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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
list functions of fat.
- body's main storage for long-term energy
- shock absorber
- cell membranes
- transport fat-soluble vitamins (vitamin A,D,E,K)
describe the structure of a triglyceride.
3 fatty acids + glycerol
list the 3 types of fatty acid.
the more _______, the more liquid a room temperature.
describe saturated fat
- carried maximum possible numbers of hydrogen atom
- are more stronger and stable chains (can melt then re-solidify after)
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
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)
in phospholipids, the ability to mix water and fat is called ______.
______ are insoluble in water (considered as fat); are naturally made in the human body; and most commonly known as cholesterol.
fat that contains unusual fatty acids = bad fat (not made in the body)
- 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"
Fatty acids w/unusual shapes because hydrogens are added to the unsaturated fatty acids (groups are on opposite sides)
- The usual shape of a double bond structure (groups are on the same side)
- Lipases can only break down cis bonds not trans bonds
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….
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.
_______ are transport vehicles for larger products of lipid digestion
- are form first
- transport lipids from the small intestine to he liver after digestion
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
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
what are the Fat intake recommendations?
- 20-35% of total fat intake
- Lower saturated fat to below 7%
- Keep trans fats below 1%
Ways to lower LDL/increase HDL
- reduce fat intake
- control stress
- choose a diet (sat fat below 7%; trans fat below 1%)
- increase fiber intake
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)
- 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)
- 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)
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.
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
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
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
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)
How many essential amino acids are there? How many nonessential?
- 9 essential amino acids
- 11 nonessential amino acids
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.
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
- 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)
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
define the term Vitamin.
- organic compounds
- vital to life
- non-caloric essential nutrients
- two classes:fat-soluble and water-soluble
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
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)
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
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
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
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
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
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
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
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
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
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