means that the first double bond (in this case the only double bond) occurs at the w9 position (9 carbons in from the omega end of the molecule)
Veggie/soybean oil has a high level of ____-
omega-6 fatty acids
Limiting amino acid
one that is not present in adequate amounts through dietary protein. When this happens protein synthesis will either not occur or the body will break down existing protein to obtain it.
Why is vitamin b12 a challenge for vegans?
only found in animal foods, so they have to take either supplements or eat foods that are fortified with B12. Best absorbed on an empty stomach.
---Sources of Vitamin A
orange and red fruits and veggies; carrots, squash, sweet potatoes, pumpkins, spinach, broccoli, dark green leafy veggies; liver, eggs, fortified milk, cream, butter, cheese, margarine.
Omega-3 fatty acids
particularly important structural components of the brain and retina. Primary sources are fish, seaweed, and algae, also found in flaxseed, chia, and kiwifruit seeds.
Vitamin A deficiency
particularly problematic in the low-income world where a lack of adequate food supplies makes protein energy malnutrition and micronutrient deficiencies common. Particularly true for infants, children and mothers who often suffer significant health consequences after years of malnutrition, which often leads to chronic diseases, disabilities and mortality.
Plants produce a different class of sterols called
phyosterols
A fatty acids chemical structure determines its...
physical properties (and the physical properties of the triglycerides and fats it compromises).
Food sources of lipids
plant based oils, nuts, avocado, salmon, tuna, herring, egg yolk
Android body fat
ppl w this body fat distribution pattern store most of their body fat in the abdomen (apple shaped). Specifically, fat can be stored as visceral fat (under the ab muscles) or as subcutaneous fat (under the skin and over muscle)
Why is calcium a challenge for vegans?
present in veggies (broccoli&kale), but its not readily absorbed by body. Need to take supplements or eat foods fortified w calcium
The small intestine
primary site of absorption of nutrients into the blood or lymph (20 ft long and convoluted). Divided into three parts: duodenum (where food enter), jejunum (where most absorption happens), and ileum (interfaces w the large intestine). Accessory organs secrete substances into duodenum to assist in digestion.
Salivary amylase
produced by salivary glands which begins the process pf chemical digestion of carbs in the mouth.
What does the pancreas do to assist in digestion?
produces several digestive enzymes secreted in small intestine: pancreatic amylase (breaks down carbohydrates), pancreatic lipase (breaks down fats), and trypsin/chymotrypsin (breaks down proteins). Also releases bicarbonate, which neutralizes the highly acidic contents that enter the small intestine from the stomach.
Function of protein: Body structure and blood clotting
protein is the major component of muscle and its found in connective tissue such as tendons and ligaments. Most abundant protein in the body is collagen, found in all connective tissue. Also involved in blood clotting and it forms hair and malls.
Function of protein: acid-base balance
proteins act as buffers that play a role in acid-base balance, in which the body strives to keep fluids toward neutral pH so that the body can function normally.
Function of protein: growth, maintenance and repair
proteins are continuously being broken down and rebuilt and its important to continuously replace the essential amino acids by eating protein.
Function of protein: Immune function
proteins called antibodies defend agains antigens in the immune system. The body produces mucus (contains amino acids) to trap foreign substances from invading the body in the first place.
Large intestine
reabsorbs water and some vitamins and minerals. broken into 3 parts: ascending, transverse and descending portions. Think of it as the "drying and storing" organ for feces because it reabsorbs water and stores feces until a bowel movement.
Full hydrogenation
removes all of the double bonds in an unsaturated fatty acid, which produces an extremely hard fat. therefore they contain no trans-fats/
Why is consumption of medium-chain fatty acids a health concern associated with lipids
research suggests that medium-chain fatty acids (6-12 carbons in length) may have health benefits. These medium-chain triglycerides include caprice, caprylic, capric, and lauric acids, which can be found in tropical oils.
Why is consumption of saturated fats a health concern associated with lipids
scientists recommend that people limit intake of saturated fat and consume unsaturated fats instead. Omega-9 (such as oleic acid) and omega-7 monounsaturated fats are thought to have heath benefits. Polyunsaturated fats (omega-3 and omega-6 fats) are important because they can be enzymatically converted to other useful polyunsaturated fats via elongation and desaturation.
Propagation of lipid oxidation
second step of lipid oxidation, the fatty acid radical reacts with molecular oxygen, producing a peroxyl-fatty acid radical which is unstable and reacts with another free fatty acid radical, producing a lipid peroxide and a different fatty acid radical which can continue the reaction in the same way.
The most effective weight loss plans involve
small, gradual lifestyle changes that can be maintained over the long run. Typically involves increasing physical activity and reducing portion sizes.
Function of protein: Hormones
some proteins (like insulin) act as hormones, signaling molecules that travel in the blood to have an impact on specific cells or tissues.
Function of protein: Enzymes
some proteins are enzymes which speed up chemical reactions without being consumed in those reactions. They're able to carry out specific chemical reactions because of their characteristic shapes. When a problem in the genetic code prevents a person from producing an enzyme an inborn error in metabolism occurs (lactose intolerance: ppl can't produce the enzymes needed for lactose breakdown)
What can too much protein do to the body?
strain the kidneys and disturb the body's fluid balance.
BMI
the Body mass index is a number based on a person's height and weight. This can be used to determine whether a person is underweight, overweight or obese. formula: weight in kg/height in meters. Under 18.5 is underweight and 25 and over is overweight and 30 is obese. Not a perfect scale because it doesn't distinguish between muscle mass and fat.
Basal Metabolic rate/ Basal metabolism
the REE measured after waking up in the morning and at least 12 hours after a meal. Basal metabolism is the metabolism involved in involuntary bodily processes, such as heartbeat and breathing. A person with slower basal metabolism requires fewer calories and may have a more difficult time losing weight.
Protein turnover
the balance of protein synthesis and protein breakdown, critical to meet the body's ever-changing demands
Glycogen
the body can store glucose in the form of glycogen in the liver and muscles, which can then be broken down into glucose whenever the body needs it. Glycogen stores are usually depleted quickly. During a workout (when body needs more glucose), it breaks blood glycogen down into its glucose monomers. When blood glucose runs low the body breaks down stored glycogen in the liver and glucose is released into the bloodstream.
Steric acid (18:0)
which means their is a total of 18 carbon molecules and no double bonds. there are no "kinks" in this fatty acid chain because there are no double bonds. this means that stearic acid can pack in more closely with other saturated fatty acids, which means it has a higher melting point than oleic acid (158 degrees vs 60.8). This is why stearic acid is solid at room temp and oleic acid is liquid