Term
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Definition
-Proteins made of chain of amino acids
-Proteins are organic compounds containing C, H, O, and N
-N distinguishes protein from carbohydrates and fats |
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Term
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Definition
-20 common amino acids needed to form all proteins in human body
-9 of these amino acids considered essential
-Other 11 amino acids nonessential |
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Term
| Four Major Functions of Proteins |
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Definition
1. Integral structural component of skeletal muscle, bone, connective tissues, organs, red blood cells, hemoglobin, hair, & nails
2. Basic substance that makes up enzymes & hormones in human body
3. Growth, maintenance & repair of protein-containing structures
4. Protein also serves as an energy source |
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Term
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Definition
-Nearly all in U.S. get enough protein
-Most consume more than needed
-Recommended range of total calories: 10-35% |
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Term
| Acceptable Macronutrient Distribution Range (AMDR) |
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Definition
Carbohydrate: 45-65% total calories
Protein: 10-35% total calories
Fat: 20-35% total calories |
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Term
| Food as a Source of Protein |
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Definition
-70% protein intake comes from meats, milk, and other animal products in U.S. diet
-Fruit has no protein…. Protein and carb have 4 cals/gram… fat has 9 cals/gram… alcohol has 7 cals/gram
-Gramsx4=calories in protein |
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Term
| Review of Protein Digestion and Absorption |
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Definition
-Digestion: protein → amino acids
-Mechanical digestion starts in mouth
-Chemical digestion starts in stomach
-Two key enzymes: trypsin and pepsin
-Absorption occurs in small intestine |
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Term
| Protein as an Energy Source |
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Definition
-If destined for energy use, first needs nitrogen removed from individual amino acids
-Excess free nitrogen excreted in urine
-Nitrogen excretion increases need for water |
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Term
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Definition
-Most protein recycled from protein substances being ‘turned over’ in our body
-Proteins key roles in tissue repair & replacing tissue proteins damaged by illness or injury |
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Term
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Definition
-Chain of amino acids called polypeptide
-Chains of amino acids fold up into complex shapes
-DNA directs protein synthesis and order of amino acids in chains, which determines type and function of protein formed |
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Term
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Definition
-Change in shape of protein structure due to heat, light, change in pH (too acidic or basic environment), alcohol, or motion
-Examples in food: Boiling foods or beating egg white; Adding lemon juice or vinegar
-Examples of effects in body: Hemoglobin less able to carry oxygen & Enzymes less able to function as catalyst |
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Term
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Definition
-Quality of protein varies depending on its essential amino acids content
-High quality proteins contain all essential amino acids
-Individual amino acids not stored in body
-If one or more essential amino acids missing in diet, proteins synthesis halted |
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Term
| Complete & Incomplete Proteins |
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Definition
-Food sources of high-quality protein (complete proteins) found in animal derived products
-Incomplete proteins – deficient in one or more essential amino acids
-What about vegetarian diets: Complementary Protein Sources
-Rice & Black Beans
-Hummus and Bread
-Corn and Black-eyed peas
-Bulgur and Lentils
-Tofu and rice
-Corn and Lima beans
-Tortilla with refried beans
-Pea soup and bread |
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Term
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Definition
-2/3 of U.S. populations’ protein sources come from animal products
-Wealth leads to increase meat protein intake along with increase consumption of fat
-High protein intake usually accompanied by higher-fat & lower-fiber intakes
-Diets adequate in protein without excess fat tend to be rich in beans & grains mixed with lean meats & low-fat dairy products
-Foods high in complete protein, such as hamburger, cheese, nuts, & eggs, also high in fat & little or no fiber content
-Even lean meats can provide large part of total calories from fat
-Actually noticed that rates of heart disease & some cancers increase with higher protein intakes |
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Term
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Definition
-Protein deficiency occurs alone or with deficiency of calories & other nutrients
-Protein foods good sources of micronutrients iron, zinc, niacin, & vitamin B12
-Body protein provides energy during starvation states
-Loss of 30% body protein results in decrease strength for breathing, increasing susceptibility to infection, abnormal organ functions, & death
- Problem with starvation: taking protein from liver, intestines, heart, muscles, & other organs and tissue |
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Term
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Definition
-Malnutrition caused by insufficient protein intake, yet adequate total caloric intake
-Gives “fat” or swollen appearance
-May develop after child weaned from breast milk or in severe alcoholics |
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Term
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Definition
-Malnutrition caused by insufficient total protein & caloric intakes
-Also called protein-energy malnutrition
-Gives “skin and bones” appearance
-Occurs among people with anorexia nervosa & diseases causing cachexia |
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Term
| Kwashiorkor & Marasmus are complicated by: |
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Definition
| Infection, Diarrhea, Dehydration |
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Term
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Definition
-Adults can consume up to 35% of total calories from protein without ill effects
-Consumption of 45% or greater of total calories from protein is too high
-Excess protein intake causes nausea, weakness, and diarrhea; diets very high in protein result in death after several weeks
-Disease from excess protein intake termed “rabbit fever”
-High protein diets implicated in weak bones, kidney stones, cancer, heart disease, & obesity
-NAS concluded safe range for protein intake is 10-35% of total calories |
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Term
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Definition
-High intakes of individual amino acid supplements can harm health by disrupting protein synthesis
-Amino acid supplements:
o May cause loss of appetite, diarrhea, & GI upsets
o Increase workload of liver and kidneys, & likelihood of dehydration |
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Term
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Definition
-Amino acids & protein powders alone do not cause muscle growth
-Only combination of exercise & good diet build muscle mass
-Most athletes get sufficient protein from their usual diet
-May benefit from additional 15 gram daily over RDA
-AA’s not delivered directly to our muscles or causing muscles to enlarge
-Think about diet being higher in total calories as well – so percentage of protein may not be higher, but increased intake |
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