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what are the 3 classes of lipids?
- triglyceride: 95% of all lipids in food and in human body
- phospholipids: 2% of dietary lipids
- sterols: most common cholesterol
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list functions of fat.
- body's main storage for long-term energy
- shock absorber
- thermoregulation
- cell membranes
- transport fat-soluble vitamins (vitamin A,D,E,K)
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describe the structure of a triglyceride.
3 fatty acids + glycerol
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list the 3 types of fatty acid.
- saturated
- monounsaturated
- polyunsaturated
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triglyceride:
the more _______, the more liquid a room temperature.
unsaturated
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describe saturated fat
- carried maximum possible numbers of hydrogen atom
- are more stronger and stable chains (can melt then re-solidify after)
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describe unsaturated fat
- long chain = more solid at room temp
- monounsaturated: contain one point of unsaturation (carbon double bond c=c)
- polyunsaturated: contains 2 or more point of unsaturation
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describe the structure of phospholipids.
- 2 fatty acids + glycerol + phosphorus containing molecules
- soluble in fat and water
- found in cell membranes: phospholipid bilayer (outer layer: hydrophilic, inner layer: hydrophobic)
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in phospholipids, the ability to mix water and fat is called ______.
emulsifiers
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______ are insoluble in water (considered as fat); are naturally made in the human body; and most commonly known as cholesterol.
sterol
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trans fat.
fat that contains unusual fatty acids = bad fat (not made in the body)
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hydrogenation.
- adding a H atom to unsaturated F.A (consistency —> liquid to solid)
- REASON: resistance to rancidity (spoiling) —> for longer shelf-life
- UNWANTED RESULT: production of “trans-fats"
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cis-trans bond:
trans bonds
Fatty acids w/unusual shapes because hydrogens are added to the unsaturated fatty acids (groups are on opposite sides)
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cis-trans bond:
cis bonds
- The usual shape of a double bond structure (groups are on the same side)
- Lipases can only break down cis bonds not trans bonds
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list foods that are high in sat/trans fat.
Cheese, beef, milk, oils, ice-cream, frozen yogurt, cakes, cookies, quick breads, doughnuts, butter, animal fats, salad dressing, mayonnaise, poultry margarine, sausage, potato chips, corn chips, popcorn, yeast bread, eggs, candy, hot dogs ect….
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what are choleserol?
- A member of a group of lipids known as sterols (soft waxy substance made in the cells of the body and found in animal derived foods)
- Cholesterol travels through your bloodstream in small packages called lipoproteins. These packages are made of fat (lipid) on the inside and (proteins) on the outside.
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_______ are transport vehicles for larger products of lipid digestion
lipoproteins
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lipoprotein:
Chylomicrons
- are form first
- transport lipids from the small intestine to he liver after digestion
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name the types of lipoprotein.
- VLDL: (Very-Low-Density) lipoproteins triglyceride-rich (2/3);carried triglycerides made in the liver, to body cells for use
- LDL: (Low-Density Lipoprotein) a.k.a "bad cholesterol";carried cholesterol and other lipids from the liver to the body tissues
- HDL: (High-Density Lipoproteins) a.k.a "good cholesterol";carried cholesterol from the body cells to the liver;liver disposes of cholesterol
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What dietary changes can be made to lower the risk of developing heart disease?
Replace saturated & trans fats with monounsaturated and polyunsaturated fats within a reasonable calorie intake
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what are the Fat intake recommendations?
- 20-35% of total fat intake
- Lower saturated fat to below 7%
- Keep trans fats below 1%
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Ways to lower LDL/increase HDL
- reduce fat intake
- exercise
- control stress
- choose a diet (sat fat below 7%; trans fat below 1%)
- increase fiber intake
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what are the essential fatty acids and its functions?
- linoleic acid
- linolenic acid
- they are polyunsaturated. found in plants. regulates muscle relaxation and contractions; response to injury/infection (by causing fever/inflammation)
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Linoleic acid
- an omega-6 FA
- can be used to produce other omega-6 FA (arachidonic acid)
- Found in:seeds, nuts, vegetable oils (corn, cottonseed, safflower, sunflower)
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Linolenic acid
- an omega-3 FA
- found in: soybeans, walnuts, canola oil, flaxseed
- can be used to produce other omega-3 FA: EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid)- body makes limited amounts (breast milk)
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list and describe the roles of protein in the body.
Proteins provide structure and movement; serve as enzymes, hormones (insulin&glucagon), and antibodies; provide molecular transport; fluid and electrolyte regulation; buffers blood, contribute to blood clotting, energy supplies, and glucose for the body.
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Amino Acids – what are they? How do they structure a protein?
Amino acids consists of an amine group (nitrogen containing part) at one end, and an acid group attached to it at the other end. Each amino acid has a side chain (unique chemical structure attached to the backbone of each a.a which makes each a.a differ from one another) Amino acids are building blocks of protein
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What is protein quality and mutual supplements?
- Protein quality helps determine how well a diet supports the growth of children and the health of adults.
- Protein quality: is influenced by Protein digestion rate (animal protein digests a lot faster); Amino acid composition (animal protein contains all 9 essential amino acids so its quality is better than plant protein)
- Mutual supplements: combine 2 incomplete protein sources so that the a.a in one food make up for those lacking in other foods
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Describe the structure of proteins and explain why adequate amounts of all the essential amino acids are required for protein synthesis
- Proteins contain C.H.O.N
- Some may contain sulfur the element sulfur
- Proteins are many a.a linked together
- The nitrogen atom gives the name amino (nitrogen containing) to the amino acids the building blocks of proteins.
- The amino acids in a strand of protein are different from one another (contains 20 different kinds of amino acids
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what are the important proteins?
- collagen: make connective tissues
- enzymes: catalyst (facilitates a chemical reaction without itself being charged in the process)
- Hemoglobin: RBC; carries oxygen; made of 4 protein strands
- immune system: antibodies (immunoglobulins)
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How many essential amino acids are there? How many nonessential?
- 9 essential amino acids
- 11 nonessential amino acids
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Describe the consequences of both protein deficiency and protein excess
- Protein deficiency: is a state of malnutrition in which insufficient amounts of protein is taken in for the body to utilize in order to produce energy causing Marasmus & Kwashiorkor
- Protein excess: over consumption of protein rich foods such as red meats and fat-containing milk products which poses chronic disease risk: heart disease, kidney disease, adult bone loss, cancers.
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what is PEM? - be able to describe it (include Marasmus/Kwashiorkor and understand why the symptoms occur)
- Protein – energy malnutrition (PEM) worlds most widespread malnutrition problem in third world countries
- Marasmus: Chronic inadequate food intake; Lack of calories (protein calories); Shriveled all over (symptom); Occurs most commonly in children from 6-18 months of age (They are fed watery cereal and rice)
- Without adequate nutrition: Muscles waste and weaken; Brain development is stunted (Learning impaired); Immune system weakens; Little fat under the skin to insulate against the cold; Child engages in as little physical activity as possible; Not even a cry for food (can’t make tears)
- Kwashiorkor: Weaned from breast milk as soon as a new born comes along; No breast milk for the older child; Less fluid balance (symptom)-Causes Edema; Fatty liver because there is no protein (BIG stomach); Patchy and scaly skin; Sores fail to heal
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nitrogen balance
- The amount of nitrogen consumed compared with the amount removed from the body in a given time period
- People in a positive nitrogen balance = growth or anabolic state (5 nitrogen atoms in - 3 nitrogen atoms out)
- People in a negative nitrogen balance = losing more nitrogen than they are taking in or catabolic state
- Nitrogen equilibrium = protein in & protein out (healthy adults have the same amount of total proteins in their bodies at all times)
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describe Denaturation of protein
- breaking down and digestion of protein(unfolding of proteins); the irreversible change in a protein's shape; damages protein bodies
- caused by Heat, acids, bases, alcohol, heavy metals and salts
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define the term Vitamin.
- organic compounds
- vital to life
- non-caloric essential nutrients
- two classes:fat-soluble and water-soluble
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Describe the characteristics of fat-soluble and water-soluble vitamins
- fat-soluble: A,D,E,K
- stored in fatty tissue
- not needed daily
- excess —> build up to toxic levels (ULs)
- less susceptible to cooking losses
- water-soluble: B vitamins (8), vitamin C
- not stored in great extentexcess —> released in urine —> lower toxicity risk
- needed daily
- susceptible to losses via cooking
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describe the functions for Vitamin A
- functions: vision and immune defense (antioxidant - plant precursor)
- deficiency:night blindness (completely reversible); xerophthalmia
- toxicity: pregnant women - chronic use of supplements may cause fetal malformation
- sources: beta-carotene (carrots, broccoli, strawberry); retinol (fatty fish, cheese, milk)
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describe the functions of Vitamin D
- functions: regulates blood calcium levels (not essential - the body can make all it needs with the help of sunlight)
- deficiency: rickets (abnormal bone growth in children); osteomalacia (adult version of rickets)
- toxicity: most toxic of all vitamins; causes tooth enamel to thin and organs to malfunction
- sources: fish, fish oil, mushrooms
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describe the function for Vitamin E
- is an antioxidant
- can be destroyed by food processing and heating
- sources: (the more fatty the vegetable = the more vitamin E it will have--ex. oils & corn); no animal products
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describe the functions for Vitamin K
- function: helps synthesis with blood clotting proteins (interferes with blood thinners; lack of vitamin K in the body can cause excessive bleeding)
- deficiency: main people at risk newborns and those who take broad-spectrum antibiotics
- toxicity: RBC breakage (colors skin yellow-bilirubin); causes liver to release bilirubin into blood (jaundice)
- found in: intestinal bacteria
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describe the functions for Vitamin C
- function: formation of collagen; antioxidant; iron absorption; protects against infection
- deficiency: scurvy (common in heavy drug users and alcoholics, and infants fed too much cow milk)
- toxicity: kidney stones and diarrhea
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describe the function thiamin.
- vitamin B1
- role: carbohydrate metabolism
- sources: both animal and plant sources pork, liver, green leafy veg, whole grains, legumes
- deficiency: beriberi
- toxicity: unknown
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describe the functions of riboflavin.
- vitamin B2
- role: energy metabolism (of all the macronutrients)
- sources: dairy,green leafy veg, whole grains,meats, eggs
- deficiency: chelitis: cracks at corners of mouth and sores on tongue
- at risk:children who lack milk products and meat
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describe the functions of niacin.
- vitamin B3
- role: energy metabolism
- sources: fish, whole grain, legumes, meat
- deficiency: Pallagra (4D’s) diarrhea, dermatitis, dementia, death
- at risk: undernourished (particularly those with alcohol addiction)
- toxicity: can injure the liver, cause peptic ulcers, and vision loss
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describe the function of folate.
- vitamin B9, Folic Acid
- role: DNA & RBC synthesis
- sources: not found in animal products, only plants
- deficiency: Neural tube birth defects (NTDs), spinal bifida, anencephaly (fetus brain never develops)
- toxicity: can mask vitamin B12 deficiency
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describe the function of vitamin B12
- is activated by folate
- role: coenzyme for DNA and RBC
- sources: foods of animal origin (only vitamin found in animals) not in plants
- deficiency: Pernicious anemia
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describe the function of vitamin B6
- aids in the conversion of tryptophan to niacin (B3) and tryptophan to serotonin (a neurotransmitter)
- Role: hemoglobin synthesis (regulates blood glucose)
- deficiency: psychological depression, convulsion; low intake= increase risk of heart diseases
- toxicity: women who took 2+ grams/day for 2+ months in a mistaken attempt to cure PMS symptoms (can lose extremities sensations)
- sources: protein-rich foods
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