11:22:11 - Review for Exam III (Part 1)

11:22:11 - Review for Exam III (Part 1) - Minerals Major or...

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Unformatted text preview: Minerals Major or macro minerals: necessary in amount >100 mg/day Macro minerals: Calcium – Ca Phosphorus - Ph Magnesium - Mg Sodium - Na Potassium - K Chloride - Cl Sulfur – S Cations: Ca, Na, K Anions: Cl, S, Mg, Ph Micro minerals: necessary in amounts < 100mg/day. Micro minerals or trace minerals: Iron – Fe Zinc – Zn Copper – Cu Selenium – Se Chromium – Cr iodine – I Manganese – Mn Molybdenum 0 Mo DRI for adult males and females for minerals Mineral Male DRI Female DRI Calcium 1000 mg 1000 mg Phosphorus 700 mg 700 mg Magnesium 420 mg 320 mg Sodium 1300 mg 1300 mg Potassium 4700 mg 4700 mg Chloride 2300 mg 2300 mg Iron 8 mg 18 mg Zinc 11 mg 8 mg Copper Selenium Iodine 900 µg 900 µg 55 µg 55 µg 150 µg 150 µg *** Average American consumes 3-5 g/day of sodium*** Food Sources for Macro Minerals Ca P Mg Na K Cl Milk Meat Coffee Salt Prune juice Salt Yogurt Poultry Tea Canned foods Bananas Eggs Cheese Eggs Nuts Smoked foods Cantaloupe Meat Tofu Milk Legumes Processe d foods Mango Seafood Chinese Cabbage Legumes beans Cheese legumes Food Sources for Micro Minerals Heme Fe Non heme Fe Zn Cu Se I Meat Nuts Seafood Oysters Cereal Seawater fish Poultry Fruit Liver Liver Grains Milk fish Green leafy veggies Beef Nuts Meat Yogurt Beans Veal Seeds Dairy Eggs grains Cheese cocoa beans Calcium Most abundant mineral in the human body. Makes up 1.5-2% of total body weight Bones and teeth contain 99% of total body calcium Remaining 1% is distributed between intra- and extracellular fluids. Absorption rate: can be as high as 75%. Adults about 30% Key points: • higher amounts in adolescence • goes up again in older adults The state of the American diet • Average dietary intakes of calcium in the U.S. are well below the adequate intake recommendation for every age and gender group, especially in females. •Only about 25% of boys and 10% of girls ages 9 to 17 are estimated to meet the AI recommendations. •Dairy foods provide 75% of the calcium in the American diet. • it is typically during the most critical period for peak bone mass development that adolescents tend to replace milk with soft drinks . Calcium. Updated in October 2007 by: Victoria J. Drake, Ph.D. Linus Pauling Institute Oregon State University Lifecycle effects of Absorption Stimulated by: Inhibited by: 1) presence of VD/calcitriol 2) <400 mg diet 3) growth periods 4) pregnancy + lactation 1)Decreased calcitriol production 2)High plasma phosphorus 3)Estrogen deficiency, seen during menopause Absorption from GI Tract: Active transport in duodenum and proximal jejunum Diffusion in jejunum and ileum Can be impacted by nutrients/substances in the diet Only concern if vegan diet and Consuming >30 g fiber Husks of Cereal grains Milk: Fortification Lactose Compete for absorption Ca forms soaps with fatty acids Found in: spinach rhubarb chard beets celery eggplant greens okra squash berries some nuts tea, ovaltine & cocoa Table 11-2, p. 433 Transport a can be transported in 3 forms: 1) bound to protein (albumin and pre albumin 2) in complex with sulfur, phosphate or citrate 3) free Regulation of calcium concentrations Fig. 11-3, p. 434 Regulation of calcium concentrations Extracellular: 3 main hormones: 1) PTH – secreted by the parathyroid gland. 2) calcitriol – active VD, 3) calcitonin – synthesized in the parafollicular cells in the thyroid gland. Acts by stimulating osteoblasts, inhibiting osteoclasts and may inhibit synthesis of active VD and levels in the cytoplasm are kept in check. tracellular: Ca ↓ renal calcium resorption. flux stimulated by: 1) cell activation – allows Ca to flow in from extracellular spaces 2) second messenger – cause release of Ca from organelles (ex: mitochondria) eturn to normal levels achieved by: ATP dependent pumps, either out of the cell or into organelles. is sequestered in the endoplasmic reticulum and sarcoplasmic reticulum (in muscle cells). Functions Majority of Calcium found in bone: 2 types: Cortical Bone Trabecular Bone • is compact and dense • has a spongy appearance •Represents about 75 – 80% of total •Represents about 20 -25% of total body calcium. body calcium. •Consists of layer of mineralized protein (mostly collagen). • consists of an interconnected system of mineralized proteins (mostly collagen). • is found in relatively high concentrations in the axial skeleton (vertebrae and • is found mainly on the surfaces of bones and the shaft of long bones of pelvic region). the limbs and wrists. Fig. 11-5, p. 436 ne mineralization: protein and ground substance made up of: llagen + osteonectin + osteopontin + bone sialoprotein + osteocalcin (Bone Gla proteins*) matrix Gla proteins* osteoblasts mineralization osteoid osteocyte Lining cells Flat cells that form A membrane over Bone surface Osteoblasts becomes part of the osteocyte Causes resorption osteoclast Stimulated by PTH, Calcitriol. Inhibited by calcitonin Childhood and adolescence: bone formation > resorption Adulthood: during fifth decade bone mass begins to decline *VK dependent for calcium binding ability Other Functions ntracellular calcium is essential for several functions: lood clotting – several clotting factors require Ca bound to carboxylation sites. erve conduction – nerve impulses reach a target site, such as muscle, stimulating Ca influx, releasing neurotransmittor into synaptic cleft. uscle contraction – Troponin C binds 4 Ca molecules, change in conformation allows actin and myosin to bind causing muscle contraction. nzyme regulation – calmodulin embrane permeability Interactions with other nutrients Phosphorus: ratios of Ph :Ca important for infants and children. Not adults. Table 11-2, p. 433 Deficiency - Hypocalcemia Can see Rickets in young children. Tetany: muscle contraction (arms and legs) accompanied by failure to relax: muscle pa muscle spasms, paresthiea. Osteoporosis: ↑ bone fragility and factures (brittle bones) Also linked to development of HTN, colon cancer, and overweight/obesity. Toxicity - Hypercalcemia Tolerable upper level: 2500 mg/day Have seen milk alkali sydrome: excess milk/antacids – see calcification of soft tissues Osteoporosis • Affects 50% of women > 45 years. • Affects 90% of women > 75 years. • Men affected too, usually later in life. • Fractures: hip fracture and surgery: 1/3 dies within one year. Factors affecting osteoporosis risk • High correlation: – Age – Alcoholism – Corticosteroids – Rheumatoid arthritis – Removal of ovaries or testes – Thinness • Moderate correlation: – Smoking – Diabetes – Early menopause – Excess antacid use – Low calcium diet – Vit D deficiency • Protective Factors •African-American •Estrogen • Weight bearing exercise • Haven given birth • High body weight •High calcium diets Disease/Factors related to calcium levels Hypocalcemia: hypoalbuminemia, hypoparathyroidism, hypomagnesmia, hyperphosphatemia, acute pancreatitis, hungry bone syndrome can occur after parathyroidectomy), Renal failure End Stage Renal Disease: renal osteodystrophy – ↓ GFR ↑ Ph levels due to kidney not excreting ↓ active VD synthesized by kidney Breaks down system to regulate Ca – ↑ calcification of tissue and ↑bone resorption Hypercalemia: hyperparathyroidism, some malignancies (esp: breast, lung, kidney, multiple myeloma, leukemia, and lymphoma), immobilization, hyperthyroidism, Excretion Calcium lost by: 1) urine :100 -240 mg/day 2) feces : 45 – 100 mg/day 3) sweat : avg 60 mg/ay Diet and extracellular level dependent ↑ excretion: Protein Caffeine Sodium Phosphorus Second most prevalent mineral in the human body. Approximately: 560 – 860 g or 0.8 – 1.2% of body wieght. 85% is in the skeleton 14% in soft tissue 1% in the blood Commonly found in combination with other elements. Generally 50-70% of dietary phosphorus is absorbed. Absorption occurs in the duodenum and jejunum. Absorbed by 2 processes: 1)sodium-dependent active carrier – enhanced by calcitriol. 2)Concentration dependent facilitative diffusion process. *** most phosphorus absorbed this way. If intake is low then active transport increases. Factors influencing absorption: Stimulate: Inhibit: 1)Calcitriol - VD 1)Phytate 2)Magnesium 3)Aluminum 4)Calcium Excessive intake Common antacids: aluminum hydroxide, magnesium hydroxide, calcium carbonate or calcium acetate will bind phosphorus to prevent absorption. Transport 70% found as phospholipids (lipoproteins) 30% as HPO42- , H2 PO4 , or PO43- in the blood sphorus is found in all cells of the body and tends to be kept in balance: keletal - Cellular inorganic - organic phosphates formed as intermediaries Functions Bone mineralization • 85% of body phosphorus is found in bone. • found bound to calcium in a variety of forms. • regulated by PTH, calcitriol and calcitonin PTH In response to Ca levels ↑ bone resorption which ↑’s serum P will also ↑ excretion of P by the kidney In response to Ca levels Calcitriol ↑bone resorption which ↑’s serum P will stimulate P absorption in GI tract Calcitonin In response to Ca levels ↑ bone mineralization that ↓’s serum P Functions continued 1) Bone mineralization 2) Nucleotide/nucleoside phosphates 3) Phosphoproteins 4) Structural roles 5) Acid-base balance 6) Oxygen availability Deficiency - hypophosphatemia Rare Symptoms: anorexia, leukocyte dysfunction, reduced cardiac output, ↓ diaphramatic contractility, arrhythmias, skeletal and cardiac myopathy, weakness, and neurological problems Groups at risk: renal patients who may be receiving large amounts of antacids malnourished – refeeding syndrome: TPN or enteral feeding lacks Clinical situations: Malabsorption, diarrhea, VD deficiency Intracellular shifts: alkalosis (respiratory), cellular uptake (anabolism and some neoplasms), burn, sepsis. Increased losses: hyperparathyroidism, renal tubular defects (Fanconi syndrome), diabetic ketoacidosis (the recovery phase). Alcoholism Toxicity - hyperphosphatemia Tolerable upper level: 4 g Rare Symptoms: hypocalcemia and tetany Only seen in infants when calcium : phosphorus ratio favors calcium. Clinical situations: Acute and chronic renal failure – decreased renal output Increased cellular release – tumor lysis syndrome, tissue necrosis, rhabdomyolosis Increased Ph load – Ph containing laxatives or enemas, VD excess Acidosis Excretion 67 – 90% excreted in the urine. 10 – 33% through feces Maintenance of Ph balance achieved primarily through urinary excretion. Magnesium - Mg about 60% found in bone Over 25% in muscle 6-7% in other cells 1% - extracellular fluids Absorption pically 40 -60% of dietary MG absorbed: primarily distal jejunum, ileum – can be absorbed from the colon. Efficiency ↑’s with ↓ dietary amounts. 2 routes: 1) High dietary concentration: simple diffusion 2) carrier-mediated active transport. Tends to inhibit if these minerals are ↑ and Mg is ↓ Table 11-6, p. 448 Transport Most Mg found free in plasma 33% bound to protein: albumin and globulins Balance maintained by GI absorption – renal excretion – transmembranous cation flux. Although several hormones can influence: Ex: PTH - ↑ GI absorption and ↓ renal excretion and ↑ serum levels through bone resorption. Functions 1) Bone mineralization 2) Variety of biochemical processes • glycolysis • TCA cycle • Hexose monophosphate shunt • nucleic acid synthesis • DNA and RNA transcription • protein synthesis • muscle contractability • insulin and insulin action Relationships with other nutrients: Calcium: tied to calcium through actions of PTH, Mg necessary for PTH function & Mg necessary for hydroxylation of VD in the liver 1) compete with Ca for resorption from the kidney. 2) work with or compete with Ca in cellular reactions and muscle contraction. Potassium: Mg influences the balance between extracellular and intracellular eficiency – Hypomagnesemia ymptoms: nausea, vomiting, anorexia, muscle weakness, spasms and tremors, personality changes, and hallucinations. Clinical situations: ↓ absorption – prolonged diarrhea, intestinal or biliary fistula, intestinal resection or bypass, steatorrhea, ulcerative colitis, prolonged gastric suction, excessive vomiting. Renal losses – osmotic diuresis, DM/glucosuria, correction of diabetic ketoacidosis, renal disease with magnesium wasting, hypophosphatemia, hypercalcemia, hyperthyroidism, hyperaldosteronism, diuretic phase of acute tubular necrosis, renal tubular acidosis, Alcoholism – Malnutrition – inadequate intake Intracellular shift – acute pancreatitis Refeeding syndrome Clinical situations: ↓ absorption – prolonged diarrhea, intestinal or biliary fistula, intestinal resection or bypass, steatorrhea, ulcerative colitis, prolonged gastric suction, excessive vomiting. Renal losses – osmotic diuresis, DM/glucosuria, correction of diabetic ketoacidosis, renal disease with magnesium wasting, hypophosphatemia, hypercalcemia, hyperthyroidism, hyperaldosteronism, diuretic phase of acute tubular necrosis, renal tubular acidosis, Alcoholism – Malnutrition – inadequate intake Intracellular shift – acute pancreatitis Refeeding syndrome Meds: diuretics, amphotericin B, aminoglycosides, cisplatin, cyclosporine, pentamidine, foscarnet, tacrolimus Toxicity - Hypermagnesemia Tolerable upper level: 350 mg from nonfood sources . Symptoms: can see diarrhea, dehydration, nausea, vomiting, flushing, double vision, slurred speech, arrhythmias, mental confusion, respiratory muscle paralysis, peripheral vasodilation resulting in profound hypotension. Clinical situations Acute or Chronic renal failure These usually only seen when accompanied by impaired renal function: •Rhabdomyolysis •Adrenal insufficiency (Addison’s disease) •Hypothyroidism •Dehydration Excretion Most magnesium is excreted through the kidneys – however kidney tends to reabsorb 95% of the Mg that filters through. Water • 60% of adult weight. • Excretion: ml/day 1400 urine 100 sweat 200 feces 600 evaporation from lungs and diffusion across skin •Osmotic pressure: tendency of water to equilibrate across a semi-permeable membrane. Pressure drives water from low solute concentration to high. Table 14-1, p. 550 Fasting and Refeeding During initial days of fasting: renal excretion of sodium ↑’s then decreases as body conserves. Upon refeeding, there is a marked retention of Na, probably caused by ingestion of carbohydrate. This leads to a rapid rise in body weight. This is seen due to an increase in total body water secondary to the stimulation of Vasopressin and thirst by the rise in plasma osmolality. Fig. 14-4, p. 554 Table 1, p. 564 Sodium - Na 30% of Na is located on surface of bone crystals. Remainder is in the extracellular fluid, nerve and muscle tissue. *** Average American consumes 3-5 g/day*** Absorption 95 – 100% is absorbed – 5% lost in the feces 3 pathways for absorption: 1)Na+ /glucose cotransport pathway – throughout the small intestine 2) Na+ /Cl- cotransport pathway – small intestine and proximal large intestine 3) sodium absorption pathway – principally in the colon Transport Sodium transported freely in the blood. Functions Maintain fluid balance Maintain acid-base balance Nerve transmission/impulse conduction Muscle contraction Interactions with other nutrients: Calcium - ↑Na ↑ Ca excretion, ↓ Ca excretion in feces, ↑ Ca absorption Deficiency - Hyponatremia Does not normally occur. But can see with excessive sweating. Symptoms: muscle cramps, nausea, vomiting, dizziness, shock and coma. Clinical Situations Can be seen when serum osmolality is low: If serum osmolality is low: Can indicates volume loss Water + Na loss, Na loss > water loss: 1)Loss via GI tract: diarrhea, vomiting gastric suction, fistula 2) Loss via skin: burns, excessive sweating, 3) Third spacing: ascites, bowel obstruction, peritonitis, pancreatitis 4) Lungs: bronchorrhea 5) Renal loss: diuretics, renal disease, osmotic diuresis (ketones, glucose urea), primary adrenal Water + Na increase, Water > Na: 1)Edema forming states: Congestive Heart Failure, Cirrhosis, Nephrotic Syndrome 2) Acute or Chronic Renal Failure Toxicity - Hypernatremia Tolerable upper level: 2300 mg/day Tends to only be seen as a result of a clinical situation. Again tied to total volume or change in volume of ECF (extracellular fluid). 1) Can see with total volume depletion in rate of water loss is greater than Na loss. This causes a change in concentration. seen with: GI, skin or lungs 2) Can see with loss of just ECF volume loss: total body water loss but normal Na. seen with: water deprivation, renal losses, DM insipidus Excretion 1) Urinary – aldosterone controls 2) Sweat – normally minimal but ↑’s with temperature and intensity Potassium - K The major cation of intracellular fluid Absorption >85% is absorbed Absorption not clearly understood. Believe it is through passive diffusion as well as a K/H –ATPase pump Absorbed throughout the small intestine and believe some is absorbed in the colon. Transport Travels freely in the plasma Uptake into non-intestinal cells is regulated by the Na/K –ATPase pump. Functions Acid – base balance Contractility of smooth, skeletal and cardiac muscles Excitability of nerve tissue Interaction with other nutrients Calcium: can decrease calcium excretion Deficiency - Hypokalemia Symptoms: cardiac arrhythymia, muscle weakness, nervous irratibility, hypercalciuria, glucose intolerance, and mental disorientation. Difficult to see with normal diet and renal function. Clinical Situations Renal loss: osmotic diuresis, hypomagnesemia, hyperaldosteronism, Cushing’s syndrom, licorice excess GI loss: diarrhea, prolonged vomiting, gastric suction Alkolosis Refeeding syndrome Toxicity - Hyperkalemia Toxic: results is cardiac arrhythmias and cardiac arrest Clinical Situations Chronic renal failure Hypoaldosteronism Renal tubular acidosis Excretion 90% excreted by kidneys – regulated by kidney/aldosterone Aldosterone stimulates reabsorption of Na and increases excretion of K. Chloride - Cl Most abundant anion in extracellular fluid Absorption Almost completely absorbed. Follows the electrical gradient set up by Na. Transport ransported freely aken up by cells via the Na/K/Cl cotransport pathway. Responds to the electrical gradient set up by the Na/K – ATPase pump. Functions Acid – base balance HCl – stomach Phagocytosis – released by white blood cells Respiratory – helps carry CO2 away from cells Deficiency Does not occur under normal conditions. Possible to see with severe diarrhea and vomiting. Symptom: convulsion. Toxicity No common toxicity, although there is a tolerable upper level of 3.6 g. Excretion Chloride is lost by: 1)Urine – follows sodium 2)Sweat – follows sodium 3)Feces – the small amount that is not absorbed Hypertension Prevalence: 25% or 50 million Americans. Defined: Systolic blood pressure >140 mm Hg/Diastolic blood pressure >90 mm Hg. rimary or essential hypertension accounts for about 90% of cases Causes: generally unknown, thought to be multifactorial econdary hypertension occurs secondary to another condition such as: kidney, endocrine or neurological. Dietary modification works for some but not all individuals. Foods/ nutrients associated with blood pressure: Na, K, Ca, Mg, and alcohol Table 1, p. 564 Sodium Mixed results from studies. In general: some individuals are sensitive to the amount of sodium in their diet and see a resulting decrease in blood pressure when sodium i restricted. Individuals most likely to benefit from decreased dietary sodium: African Americans > 65 years obese individuals with low plasma renin activity individuals taking antihypertensive medication Potassium Epidemiological as well as supplementation trials show that increased dietary potassium was related to decreases in blood pressure. Potassium promotes sodium excretion by the kidney. Calcium Epidemiological and laboratory studies support the relationship that calcium has a Beneficial effect on high blood pressure. Mechanism is unclear, there are several possible mechanisms. Magnesium Studies support an inverse relationship between magnesium and blood pressure. Mechanism is unclear. Both Mg and Ca can promote relaxation of the vascular smooth muscle. Alcohol 3 or more drinks/day associated with increased blood pressure. stimulates sympathetic nervous system, changes hormones (renin, angiotensin), and inhibits vascular relaxing substances (ex: NO). DASH diet Dietary Approach to Stop Hypertension Promotes diet rich in fruits, vegetables, and low-fat dairy products and low in fat. Limits red meat, fats and sugar-sweetened foods and beverages. Also encourages nuts, seeds, legumes. Provides: 3 g sodium 4500 mg potassium 8 – 10 servings of fruits and vegetables 2 – 3 servings of low-fat dairy products Current dietary guidelines for Americans recommend that adults in general should consume no more than 2,300 mg of sodium per day. At the same time, consume potassium-rich foods, such as fruits and vegetables. However, if you are in the following population groups, you should consume no more than 1,500 mg of sodium per day, and meet the potassium recommendation (4,700 mg/day) with food. You are 51 years of age or older. You are African American. You have high blood pressure. You have diabetes. You have chronic kidney disease. The 1,500 mg recommendation applies to about half of the U.S. population overall and the majority of adults. Nearly everyone benefits from reduced sodium consumption. Eating less sodium can help prevent, or control, high blood pressure. The challenge for public health agencies is to decrease Na consumption as well as increase K intake/ Phytochemicals: • Phytochemicals: phytos is the Greek work for plants. - can be any of the thousands of chemicals found in plants of dietary significance. - No single class of chemicals, but many classes diverse in structure. Example: a tomato contains over 10,000 different phytochemicals. • A single phytochemical is present in plants in multiple forms: a variety of glycosylated forms (bound to sugars) and the aglycone (non sugar) •orm. f Phytochemicals are not vitamins or minerals. They are not essential to humans and are therefore considered non-nutrient dietary components. • They are secondary metabolites in plants: not necessary for normal growth and reproduction, but lack will result in impairment of survivability. • In plants, they are defensive molecules. Classes of phytochemicals Polyphenols – contain a phenol ring. Sub classes: flavonoids, lignans, phenolic acids and tannins. Terpenes –composed of derivative of isoprene units (5-carbon chains) linked together. Includes monoterpenes, diterpines, Carotenoids (tetraterpenoids), saponins Organosulphides – contain sulfur. Includes dithiolthiones (isothiocyanate) and thiosulphonates (allium compounds). Indoles, glucosinolates – tend to have an amine group (nitrogen). Includes glucobrassicin, alliin & allicin. Polyphenols Flavonoids – red, blue, purple pigments Flavonols: Quercitin – red/yellow onion, tea, wine, apples, cranberries, buckwheat beans. Gingerol – ginger Kaempferol – strawberries, gooseberries, cranberries, peas, brassicates, chives Flavanones : Hesperidin – citrus fruit Nargenin – citrus fruit Flavones: Apigenin – chamomile, celery, parsley Flavan-3-ols: Epigallocatechin 3-gallate – green tea Theaflavin-3-gallate – black tea Anthocyanins (flavanals) and Anthocyanidins – red wine, many red, purple or blue fruits and vegetables Isoflavones: Genistein – soy, alfalfa, sprouts, red clover, chickpeas, peanuts, other legumes Daidzein – same as above Polyphenols continued Phenolic acids/Hydroxycinnamic acids Egallic acid – walnuts, strawberries, cranberries blackberries Gallic acid – tea, mango, strawberries, rhubarb, soy Salicylic acid – peppermint, licorice, peanut, wheat Tannic acid – tea, nettles, berries Capsaicin – chili peppers Caffeic acid – pear, basil, oregano, apple Chlorogenic acid – echinacea, strawberries, pineapple, coffee, sunflower, blueberries gnans (phytoestrogens) seeds (flax, sesame, pumpkin, sunflower, poppy), whole grains (rye, oats, barley), bran (wheat, oat, rye). Fruits (berries) and vegetables. Tyrosol esters Tyrosol – Hydroxytyrosol – Oleocanthal – Oleuopein - Olive oil Stilbenoids Resveratrol - grape skins and seeds, wine, nuts, peanuts Terpenes (isoprenoids) Carotenoids: Carotenes – orange pigment α-carotene – carrots, pumpkins, maize, tangerine, orange β-carotene – dark leafy greens and red, orange, yellow fruits and vegetables lycopene – tomatoes, grapefruit, watermelon, guava, apricots, carrots Xanthophylls – yellow pigment canthazanthin – paprika Zeaxanthin – wolfberry, spinach, kale, turnip greens, maize, eggs, red pepper Lutein – spinach, turnip green, romaine lettuce, eggs, red pepper, pumpkin Monoterpenes Limonene – oils of citrus, cherries, spearmint, dill, garlic, celery, maize, rosemary, ginger, basil Saponins – soybeans, beans, other legumes, maize alfalfa Lipids Phytosterols – almonds, cashews, peanuts, sesame seeds, sunflower seeds Organosulphides Dithiolthiones (isothiocyanates) Sulphoraphane – Brassicates Thiolsuphonates (allium compounds) allyl methyl trisulfide – garlic, onions, leeks, chives, shallots diallyl sulfide – garlic, onions leeks, chives shallots Indoles, glucosinolates indole-3-carbinol – cabbage, kale, Brussels sprouts, rutabaga, mustard greens sulforaphane – broccoli family Sinigren – broccoli family Allicin – garlic Alliin – garlic Allyl isothiocyanate – horseradish, wasabi, mustard Digestion and Absorption Phytochemicals can be found in food in various forms. A common form is as a conjugate. This can mean that it must be unconjugated before it can be absorbed. These phytochemicals are reconjugated in the enterocytes or the liver. Amounts in the body: dictated by: type of food, concentration, amount ingested Difficult to isolate and determine the true metabolic pathway. • In humans, phytochemicals are known to: function as antioxidants (able to donate electrons from reactive hydroxyl groups). flavonoids mimic estrogen (phytoestrogens) by binding to the estrogen receptor and inducing estrogen-responsive transcription. consumption has been strongly correlated with a decreased risk of development of chronic disease (cancer, cardiovascular disease, diabetes, inflammatory diseases). affect many biochemical and molecular pathways relevant to carcinogenesis. Proposed mechanisms by which dietary phytochemicals may prevent cancer Prevention of DNA binding. Induction of cell cycle arrest and induction of apoptosis, Antiangiogenesis, inhibition of cell adhesion and invasion Enzyme inhibition Inhibition of oncogene expression, Induction of tumor suppressor gene expression Antioxidant activity, enzyme induction and enhancing detoxification, enhancement of immune function and surveillance Figure 1. Mechanisms by Which Diet Potentially Influences Risk of Coronary Heart Disease. Decreases cholesterol levels Lowers blood pressure Decreases clotting Decreases inflammation Hu, F. B. et al. JAMA 2002;288:2569-2578 Copyright restrictions may apply. • Phytochemical content of dietary plants varies with soil and growing conditions. • Organic apples had 18.6% more polyphenols than fruit from non-organic sources (Weibel, 2000). • Organic wines had 26% higher polyphenols than non-organic wines (Leveite, 2000). • Organic vegetables had 20-120% higher antioxidant activity and 1.3-10-fold higher flavonoid content compared to the same vegetable grown nonorganically (Ren, 2001). • Lycopene is higher in ketchup produced from organic tomatoes (Chapman, 2004). • Designer or functional food: processed foods that are supplemented with food ingredients naturally rich in diseasepreventing substances. “,,,,ADA classifies all foods as functional at some physiological level (6) because they provide nutrients or other substances that furnish energy, sustain growth, or maintain/repair vital processes. However, functional foods move beyond necessity to provide additional health benefits that may reduce disease risk and/or promote optimal health. Functional foods include conventional foods, modified foods (ie, fortified, enriched, or enhanced), medical foods, and foods for special dietary use.” Position of the American Dietetic Association: Functional Foods. JADA 2009;109:735746. •Nutraceutical - specific chemical compounds in food, including vitamins and additives, that may aid in prevention. Figure 1. Functional food categories along with selected food examples. Functional food category Selected functional food examples Conventional foods (whole foods) Garlic Nuts Tomatoes Modified foods Fortified orange juice Iodized salt Enriched enriched breads Enhanced bottled water, Calcium-fortified FolateEnergy bars, snacks, yogurts, teas, and other functional foods formulated with bioactive components such as lutein, fish oils, ginkgo biloba, St John’s wort, Resveratrol • Resveratrol is a polyphenol found in 30 genera of plants. It is a stilbene, 3,5,4’-hydroxystilbene. • It is a phytoalexin, a defense molecule that kills pathogens. It is normally present in small amounts but is synthesized when the plant is attacked. • Human dietary sources include grapes and grape products, peanuts, berries, and rhubarb. • Grapes grown for wine are in a constant state of stress because of low moisture. Wine grapes are therefore particularly high in resveratrol. • Resveratrol is expressed in the skin of the grape. Thus, red wine contains higher concentrations of resveratrol than white wine, because when red wine is made it remains in contact with the grape skins for a longer period of time. • Depending on the variety and growing conditions, a bottle of wine can contain 10 mg of resveratrol. Sirtuins: • Are a family of highly conserved enzymes. • There are seven mammalian sirtuins, abbreviated SIRT 1-7. • Are NAD+-dependent and are inhibited by nicotinamide (one of the forms of niacin - Vit. B3). Sirtuins • Deacetylation of proteins such as nuclear histones changes the conformation of chromatin and affects gene transcription and expression. • As a result, SIRT activity modulates the expression of many genes, including those involved in cellular proliferation, senescence, apoptosis, and several transcription factors that govern metabolism, including fat storage and mobilization. • Increase the lifespan of simple organisms (yeast, C. elegans, fruit fly). • Are thought to be responsible for mediating some of the effects of fasting/calorie restriction. Mechanisms of resveratrol-induced anti-inflammatory activity in cardioprotection Figure 1. Mechanisms by Which Diet Potentially Influences Risk of Coronary Heart Disease. resveratrol resveratrol resveratrol resveratrol Hu, F. B. et al. JAMA 2002;288:2569-2578 Copyright restrictions may apply. Resveratrol and Neurodegenerative Disorders • Resveratrol has been shown, in vitro, to exhibit neuroprotective properties for Alzheimer’s Disease. Theory: Amyloid-Beta proteins are formed and have a cytotoxic effect in brain tissue. Resveratrol has proved to counteract Aβ toxicity through natural anitoxidant properties and/or by SIRT1 activation. Resveratrol and Metabolic Syndrome Epidemiological studies have linked light-to-moderate wine consumption with: • increased insulin sensitivity • increased HDL • Decreased fasting LDL cholesterol • 33% - 56% lower incidence of type II diabetes • decreased cardiovascular mortality Resveratrol as an Anticancer Molecule In vitro and in vivo studies have demonstrated the potential for resveratrol to: • inhibit cancer cell proliferation • reactivate apoptosis • allay the growth of cancer cells Challenge for all chronic disease use: Bioavailability - most resveratrol undergoes fast metabolization. An oral Dose of 25 mg results in only 5 ng/mL unconjugated blood level. To reach a dose of 25 mg, you need to drink 4 L of red wine. Resveratrol ...
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This note was uploaded on 11/25/2011 for the course NTR 365 taught by Professor Sweltzer during the Fall '11 term at University of Texas.

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11:22:11 - Review for Exam III (Part 1) - Minerals Major or...

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