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Altered Nutrition.docx

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Dalhousie University
NURS 2090
Heather Helpard

Altered Nutrition Nutrition: Ingestion and utilization of nutrients for energy *nutrition is as (if not more) important as pharmaceuticals for our health and healing. Essential Nutrients: must be consumed regularly in diet as body is unable to synthesis quantities needed Metabolism allows chemical reactions that: 1. Produce heat and maintain body temp 2. Conduct neuronal impulses 3. Contract muscle Video:  Hippocrates said let food be thy medicine; however, we have changed the way we look at health. We no longer look at optimal nutrition, but rather medications. Dr’s nowadays get very little education on nutrition.  There is a lot of money to be made, by having ppl sick.  You are what you eat! Food does matter.  How old is your food? By the time it gets to you, it has travelled 2000 km. It is at least 5 days old. How much nutritional value does it have? If you are lucky, you are getting at least 40% of what you need.  Foods are being genetically modified (which we know nothing about), the fertilizer nowadays has (P, K, N); however it actually needs 52 other types … which are missing.  Plants become diseased, less resistant to pest.  There is business in selling pesticides to ‘fix the problem’  On top of having the food grow deficient in nutrients, we then cook it. Which then looses more of the nutritional value (because of decreased enzymes, remember heat denatures proteins/enzymes)  In response to COOKED food, our body launches an inflammatory process, digestive leukocytosis (generating WBC activity). It recognizes the food as a toxin.  Study done that showed if you eat 51% of your diet in COOKED food, your body will react in the same way, as if your body was being invaded by a foreign organism.  If 51% of your food is RAW, you will have no leukocytosis (no WBC’s activated), which means you will not overburden your immune system.  Nutrient deficiency is the #1 cause of illness and disease Water: *adults can survive only 10 days w/out water (children only 5 days), metabolically active cells have the most devastation (i.e mucles b/c they have the most water) 1. Solvent promoting availability of 4. Serves as a lubricant solutes to cell 5. Regulates body temp 2. Promotes/maintains fluid balance 6. Foundation for metabolic reactions 3. Transport medium for 7. Contributes to structure of cells nutrients/waste Macronutrients: 1. Protein (proteins → amino acids, which are absorbed. Amino acids synthesize proteins)  20 different kinds in the body (9 are essential)  Required to build/maintain body tissue (muscle, bone matrix and connective tissue)  Composes blood, cell membranes, immune factors, enzymes and hormones  Transports substances across membrane  Combines with other substances to form new substances (protein + nucleic acid = DNA/RNA, protein + carbs = glycoproteins, protein + lipids = lipoproteins, proteins + metals = hemoglobin)  Public has a fear in protein deficiency. But it’s easy to eat too much of it, will burn it as a fuel (but it is much less efficient than carbohydrates/fats, and does not burn clean. It will leave ashes, amino acid residue that must be filtered by the liver/kidneys).  Too much protein will cause the liver and kidneys to become overrun with residue (this is why in kidney and liver failure patients are often on a protein-restricted diet, but not just end stages!!! May help prevent/delay end stage kidney failure.  Reduce animal proteins. Try to substitute veggie proteins/soy. Evidence for soy is strong (but not soy substitutes/supplements). Offers protection against cancer, especially for prostate and breast cancers. 2. Carbohydrates  Glucose is absorbed across the intestinal wall and transported to the liver  50% is used for oxidation of stored as glycogen and the other 50% exits the liver and is circulated throughout the body to be used by cells for energy  Main role of carbs is to provide energy (but they are not considered essential nutrients, because the body can make them from other sources; however, the other ways are less efficient)  The brain is the largest consumer of glucose but this can be provided by fats and proteins (AAs from protein and glycerol from triglycerides can be converted into glucose)*this is not an efficient but adaptive process  Carbs (complex rather than sugar) should compose the largest part of the diet, because complex have vitamins and minerals and is broken down slower. Categories: 1. Monosaccharides: glucose & fructose 2. disaccharides & oligosaccharides: glucose & fructose 3. polysaccharides: starch & fiber Fiber (indigestible carbs)  Reduces serum cholesterol levels  Binds to bile acids (cholesterols) to prevent absorption  Influences gastric motility  It binds to bile salts to prevent obstructions in the bowel  It decreases colon cancer and cholesterol, We should be consuming 35mg/day Video on Carbs:  Plants make carbohydrates by binding energy of sunlight, with CO2 + water, to create glucose (energy currency of all life).  Misinformation of carbs in our culture. Simple/complex, told to eat less simple and more complex. Glycemic index/load is actually more important to look at it. Culture is slow to accept this new outlook. More difficult to understand. Less familiar.  Glycemic index: 1. Puffed rice cake is at the top of the scale b/c infinite surface area to digest, 2. Table sugar is low because body has little ability to metabolize fructose. 3. Oatmeal cookie has less glycemic value than oatmeal b/c it has fat, which slows gastric emptying, 4. Acid added to food lowered the glycemic load because it slows gastric emptying.  Forms of glycemic index determined by chemical, mechanical nature.  Glycemic index vs load – depending on the type of carb we eat, this will cause a spike in blood sugar at different rates (fat and acid will slow this down)  Grains have sustained human life. But it’s what we have done with grains that is the problem. Almost everything is made with grain. Also high sugar. Its everywhere. Combination of high sugar, and carbohydrates (flours), is a huge glycemic load, which creates obesity, insulin resistance, metabolic syndromes. Glycemic load: more useful, is a number that estimates how much the food will raise a person's blood glucose level after eating. Glycemic index: If you take this into account, you will tell ppl not to eat carrots/beats because of the high index, but that is not sound nutritional advice. Content is important. May have to eat a large quantity to have a negative effect. Iis a scale that ranks carbohydrate-rich foods by how much they raise blood glucose levels compared to a standard food. The standard food is glucose or white bread. 3. Lipids (insoluble in water) **it’s the overabundance of sugars- NOT FATS in obesity prob  Provide a rich source of energy, stored in adipose (a small amount can be stored in other parts, like the liver, but too much will impair its function)  Structural fat is not accessed for energy. It is used structure/ protection to body organs/nerves. Found in brain, liver, kidney, heart, etc (essential for survival) Functions: 1. Supports digestion (decreases gastric motility & secretions) 2. Stimulates pancreatic and bile secretion 3. Facilitates digestion, absorption and transport of fat soluble vitamins 4. Supports brain, CNS and cell membrane function (Omega 3, and phospholipids) 5. Hormones Omega 3 (linolic acids)  Obtained from fish and plant oil  Essential fatty acid  Reduces disease states (heart disease) by: 1. Reducing fibrinogen and clotting proteins (reduces clots) 2. Stimulating endothelial cells to produce substances that promotes vascular relaxation  Omega 3 & 6 – our diet is overabundant in Omega 6 and this impacts our metabolism of Omega 3 (they must be available in a balanced ratio). This is due, in part, to grain fed rather than grass fed livestock. It is also due to the addition of soybean oil as a filler in cheap foods Categories: 1. Simple Lipids (Fats): fatty acids and glycerol (triglycerides) 1. Saturated fatty acids  No double bonds, solid at room temp  Elevate blood cholesterol levels, Found in animals sources 2. Unsaturated fatty acids (these are more healthy and should be consumed)  One or more double bonds, Liquid at room temp  Do not elevate blood cholesterol levels, Found in plant sources 2. Compound Lipids (Lipoids): phospholipids, lipoproteins, glycolipids 3. Sterols: cholesterol, bile salts Micronutrients: 1. Vitamins (organic substances)  The body is unable to manufacture these and therefore must consume them  Are a part of enzyme systems that release energy from macronutrients  They help develop genetic materials, RBCs, hormones, collagen, NS tissues  there is controversy regarding their toxicity ie. Vit C therapy and cancer Solubility Categories: 1. Fat Soluble: Vit A,D,E,K 2. Water Soluble: Vit C and all Bs Metabolic categories: 1. Stabilize membranes 2. Hydrogen and electron donors/acceptors 3. Hormones 4. Coenzymes 2. Minerals (Inorganic Substances that regulate cellular processes)  Constitute bone, hemoglobin, enzymes, hormones and chemical mediators  Charged minerals mediate impulse conduction in NS (ions)  Maintain H2O balance, acid-base balance and osmotic pressure  Critical for muscle contraction and form the structure of bones/teeth Categories: 1. Macrominerals: electrolytes, primarily ions in charged states (Na, K, Ca, P, Mg, S) 2. Mircominerals: These are found bound to proteins. Rather than in an ionic state. Often referred to as trace metals. These metals act on enzymes and hormones to elicit responses and interact with DNA (Fe, Zn, F, Cu). **affect whole body. 3. Ultratrace minerals: minute responses required (I, Se, M, etc.) Nutritional Intake Requirements:  Recommended Daily Allowance (RDA): to minimize health effects that occur with under/overnutrition  Depends on age, gender, activity level, weight, pregnancy, lactation  Carbs – 50-60% RDA  Fats – 30% or less RDA  Protein – 10-20% RDA Intake:  Balance between intake and expenditure  Intake is regulated by satiety, hunger, emotional/physical health  Hunger and satiety are regulated by the hypothalamus (feedback loop): 1. Low blood glucose level/lack of food = hunger 2. Presence of food activates stretch receptors and insulin secretion= reduce diet 3. Fat stimulates cholecystokinin (GI hormone) = satiety 4. Increased fat stores activate leptin release (hormone) = suppressed appetite/ increased energy expenditure, increased metabolism Storage: 1. Adipocytes: store lipids (key energy sources when needed) 2. Liver: stores vitamins and minerals, and glycogen (A, B12, D, E, K, Fe, Cu)  when glycogen stores are exhausted, the liver converts amino acids and glycerol to glucose Digestion: Food is broken down mechanically and chemically in the gastrointestinal tract and converted into absorbable components Mechanical Breakdown: physically breaking down and moving substances through the digestive tract (chewing & peristalsis: mechanical churning of food in stomach) Chemical Breakdown: using digestive enzymes + bile to convert ingested substances into absorbable components (involves accessory organs such as salivatory glands, pancreas and liver) 1. Begins in the mouth (salivary amylase) 2. In the stomach, food is mixed with HCl, pepsin, other digestive enzymes: 1. Mucus cells: secrete alkaline mucus and protect epithelium 2. Parietal cells: secretes HCl (which activates pepsinogen and destroys pathogens), and intrinsic factor (which is needed for absorption of B12 3. Chief cells: secrete pepsin (which is critical for protein digestion) 4. G cells: secrets gastrin (hormone responsible for controlling acid secretion and stimulating gastric motility) 3. Final stage, small intestine in the intestinal villi (brush border), which have columnar/mucus secreting epithelial cells. They are capable of absorption and secretion.  Intestinal folds allow slower passage, to increase absorption  As they move through the small intestine, they are met with: 1. bile salts from the liver (fat digestion) 2. Bicarb from pancreas (to neutralize acid) 3. Enzymes from pancreas (to digest fats, proteins, carbs) Motility: moving of food from mouth to anus, mechanically mixing food to break it into smaller units  Motility refers to mixing and moving of luminal contents. Two important motility patterns are peristalsis (observed in esophagus, stomach and intestine) and segmentation (occurs in intestines). Amylase: the first enzyme, encountered in the saliva, breaks down carbs Esophagus: first peristaltic action, takes 6 seconds to reach the stomach Stomach: gastric juice (pepsin) is the 2 enzyme, breaks down protein, within 2-3hrs for digestion Small intestine: amylase, protease, lipase (fat digestion) and bile salts, villi help to absorb blood, 1. carbs are converted into glucose in the small intestine and stored in the liver 2. Fatty acids and glycerol are emulsified using bile (too much creates a gall stone) Regulation of Digestion:  (except chewing, swallowing and defecation) digestion is regulated through hormone feedback mechanisms and the autonomic NS  Sympathetic and parasympathetic NS both act on the walls of the GI tract to promote digestion Layers of the GI Tract: 1. Inner mucosa: lines the lumen (in direct contact with nutrients)  epithelial cells secrete, absorb and produce hormones  provides immune protection (Peyer’s patches and lymphocytes) 2. Submucosa: connective tissue layer  contains blood and lymphatic vessels and submucosa plexus (nerve branches that provides local and autonomic NS stimuli to the GI tract) 3. Muscularis: composed of 2 thick layers of smooth muscle  promotes mechanical movement of nutrients through lumen  contains mysentaric plexus for neuronal stimulation 4. Serosa: outer covering of GI tract  connected by mesentery which supports digestive tract and provides pathway for vascular and neuronal stimulation Overall Goals of Digestion: 1. Convert carbs into monosaccharides 2. Convert proteins into AAs 3. Convert fatty acids into glycerol 4. Unleash vitamins & minerals from macronutrients 5. Separate H2O from nutrients to promote H2O absorption Hormones in GI tract 1. stimulate gastric emptying: Gastrin & Motilin a. Gastrin: stimulates gastric glands to secrete pepsinogen (proenzyme that converts to pepsin) and hydrochloric acid 2. inhibit gastric emptying: Secretin a. Secretin: trigger the release of bicarbonate from the pancreas and bile from the liver b. Gastric Inhibitory Peptide: decreases stomach churning c. Cholecystokinin: (duodenum) stimulates the release of digestive enzymes in the pancreas and emptying of bile from the gall bladder Absorption: Moving nutrients from digestive tract to the circulation in order to be used by cells  Process varies depending upon nutrient  Small intestine: ideal for nutrient absorption b/c of surface area, and absorptive fluid layer along brush border. Lacteals lymphatic channels in each villi are critical to absorb fat molecules.  Large intestine & stomach: water  Skin: vitamin D  Liver: receives nutrients that were in the lumen, where they are metabolized, converted and synthesized to other nutrients. Stored for later 1. Carbohydrates- Glucose & Fructose:  Largest proportion of nutrients absorbed within the digestive tract  Monosaccharides (glucose and fructose) are rarely consumed in a typical diet  Complex carbs (sucrose, lactose, starches) must be degraded by enzymes and reduced to monosaccharides for absorption Carbohydrate Absorption: 1. Pancreatic amylase acts on dietary carbs to begin reduction into simple sugars 2. Final enzymatic digestion liberates complex carbs into monosaccharides using brush border enzymes *small intestine. (sucrase, lactase, and maltase) 3. Glucose (and galactose) requires cotransport of NA to be absorbed into the lumen of the small intestine through active transport Active Transport: many nutrients require energy dependant transport pumps to be absorbed across mucosa (ie. Glucose, galactose, Ca, Fe, aa, K, fatty acids, Mg) * for glucose, two sodium ions bind to the transporter. A change in the transporter occurs and the glucose can bind to the transporter so it can move into the cell. Glucose then diffuses down its concentration gradient into capilliaries within the small intestine. Passive Transport: random migration of nutrients across the mucosa (from high to low concentration or pressure) (vitamins, water – which pass unchanged) 1. Simple Passive Transport: nutrients move through or between channels (ie. Fructose) 2. Facilitated Passive Transport: carrier protein molecules are used to move nutrients across the GI mucosa 2. Proteins (amino acids)  Use proteolytic enzymes (to degrade dietary proteins into small pept
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