Nutrition test 2 review.docx

Nutrition test 2 review Proteins: Composition: Composed of macromolecules which are a long chain of amino acids. The specific arrangement of amino acids determines the structure and function of the protein. Amino acids are nitrogen-containing molecules that combine to form proteins Breakdown of how...

Nutrition test 2 review Proteins: Composition: Composed of macromolecules which are a long chain of amino acids. The specific arrangement of amino acids determines the structure and function of the protein. Amino acids are nitrogen-containing molecules that combine to form proteins Breakdown of how many amino acids are used to make proteins: Proteins are a combination of 20 amino acids The body can be about 10000-50000 proteins Essential vs Non-essential AA: 9 amino acids are indispensable amino acids (cannot be produced or are low quantity), must be obtained from food Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine 11 amino acids are Dispensable amino acids (the human body produces themselves) Alanine Asparagine Aspartic acid Glutamic acid Glycine Proline Serine Tyrosine Arginine Cysteine Glutamine Complete protein: Combination of two incomplete proteins to make a complete protein Mutual Supplementation – complementary proteins (Fig. 6.8): Mutual supplementation: combining two incomplete proteins to make a complete protein Complementary proteins: two protein sources that together supply all 9 essential amino acids ex, beans and rice Digestion of proteins – stomach, liver, small intestine. Enzyme Proteases: Stomach acids and enzymes break proteins into short polypeptides Hydrochloric acid denatures protein and opens up folded structure to allow access to the protein for digestion Acid converts pepsinogen to pepsin, which breaks apart proteins into single amino acids and shorter polypeptides Gastrin controls the production of hydrochloric acid and the release of pepsin in the stomach Enzymes in the small intestine break polypeptides into single amino acids The pancreas and small intestine secrete enzymes called proteases that break proteins into peptides and single amino acids Peptidases break apart tripeptides and dipeptides into single amino acids and enterocytes of the intestine absorb amino acids Amino acids are transported to the liver by the portal vein and distributed Consuming too much protein: Could increase the risk of acquiring kidney disease in susceptible people Can increase calcium excretion Vegetarian diets: 2.3% of Canadians identify as vegan Reduce intake of fat and total energy, reducing risk for obesity and type 2 diabetes Lower blood pressure Reduced risk for heart disease Fewer digestive problems Reduced risk for some cancers (colorectal) Reduced risk for kidney stones and gallstones It could lack certain vitamins and minerals and might need to be obtained from sources other than food Protein-energy malnutrition – Marasmus vs. Kwashiorkor: Kwashiorkor: a form of protein-energy malnutrition characterized by wasting, and edema (typically seen in children of 1-3 years of age who no longer get breast milk and intake low protein) Marasmus: a disease that results in inadequate intake of energy, especially protein (most common in children 6-18 months of age in impoverished conditions) Fluids and Electrolytes: Water - how much water to consume?: men (19-50): need 3.7 L of total water/day 3.0L from beverages, 0.7L from food Women (19-50): need 2.7L of total water/day 2.0L from beverages, 0.7L from food Athletes and people working in hot environments would need more Fluid and electrolyte balance: Water intoxication: occurs in people with disorders that cause kidneys to retain too much water, diluting blood sodium, leading to hyponatremia Dehydration: fluid excretion exceeds fluid intake causing a deficiency of total body water Hypertonic dehydration: body water is depleted by insufficient fluid intake or excessive sweating Isotonic dehydration: body water deficit is accompanied by proportionate salt loss Hypertension can occur in people who consume high sodium and low potassium diets Hypernatremia: high blood sodium concentration Hyponatremia: low blood sodium concentration Know the following electrolytes: Sodium (Na) – how much is needed, what happens if too much or too little): Fluid and electrolyte balance Blood pressure regulation Nerve impulse transmission and muscle contraction Intakes: Females → 1500 mg/d Males → 1500 mg/d Hypertension can occur in people who consume high sodium and low potassium diets Hypernatremia: high blood sodium concentration Hyponatremia: low blood sodium concentration Chloride (Cl): Intakes: Females → 2300 mg/d Males → 2300 mg/d Fluid and electrolyte balance Potassium (K) – normal lab range?: Lab range: 3.5-5.0 mmoll/L Intakes: Females → 2600 mg/d Males → 3400 mg/d Fluid and electrolyte balance Transmission of nerve impulses, muscle contractions A high-potassium diet lowers blood pressure Found in fresh fruits and vegetables Hyperkalemia: high blood potassium concentration Potassium not excreted from the body properly Can alter the rhythm of the heart, resulting in a heart attack Hypokalemia: potassium deficiency Some diuretics increase the excretion of potassium Extreme dehydration, vomiting, diarrhea, alcohol abuse, and laxative abuse increase the risk of hypokalemia Phosphorus (H0P4): Intakes: Females → 700 mg/d Males → 700 mg/d Required for fluid balance Critical role in bone formation (85% of body phosphorus is found in bone) Activates or deactivates enzymes Found in ATP, DNA, RNA Risk of high phosphorus levels in people with kidney disease, people who consume excess vitamin D, and people who consume phosphorus-containing antacids Antioxidant function: Oxidation, free radicals, and vitamins that act as antioxidants: Oxidation is a chemical reaction in which atoms lose electrons Vitamin E: Vitamin E is a key antioxidant 90% of vitamin E is stored in adipose tissue, remaining in cell membrane Most potent form is alpha-tocopherol Functions of vitamin E in the body: Antioxidant, donates electron to free radicals, Protects cells and cell membranes from oxidation, Important for normal nerve and muscle function, Boosts absorption of vitamin A if vitamin A intake is low Vitamin E (fat soluble) - RDA for 19 years of age and older: 15 mg alpha-tocophero Vitamin E is destroyed by oxygen, metals, UV light, heat Vitamin E supplementation above RDA can increase risk of prostate cancer in men and premature mortality Vitamin E supplements may augment anticoagulant effect of some medications (example: Coumadin) Deficiency is rare, but symptoms could be erythrocyte hemolysis, loss of muscle coordination, poor immune function Vitamin C: Vitamin C is a water soluble antioxidant Functions of vitamin C in the body: Antioxidant, donates electron to free radicals Protects against LDL oxidation Regenerates vitamin E after oxidation Synthesis of hormones (thyroid), bile, neurotransmitters Synthesis and maintenance of collagen Does not prevent colds, but may decrease duration of cold Beta-Carotene: (fat soluble, provitamin for vitamin A) Carotenoids like beta-carotene have antioxidant properties Carotenoids are plant pigments that are the basis for red, orange, yellow colours of fruits and vegetables Dark green vegetables also contain carotenoids Beta-carotene acts as provitamin A, precursor of retinol, an active form of vitamin A 12 units of beta-carotene are equal to 1 unit of vitamin A Functions of beta-carotene in the body: Antioxidant Enhance immune function Protect skin from sun’s UV rays Protect eyes from oxidative damage Red, orange, yellow, deep green fruit and vegetables are high in beta-carotene and other carotenoids Absorb only 20-40% of carotenoids in foods consumed Vitamin A: There are several forms of vitamin A (fat soluble) 90% of vitamin A is stored in liver There are 3 active forms of vitamin A, called retinoids: Retinol (alcohol form) Retinal (aldehyde form) Retinoic acid (acid form) When we eat foods with beta-carotene, it is converted to retinol in the wall of small intestine Vitamin A is essential to sight Enables our eyes to react to changes in brightness of light Vitamin A’s role in vision: Light enters eye and hits retina Retinal combines with opsin to form rhodopsin, which helps us interpret black and white images Bleaching process, where rhodopsin is split into retinal and opsin and rods lose colour Nerve impulse travels to brain Selenium: Selenium is a key antioxidant mineral (trace mineral) Discovered after a disorder called Keshan Disease was linked to selenium deficiency due to low selenium in soil Storage form is called selenomethionine and active form is called selenocysteine Selenocysteine is critical for glutathione peroxidase Needed for production of thyroid hormone, immune function Foods high in selenium Seafood Meat Cottage cheese Mushrooms Eggs ***Know solubility, functions, foods, deficiencies Bone health: Calcium: RDA: 19-50: 1000mg/day Women 51+: 1200mg/day Men 51-70: 1000mg/day 70+: 1200mg/day Most abundant major mineral in the body (99% of body calcium is found in bone) Functions of calcium: Forms and maintains bones and teeth Assists with acid-base balance Critical for normal transmission nerve impulses Assists in muscle contraction Maintains blood pressure, initates blood clotting, regulation of hormones and enzymes Blood calcium level is tightly controlled When calcium levels are low, parathyroid hormone (PTH) is released, which activates vitamin D To increase blood calcium levels, PTH and vitamin D cause: Kidneys to retain more calcium Osteoclasts to break down bone and release calcium Stimulation of calcium absorption from intestines Vitamin D is necessary for absorption of calcium Excessive dietary calcium is excreted in feces Fruits and vegetables are best sources of vitamin C (fresh) Red bell peppers Strawberries Orange Broccoli Grapefruit juice Hypercalcemia: high blood calcium can be caused by cancer and overproduction of PTH Hypocalcemia: low blood calcium can be caused by kidney disese or vitamin D deficiency Vitamin D: Regulates calcium Is a fat-soluble vitamin that is stored in the liver and adipose tissue Can be synthesized by the body by exposure to UV light from the sun and consumed through diet and supplements Considered a hormone because it is synthesized in one location and acts in other locations Functions: Calcium and phosphorus absorption, regulations blood calcium Stimulates osteoclasts Calcification of bone Canadians lack vitamin D Osteomalacia (soft bones) can occur in adults due to vitamin D deficiency Foods that contain protein such as Milk Meat Eggs Processed foods and soft drinks as additive Diseases of the Bone: Osteoporosis: low bone mass and deterioration of bone tissue, leading to increased fracture risk Influences on osteoporosis risk: Aging increases Hormonal changes with age have an impact on bone loss Loss of testosterone and decreased ability to metabolize vitamin D also contribute to the increased risk with age Smoking Low body weight Low calcium intake Low sun exposure Alcohol abuse History of amenorrhea (failure to menstraute) Estrogen deficiency Testosterone deficiency Repeated falls Sedentary lifestyle Long-time use of glucocorticoids Gender → female (lower bone density mass) Caucasian or asian race Vitamin K: Remodeling of bones Assists in production of osteocalcin Few foods contribute to vitamin K intake green leafy vegetables Broccoli turnip greens brussel sprouts Cabbage soy canola oils also produced by GI flora in large intestine Deficiency can result in inability of blood to clot Phosphorous: Major intracellular negatively charged electrolyte in the body, 85% stored in bones functions: Critical to mineral composition of bone Activation and deacativtion on enzymes Component of lipoproteins, cell membranes, DNA and RNA, and several energy molecules (ATP) People with kidney disease and those who take too many vitamin D or phosphorus containing antacids can have high blood phosphorus Can cause muscle spasms and convulsions Deficiency is rare but can occur in people who abuse alchol, premautre infants and malnourised elderly adults Foods that contain protein such as Milk Meat Eggs Processed foods and soft drinks as additive Magnesium: Magnesium is a component of bone and helps regulate bone status The bones contain 50-60% of the bodys magnesium Functions: Influences formation of hydroxyapatite Cofactor for over 300 enzyme systems Role in ATP, DNA and protein synthesis Supports vitamin D metabolism Important for heart health, blood clotting Hypermagnesemia: can occur in individuals with impaired kidney function who consume non-dietary magnesium Hypomagnesemia: can occur secondary to kidney disease, chronic diarrhea, alchol abuse, low dietary mangesium Found in foods such as Green leafy vegetables Whole grains Seeds Nuts Spinach Beans seafood Know what foods have these micronutrients: Know excess illness and deficiency illnesses: