Balanced Nutrition Coming to Fruition www.funFruit.com1987 Street Ave City, State60623, US.Balanced Nutrition Coming to Fruition www.funFruit.com1987 Street Ave City, State60623, US.NutritionNathalie WroyProfessor PuentesBSC 20864/20/13
Balanced Nutrition Coming to Fruition www.funFruit.com1987 Street Ave City, State60623, US.Nutrition Preface• Nutrition is the starting pointand basis for all human formand function from the timewhen we become a fertilizedegg. Nutrition plays a veryimportant part in cell division,growth, and development.Nutrition is the source of fuelthat provides the energy to dobiological work and to replaceworn out cells.Nutrition
• Weight is determined by one’s energybalance , or the balance in the bodybetween the amount of energy consumedand expended.• Body weight is stable when energy intakeor the energy from dietary sources such ascarbs, fats, & proteins = The energy outputor the use of calories to perform physicalactivity.• We gain weight when food intake exceedsoutput. And we lose weight when outputexceeds input• Body weight results from a combination ofheredity, and environmental influences• 30-50% of variation in human weight isdue to heredity and the rest is due to eatingand exercise habits.Body Weight and Energy Balance
• Appetite is the desire for foodor drink• Gut brain peptides arehormones that act as chemicalsignals from thegastrointestinal tract to thebrain• Gut brain peptides have aneffect on short term & longterm appetite and body weight• Short term peptides arehormones that work overperiods of min to hours makingone feeling hungry. BasicallyThese peptides make peoplebegin to eat a meal in whichafterwards you becomesatisfied.AppetiteAppetite Short term regulators of Appetite• Ghrelin – hunger from parietal cells of emptystomach. Stimulates hypothalamus release ofhuman growth hormone releasing hormone.Within an hour after eating, ghrelin secretionceases• Peptide YY (PPY)- enteroendocrine cells inileum and colon secreted in proportion tocalories consumed slows stomach emptying.The primary effect is to signal completesatisfaction and terminates eating.• Cholecystokinin (CCK) – Fromenteroendocrine cells of duodenum andjejunum. Has appetite-suppressing effect onbrain. Like (PPY) signals completesatisfaction & acts as signal to terminateeating
Long Term Regulators Of Appetite• Long term peptides regulate appetite,metabolic rate, and body weight overlong periods of time (effects lastweeks to years)• Leptin: Secreted by adipocytes ®ulate body fat. Leptin interacts withareas of the brain that control hungerand behavior and signals that the bodyhas had enough to eat. A small numberof people have genetic mutations inthe leptin gene, leading to a greaterdemand for food, resulting in obesity.• Insulin: Insulin is a peptide hormonesecreted by the pancreas in response toincreases in blood sugar, usuallyfollowing a meal. Has a weaker effecton appetite than leptin.
Appetite regulation• The Hypothalamus is an importantbrain center for appetite regulation .• Receptors for gut-brain peptides thatregulate release of: neuropeptide Y &melanocortin• Neuropeptide Y: Stimulates hungerstimulated by ghrelin and inhibited byPYY, leptin, and insulin.• Melanocortin : Inhibits eating stimulatedby leptin, and CCK inhibited by appetitestimulates called endocannabinoids.• Appetite is briefly satisfied by chewing,swallowing & stomach filling• Neurotransmitters stimulate desire fordifferent foods• norepinephrine – carbohydrates• galanin – fats• endorphins – protein
Calories• One calorie - amount of heat required to raisetemperature of 1 g of water 1 C• 1000 calories is a kilocalorie or Calorie• Fats contain about 9 kcal/g• Carbohydrates and proteins, about 4 kcal/g• sugar and alcohol are “empty” calories -- few nutrients• Substance used for fuel is oxidized primarily to makeATP which transfers energy other physiological processes
Nutrients• Nutrients: Any ingested chemicalused for growth, repair ormaintenance.• Macronutrients consumed in largeamounts• proteins, fats and carbohydrates• Micronutrients needed in smallamounts• Recommended daily allowances(RDA)• safe estimate of daily intake forstandard needs• Essential nutrients can not besynthesized• minerals, vitamins, 8 amino acids and1-3 fatty acids must be consumed inthe diet
Carbohydrates• Complex carbohydrates (starches) are found in bread, cereal, flour, pasta,nuts, and potatoes• Simple carbohydrates (sugars) are found in soft drinks, candy, fruit, and icecream• Glucose is the molecule ultimately used by body cells to make ATP• Neurons and RBCs rely almost entirely upon glucose to supply their energyneeds• Excess glucose is converted to glycogen or fat and stored• The minimum amount of carbohydrates needed to maintain adequateblood glucose levels is 100 grams per day• Starchy foods and milk have nutrients such as vitamins and minerals inaddition to complex carbohydrates• Refined carbohydrate foods (candy and soft drinks) provide energysources only and are referred to as “empty calories”
Carbohydrates (cont.)• Dietary sources: monosaccharides = glucose, galactoseand fructose• Liver converts galactose and fructose to glucose• Outside hepatic portal system, only blood sugar isglucose• Normal blood sugar concentration ranges 70 to 110mg/dL• Disaccharides = table sugar (sucrose), maltose, lactose• Polysaccharides = starch, glycogen and cellulose• Nearly all dietary carbohydrates come from plants
Dietary Fiber• Dietary Fiber: Fibrous material thatresists digestion• Fiber is important to diet average30 g/day• excess interferes with mineralabsorption - iron• Water-soluble fiber: (pectin) andother carbs found in oats, beans,peas, carrots, brown rice, and fruitslowers blood cholesterol levels.• Water-insoluble fiber: (cellulose,lignin) Has no effect on cholesterolit absorbs water in intestines,softens stool, gives it bulk, speedstransit time
LipidsLipids summary• Average adult male 15% fat;female 25% fat• Fat accounts for most of thebody’s stored energy• Fat is a better source than carbsbecause they are hydrophobicfat-soluble vitamins (A,D,E,K)absorbed with dietary fat• ingest less than 20 g/day risksdeficiencySources• The most abundant dietary lipids,triglycerides, are found in bothanimal and plant foodsSaturated fats• animal origin -- meat, egg yolks anddairy productsUnsaturated fats• found in nuts, seeds and mostvegetable oilsCholesterol• found in egg yolks, cream, shellfish,organ meats and other meats
Lipids (cont.)Lipids Function• Fatty deposits in adipose tissueprovide:• A protective cushion around bodyorgans• An insulating layer beneath theskin• An easy-to-store concentratedsource of energy• Prostaglandins: fatty acids withhormone like effects function in:• Smooth muscle contraction• Control of blood pressure• Inflammation• Cholesterol stabilizes membranesand is a precursor of bile salts andsteroid hormonesRequirements• Higher for infants and children thanfor adults• The American Heart Associationsuggests that:• Fats should represent less than 30%of one’s total caloric intake• Saturated fats should be limited to10% or less of one’s total fat intake• Daily cholesterol intake should notexceed 200 mg
Cholesterol & Lipoproteins• Lipoproteins: protein and phospholipid coat around a hydrophobic cholesterol andtriglyceride core.• Categorized into 4 groups by density: more protein = higher density• Chylomicrons: Form in absorptive cells of small intestine; main purpose is to carrytriglycerides and other fats to the liver and other tissues in the body contain morefat and less protein.• Very low-density (VLDLs): Molecules made up of mostly triglycerides, cholesteroland proteins. Very low density lipoproteins (VLDL), also known as the "very bad"cholesterol, carry cholesterol from the liver to organs and tissues in the body.• Low-density (LDLs): Carry cholesterol from the liver to tissues in the body. "badcholesterol"• High-density (HDLs): Carry excess cholesterol from the bodys tissues back to theliver. "good cholesterol"
Cholesterol• Desirable to maintain totalcholesterol concentration of < 200mg/dL• Most cholesterol has an internalcause or origin• Dietary restrictions lower bloodcholesterol levels• by 5% with restriction of dietarycholesterol• by 15 to 20% with restriction ofcertain saturated fats• Vigorous exercise lowers bloodcholesterol
Proteins• 12-15% of body mass• Mostly in skeletal musclesFunctions• muscle contraction• movement of body, cells, cell structures• Major component of all cell membranes (receptors, cell identity, pumps)• fibrous proteins (collagen, keratin)• structural• globular proteins (antibodies, myoglobin, enzymes)• functional• plasma proteins: blood osmolarity and viscosity• Buffer the pH of the body fluids and contribute to resting membranepotentials
Dietary Requirements• Average intake of proteins 44-60 g/day depending on weight, age, & gender.• Excessive protein can cause renal damage.• Out of the 20 essential amino acids adults can synthesize 12 organiccompounds; 8 of the 20 essential amino acids can not be synthesized andmust be obtained from dietary sources ; isoleucine, leucine, lysine,methionine, phenylalanine, threonine, tryptophan and valine• The other 10 amino acids are called inessential amino acids because thebody does not require them because they can synthesize on their own whenour diet doesn’t supply them.• Cells do not store surplus protein for later use• All-or-none rule; All amino acids needed must be present at the same timefor protein synthesis to occur• Complete proteins that meet all the body’s amino acid needs are found ineggs, milk, milk products, meat, and fish• Incomplete proteins lack one or more essential amino acids are found inlegumes, nuts, seeds, grains, and vegetables
Proteins (cont.)Dietary Sources• Complete proteins that meet allthe body’s amino acid needs arefound in eggs, milk, milk products,meat, and fish• Incomplete proteins are found inlegumes, nuts, seeds, grains, andvegetablesNitrogen Balance• Rate of nitrogen ingestion equalsrate of excretion• proteins are chief dietary sourceof nitrogen• Ingestion equals the rate ofexcretion.Positive nitrogen balance• occurs in children; they ingestmore than they excrete• promoted by growth and sexhormonesNegative nitrogen balance• body proteins being broken downfor fuel (muscle atrophy)• glucocorticoids promote proteincatabolism in states of stress
MineralsMinerals Summary• Minerals are inorganic elements thatplants extract from soil or water.• Minerals constitute about 4% of thebody’s mass with 3 quarters being calciumand phosphorous in the bones & teeth.• Phosphorus key component inphospholipids, ATP, CP, buffers, nucleicacids• Calcium, iron, magnesium and manganesefunction as cofactors for enzymes• Iron - essential for hemoglobin andmyoglobin• Chlorine - component of stomach acid(HCl)• Mineral salts function as electrolytes;govern function of nerve and muscle cells;regulate distribution of body waterDietary Sources• Vegetables, legumes, milk,eggs, fish and shellfish• Animal tissues contain largeamounts of salt• carnivores rarely lack salt intheir diets• herbivores often supplementby ingesting soils• Recommended sodium intakeis 1.1 g/day• Typical American dietcontains 4.5 g/day
Vitamins• Most vitamins must be obtained from diet.• Body synthesizes some vitamins from precursors called Provitamins• Vitamin A synthesized from carotene which is abundantly found insquash, and other yellow veggies and fruits. Vitamin D from Cholesterol.• vitamin K, pantothenic acid, biotin, folic acid• produced by intestinal bacteria• Water-soluble vitamins (C, B)• absorbed with water in small intestine; not stored• Fat-soluble vitamins (A, D, E, K) absorbed with dietary lipids; stored
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