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The Gastrointestinal System T-Talk 3.1 By Jennifer Turley and Joan Thompson © 2013 Cengage Presentation Overview • The Process • The Organs • Enzymes & Hormones • After digestion: – absorption – transportation – utilization – excretion What is Digestion? • The breaking down of food • Big food parts into smaller ones (mechanical) – Involves muscles and nerves • Big nutrients into smaller ones (chemical) – Involves acid, enzymes, and hormones What is a Hormone? • Chemicals produced by cells (typically in an endocrine gland), and are secreted, then affect the behavior of cells at distal sites in the body. • Examples of hormones in digestion include: cholecystokinin and secretin. What is an Enzyme? • Protein that catalyze metabolic reactions, and are necessary for most biochemical reactions to occur. • Digestive enzymes specifically break down food substances. • Examples include: amylase for carbohydrate, protease for protein, and lipase for Lipids/Fat. The journey begins in the mouth with • Mechanical digestion: chewing (mastication) • Chemical digestion: saliva (lubrication) and amylase (breaks down digestible carbohydrate) food becomes bolus 1 The Stomach The Esophagus • Peristalsis begins. • Peristalsis is: a muscular wave action that occurs throughout the intestinal tract. It is controlled by the central nervous system and facilitates excretion by propelling food stuff through the body. The Small Intestine • Duodenum • Jejunum • Ileum Villi & Microvilli The Accessory Organs • Is a muscular organ & storage reservoir. • Mechanically digests food by mixing & churning. • Chemically digests food with acid and some enzymes (pepsin). • Here, the bolus becomes chyme. Signaling the accessory organs • Why? – For assistance in digesting the food stuff. • How? – By hormones. – The cells of the intestinal wall produce the hormones cholecystokinin and secretin which enter the blood stream and signal the accessory organs. The Function of Bile Emulsifier • The Liver – Makes bile • The Gallbladder – Stores bile • The Pancreas – Makes enzymes for the chemical digestion of carbohydrates, proteins, and fats – Makes sodium bicarbonate to neutralize stomach acid 2 Mechanisms of Absorption Absorption • Passive (Simple) Diffusion (Transport): Nutrients like water & lipid byproducts pass freely across membranes via a concentration gradient. • Facilitated Diffusion (Transport): Nutrients like water soluble vitamins diffuse across membranes using a specific/selective transport proteins. • Active Transport: Nutrients like glucose & amino acids move across membranes against a concentration gradient using a specific/selective transport protein & energy/ATP. • • • • Sites of Absorption Transportation of Nutrients Duodenum: many nutrients Jejunum: many nutrients Ileum: only selected nutrients Colon (large Intestine): water • Blood vessels: water soluble nutrients Cellular Storage • Short term • Intermediate • Long term • Lymphatic vessels: fat soluble nutrients Metabolic Usage • Catabolic reactions: Breaking down (things get smaller). Involve hydrolysis reactions. Are degrading or destructive in nature. • Anabolic reactions: Building up (things get bigger). Involve condensation reactions. Are synthesizing or constructive in nature. • Homeostasis: The balance of catabolic and anabolic reactions in a person so a relatively stable internal environment or equilibrium is achieved. 3 Metabolic Examples Excretion • What action does the enzyme lipase have on triglycerides: Anabolic, catabolic or neither? • What action does bile have on triglycerides: • The Kidney: water & • What action does the hormone secretin have on the liver: Anabolic, catabolic or neither? • The Lung: carbon dioxide Anabolic, catabolic or neither? water soluble waste. • The Skin: water & water soluble waste. & water. • The Colon (Large Intestine): Water is removed & waste (bacteria, fiber, sloughed cells, & undigested food) is compacted. Summary • Chemical & mechanical digestion. • Enzymes vs hormones. • The gastrointestinal tract, organs, and accessory organs. • Nutrient absorption & transportation. • Assimilation of nutrients, storage, & metabolic usage. • Excretion of waste. References for this presentation are the same as those for this topic found in module 3 of the textbook 4 Proteins: From Foods to Cells in the Body T-Talk 3.2 By Jennifer Turley and Joan Thompson © 2013 Cengage Protein Denaturation! • Causes the protein to change shape or conformation. • The protein and the amino acids are still intact. • Can be caused by heat, alkali or acid treatments, or metals. • Is required before the protein can be digested. Protein Denaturation to Digestion Presentation Overview • • • • • • • Denaturation vs. Digestion Synthesis Character & Types Functions Quality Needs (Recommended Intake) Deficiency vs. Excess Protein Digestion • The protein strand is broken and the amino acids are released. • Occurs by the protease enzymes secreted by the pancreas and GI mucosal cells. • Amino acids are absorbed, transported to cells and then used to build proteins. Protein Synthesis • We eat protein, denature & digest the protein, absorb & transport the amino acids to the cells, then within each cell, protein is made (synthesized) according to the DNA. • Protein is synthesized in a process of converting DNA to RNA & then protein. 1 The Gene Encodes Proteins Protein Character • Protein Character is determined by: – How the 20 amino acids are combined together (the sequence). – The polypeptide strand folding & interacting. Low & high quality dietary proteins support these Protein Functions 1. 2. 3. 4. 5. 6. 7. 8. Growth & tissue maintenance (replace, repair & possibly add LBM). Enzymes (catalysts). Antibodies, complement proteins, circulating components of immunity. Fluid & electrolyte balance (free proteins). Acid - base balance (H donors & acceptors). Energy (4 Cals/gm, requires N removal). Protein hormones like insulin & glucagon, secretin & cholecystokinin. Transportation of nutrients (lipoproteins). Protein Synthesis inside the Cell Types of Protein! Fibrous • Uniform in structure. • Either exclusively helical or sheet formation. • Examples are the proteins found in hair, muscle fibers & finger nails. Globular • Have variation in structure. • Are part helical, part sheet, part random, or completely random. • Examples of globular proteins include blood, mucous, milk protein and egg white. Adult Protein Need (DRI & AMDR) Sample Calculations • Eric weighs 90 Kg and ate 88 g of protein and 3000 Calories in one day. • What is his DRI for protein? – 90 Kg x 0.8 gm/Kg = 72 gm protein • What % of his DRI for protein did he consume? – 88 gm ÷ 72 gm x 100 = 122% • What % of Calories in his diet came from protein? – 88 g protein x 4 Cal/gm = 352 Cals from protein – 352 Cals ÷ 3000 Cals x 100 = 11.7% 2 Protein Excess" Protein Deficiency • Protein deficiency is called Kwashiorkor. The individual has peripheral edema and may not look undernourished. • Protein-Energy deficiency is called Marasmus. The individual looks undernourished (skin & bones, starvation). • Both conditions occur primarily in 3rd world countries. • In the U.S. individuals who are on starvation diets, poor, abused, or in hypermetabolic states can experience Kwashiorkor or Marasmus. • Is most common in athletes & fad dieters. • Increases risk of: Kwashiorkor Marasmus Body Builders Body Builders sample diet • Meal 1: Cooked cereal, 12 egg whites, banana, 1 piece whole wheat toast, coffee, water, vitamin/mineral & amino acid supplements. • Meal 2 (Pre-workout): Protein powder, carbohydrate powder, amino acids. • Meal 3 (Post-workout): 8 oz poultry, rice, sweet potato, corn, non-starchy vegetable, amino acids. • Meal 4: 7 oz fish, rice, salad, potato, water, amino acids. • Meal 5: 8 oz beef, potato, mixed vegetable, water, amino acids. • Meal 6: Cooked cereal, 10 egg whites, amino acids. What it takes to gain muscle 7 gm/oz 7 gm/oz 7 gm/white • One pound muscle is: 75% water, 20% protein, 5% other material like fat, glycogen, minerals, enzymes. • One pound muscle equals 105 grams protein. • To gain one pound muscle in 2 weeks an athlete would need an extra 7-8 g protein/day intake. – 1 oz meat, 1 cup milk, 3 slices bread. 7 gm/oz 3 gm/0.5 c 2 gm/0.5 c 4 gm/0.5 c – Dehydration. – Liver & spleen enlargement. – Accelerated kidney aging. – Metabolic acidosis (with low carbohydrate intake) – Vitamin B6 deficiency, Ca & Zn loss. – Heart disease & cancer. sample diet analysis results • 5500 Calories • 36% Calories from protein, 49% carbohydrate, 15% fat • Inadequate in vitamin E (83% DRI) and Calcium (75% DRI) Summary • Dietary protein is denatured then digested. • The amino acids from dietary intake are used by cells to make proteins by converting DNA to RNA to protein. • Protein character is determined by amino acid sequence. 3 gm/slice 3 gm/0.5 c 3 Summary • Proteins types: fibrous & globular. • Proteins have many functions in the body. • Protein deficiency is called kwashiorkor. • Protein excess can led to negative health affects. References for this presentation are the same as those for this topic found in module 3 of the textbook 4 Photosynthesis and Fiber T-Talk 3.3 By Jennifer Turley and Joan Thompson © 2013 Cengage Photosynthesis • The process by which plants make carbohydrate structures. • Photosynthesis requires chlorophyll. • CO2 + H20 + sunlight = carbohydrate in plants. Presentation Overview • Photosynthesis • Carbohydrate structures: sugar, starch, fiber • Fiber categories & recommends • Fiber benefits & actions • Negative effects of too much fiber • Food sources Fiber Content in Foods • Dietary Fiber: The residue after “in vivo” treatment. Animal tested. • sugars • starch • fiber Fiber Content in Foods • Functional Fiber: Indigestible carbohydrate isolated from natural sources or synthetic indigestible carbohydrate. • Has beneficial physiological effects in humans. • An example of indigestible carbohydrate isolated from a natural source is cellulose gel added to a processed food. Fiber Content in Foods • Total Fiber: • Is the combination of dietary & functional fiber in food. • Is reflected as the fiber content value on food package labels in the Nutrition Facts panel. 1 Categories of Fiber: Categories of Fiber: Insoluble Soluble Solubility Fiber Sources Food Sources Softens & Pectins Gels in Gums water. Does Mucilages attract water Fruits (like apple pectin), vegetable, legumes, and oats Fiber Recommendations • The DRI for total fiber intake: • Adult ♂ is 38 grams. Adult ♀ is 25 grams. • Personalized DRI is 1.4 grams total fiber per 100 Calories consumed. • Example: A person eating 4200 Calories in 1 day should consume 59 grams of fiber. Fiber Food Sources Solubility Fiber Sources Does not soften Cellulose Hemior gel in water. cellulose Does attract Lignins water Food Sources Whole grain foods, Celery strings Apple peels High Fiber Intake & Foods • High fiber intake is well over 2 grams/100 Calories consumed. • High fiber foods provide > 2 gm fiber/serving. • High fiber foods are easy to assess on the food package label by comparing the grams of fiber with reference to the Calories provided/serving. Fiber in Foods Most American under consume these types of foods and thus fiber. The average American fiber intake is 11-13 gm/day. 2 Food Sources & Amounts of Fiber Food Very High High Good Low Group >4gm 2-4gm 1-2gm ≤1gm ½ C Bran Flakes 1 C Shredded whole wheat or whole multigrain cereal 1C Oatmeal or puffed brown rice cereal 1 Slice Whole Wheat Bread 1 Slice Rye Bread ½ C Brown or Wild Rice 1 Corn Tortilla 1 C Cornflakes ½ C White Rice! ½ C Pasta Grains Food Sources & Amounts of Fiber Food Very High High Good Low Group >4gm 2-4gm 1-2gm <1gm N/A 1 Apple, Banana Orange, Peach, 1 C Berries 2 Prunes ½C 1 C Fruit Watermelon, Juice Honeydew melon, Cantaloupe Fruit Food Sources & Amounts of Fiber Food Very High High Good Low Group >4gm 2-4gm 1-2gm <1gm ½C Broccoli, Cauliflower, Corn, Beans, Cabbage 1oz Nuts & Seeds ½C Carrots, Green pepper, Celery, Onion, Lettuce 1 C Some Vegetable Juices ½C Legumes Vegetable (dried beans) Benefits-Actions of Fiber: Bulk • Increases the volume of food in the diet without adding Calories, thus it decreases the caloric density of the food. • Bulks the stool volume. • Both soluble & insoluble fiber provide these benefits. Benefits-Actions of Fiber: Benefits-Actions of Fiber: Stool Softener Decreases transit time • Complex carbohydrate chemical structures are hydrophillic (binds water or attracts water) creating a softer stool that is easier to move along the G.I. tract. • Relieves constipation, hemorrhoids, & diverticulosis. • Both soluble & insoluble fiber provide these benefits. • Food, the bolus, chyme and feces move through the GI tract faster, thus the transit time is reduced. • Decreases time in the colon. • Reduces exposure time to potential carcinogens thus reduces colon cancer. • Both soluble & insoluble fiber provide these benefits. 3 Benefits-Actions of Fiber: Benefits-Actions of Fiber: Improves GI tract muscle tone Heart-Health • The larger volume of bulk and the softer mass moving through the “tube” allows the GI tract muscles to exercise efficiently. • Both soluble & insoluble fiber provide this benefit. • Reduces heart disease risk by binding cholesterol-rich bile in the GI tract. • Normally, bile is reabsorbed. • Bile binds tightly to soluble fiber & cannot be reabsorb. • Thus, a large source of cholesterol can be excreted in the feces. • Soluble fiber provides this benefit. Benefits-Actions of Fiber: Benefits-Actions of Fiber: Heart-Health Increases gastric emptying time. Gallbladder stores Bile Liver Makes Bile from Cholesterol Released Bile emulsifies fat in G.I. tract Bile is reabsorbed In absence of soluble fiber Bile is reabsorbed, little is excreted In presence of soluble fiber is excreted • It takes a longer time for the chyme to leave the stomach. • The rate of glucose absorption is slowed. • This is beneficial with diabetes & reactive hypoglycemia. • Soluble fiber provides this benefit. Negative Effects of too Much Fiber Whole Grain Processing • Causes gas & bloating (due to decomposition of • Wheat kernels are refined by removing the husk, bran, & germ. • The endosperm (containing mostly starch & protein) remains. • Iron, thiamin, riboflavin, niacin, folate, vitamin B6, magnesium, zinc, & fiber are lost. fiber by gastrointestinal microbes) • • • • • Too large & frequent bowel movements Binds positively charged minerals Binds beta-carotene Decreases caloric value Can cause GI tract blockages without adequate water intake • Too much soluble or insoluble fiber can cause negative effects 4 Whole Grain Processing • Some nutrients are added back into refined grain products as a result of the Enrichment act of 1942. Processing a Wheat Kernel • Added: iron, thiamin, riboflavin, niacin, folate • Not Added: vitamin B6, magnesium, zinc, fiber % Nutrients in whole grain, enriched white & unenriched white breads Fiber Summary • Plants make carbohydrates via photosynthesis. • Fiber is non-caloric. • Categories are soluble & insoluble. • Total fiber = functional & dietary fiber. • The DRI is 1.4 gm/100 Calories eaten. • There are health benefits for adequate fiber intake. • There are negative effects from too much fiber. • Whole foods provide the best source of fiber and nutrients. References for this presentation are the same as those for this topic found in module 3 of the textbook 5 1/20/12 Carbohydrate Storage and Disorders T-Talk 3.4 By Jennifer Turley and Joan Thompson Presentation Overview • • • • STORAGE DISORDERS Blood Sugar (glucose) • Lactose Intolerance & Starch vs. Glycogen Lactose Mal-digestion Glycogen in detail • Hypoglycemia Blood sugar regulation • Diabetes • Insulin & Glucagon © 2013 Cengage What is Glucose Used for? • Immediate carbohydrate energy &/or glycogen storage (Liver & Muscle). • Brain, central nervous system (CNS), & red blood cell (RBC) function (liver glycogen). – Requires a minimum of 100-150 grams carbohydrate day (continuous). • Muscle functioning (muscle glycogen). • Fat synthesis (excess energy intake). Where is Glycogen Stored? • The Liver (100 grams; 400 Calories). – Is used for blood sugar (glucose) regulation. • The Muscle (1-4 grams/100 grams of muscle). – The level increases with high carbohydrate diets & exercise. – Is used for the working muscle. What is Glycogen? • The storage form of glucose, “animal starch”. • Made from dietary carbohydrate sources. – All carbohydrate is converted to glucose then stored as glycogen or used immediately. Diets should be planned to meet the 45-65% of Calories AMDR & minimally the DRI for carbohydrate (130 gm/day for adults). How Does the Body Regulate Blood Sugar? • By hormones that are produced in the pancreas. • The hormones effect the liver & muscle cells. – Insulin: decreases blood sugar levels. – Glucagon: increases blood sugar level. 1 1/20/12 Blood Sugar Regulation Blood Sugar Regulation Carbohydrate Related Disorders Lactose Intolerance • Lactose Intolerance & Lactose Mal-digestion • Hypoglycemia • Diabetes Lactose Intolerance Physiology: • Lactase deficiency (completely missing in “intolerance” while low activity/levels in “mal-digestion”) is strongly tied to evolution with several gene mutations identified. • Symptoms: Gas, bloating, cramps, diarrhea. Dairy Products and Lactose Intolerance • Use a product like lactaid • Consume yogurt with live cultures • Consume aged cheese OR • Avoid dairy products 2 1/20/12 Allergy vs. Intolerance • Lactose intolerance & mal-digestion are due to an inability to digest milk sugar (lactose) not an allergic reaction to milk protein (casein). • An allergy elicits an immune reaction & involves antigens & antibodies. Antibody and Allergen in an Allergic Immune Response – Antibody: Protein structures produced by immune cells that inactivate antigens (allergens). – Antigen (allergen): Foreign protein substances that elicit an immune reaction. • Allergic responses cause the formation of mucous in the respiratory tract, GI distress &/or hives. Hypoglycemia low blood sugar • Reactive: Blood sugar levels drop after eating sugar. – Too much insulin is secreted in response to sugar consumption. Hyperinsulinemia. • Spontaneous: Liver stores of glycogen are depleted, the ability to maintain blood sugar is diminished. – Happens to everyone in between meals or when food has not been consumed. 4-6 hours during the day, 10-12 hours with sleep. • Drug Induced: Low blood sugar from a drug reaction. – Improper insulin or oral hypoglycemic drug use with diabetes. – Anti-inflammatory and thyroid medications are known to cause hypoglycemia. Type 1 Less common • • • • ~5% of cases Juvenile onset Is more difficult to control Insulin administration is essential in the control of blood sugar (Insulin-dependent diabetes) • Is due to a genetic and/or viral factor causing auto immunity directed against the pancreatic beta cells Diabetes A chronic disease • Is characterized by hyperglycemia (high blood sugar). • Affects >20 million Americans, many unaware. • Increases heart disease, stroke, kidney disease, retinopathy, and neuropathy. • Decreases life expectancy. • Occurs as type 1 or type 2 diabetes. Physiology of Type 1 Diabetes Blood Stream 1. Antibodies attack the insulin producing cells of the pancreas. 2. No insulin is made. 3. Blood glucose/sugar levels are high. 4. Liver & muscle cells cannot take up glucose because there is no insulin to bind the cell receptor. 3 1/20/12 Type 2 Physiology of Type 1 Diabetes Very common Blood Stream • ~95% of cases • Typically adult onset • May be controlled with lifestyle changes & oral hypoglycemic agents • Is caused by insulin resistance (decreased Insulin is injected into soft tissue & works its way into the blood stream insulin receptor response) 5. Insulin is injected. 6. The insulin receptor on liver and muscle cells bind to insulin & take up glucose. 7. Blood sugar levels decline. • Is predisposed by obesity & genetics. Physiology of Type 2 Diabetes Physiology of Type 2 Diabetes Blood Stream Drug 1. Oral Hypoglycemic drugs are used to make the cells respond to the insulin. 2. Blood sugar levels decline. Glucose Tolerance Test Indications of Diabetes • Fasting glucose level ≥ 126 mg/dl. • 2 hour post prandial (fed) blood glucose level ≥ 200 mg/dl. Drug pill is taken orally & works it’s way into the blood stream Blood Stream 1. The pancreas produces insulin. 2. Blood glucose/sugar levels are high. 3. The insulin receptor on the liver and muscle cells are insensitive to the insulin. Measures Carbohydrate Metabolism • • • • Normal diet for 3 days prior to test. Baseline fasting blood sugar level. (Levels ≥126 mg/dl indicate diabetes). Glucose load. 1 gm carbohydrate /Kg body weight or a max of 100 gm for adults. Monitor blood sugar every half hour for six hours. Normal Blood Glucose is 70-99 mg/dl Pre-Diabetes is 100-125 mg/dl 4 1/20/12 Overweight Contributes to Hyperglycemia type 2 diabetes Case Studies: Dick & Jane DICK JANE 300 250 200 Dick's Blood Sugar (mg/dl) Dick's Weight (lbs) 150 100 50 0 -12 -9 -6 -3 0 months Dick’s blood sugar dropped from >600 mg/dl to 90-100 mg/dl over 12 months with weight loss from 262 to 233 lbs. Food Composition The Glycemic Response/Index months Jane’s blood sugar went up from 128 mg/dl to 240 mg/dl after gaining an extra 10lbs. Over 24 months she gradually lost 100 lbs and brought her blood sugar to normal. What is the Glycemic Response/Index? • Simple sugars & foods with a high glycemic index burn up fast & elicit an insulin response. • Complex carbohydrates sustain energy better. • The rise in blood sugar in response to food as compared to glucose. • Glucose is assigned 100. • The Glycemic Index of a food can be useful to anyone concerned with blood sugar control. Glycemic Response of Foods Glycemic Index of Foods • Those with diabetes should eat foods that have a lower glycemic response or slower entrance of glucose into the blood stream. • Foods with high protein, fat, & fiber lower the glycemic response. 5 1/20/12 Summary • Glucose is required by the brain, RBCs & CNS for energy (ATP). • Carbohydrate is the preferred energy source of the body. • All carbohydrate is converted to glucose for energy. • Excess carbohydrate is stored as glycogen. (liver & muscle) • If glycogen stores are full, excess carbohydrate is stored as fat. Summary • Lactose intolerance occurs when the enzyme lactase is missing. • Milk allergy involves immunity. • Hypoglycemia is low blood sugar. Can be reactive, spontaneous, or drug induced. • Hyperglycemia is a sign of diabetes. Summary • Liver glycogen maintains blood sugar for brain, RBCs & CNS function. • Muscle glycogen maintains the working muscle in high intensity exercise. • The hormones insulin & glucagon regulate blood sugar levels. • Insulin decreases while glucagon increases blood sugar. Summary • Diabetes occurs as type 1 & type 2. • Unmanaged diabetes has health implications. • Individuals with diabetes should consider the glycemic response of foods for diet planning. • Selecting low glycemic index foods is useful in controlling blood sugar rises. References for this presentation are the same as those for this topic found in module 3 of the textbook 6 1/20/12 Presentation Overview Lipids in Heart Disease & Cancer Lipids in Heart Disease • Incidence • Contributing factors • Prevention • Blood lipids • Dietary fat • Oxidation & antioxidants • Trans & omega 3 fatty acids • Other factors T-Talk 3.5 By Jennifer Turley and Joan Thompson © 2013 Cengage Heart Disease Lipids in Cancer • The cancer process • Diet & lifestyle & disease risk • P:S ratio • Dietary lipids & disease risk Atherosclerosis • #1 cause of death in America. • 1/3 die of atherosclerosis. • Myocardial infarction and stroke risk increase with atherosclerosis. • Plaques: Deaths per 100,000 • Occlude arterial vessels. • Form from arterial wall injury. • Contain cholesterol (oxidized LDL), platelets, etc. Diet Related Alcohol Related Non-Diet Related Hypertension • Is high blood pressure. • Is a leading cause of arterial wall injury. • Synergizes with atherosclerosis to cause heart disease and stroke. Blood Pressure Classification of Measurements Category Systolic1 Optimal <120 Pre-hypertension 120-139 or 80-89 Stage 1 hypertension 140-159 or 90-99 Stage 2 hypertension ≥ 160 or ≥ 100 1 Systolic Conjunction and Diastolic2 <80 Blood Pressure in mm of mercury (Hg) Blood Pressure in mm of mercury (Hg) 2 Diastolic 1 1/20/12 Reducing Blood Pressure • DASH Diet (The Dietary Approach to Stop Hypertension) • Increase calcium, potassium and magnesium • Low-fat, fiber-rich, moderate protein & carbohydrate • Aerobic exercise • Healthy Body Weight What are the Risk Factors? • • • • • • • • • • Elevated serum cholesterol Genetics Smoking tobacco & drinking alcohol Hypertension Diabetes Obesity Sedentary lifestyle Stress Male gender Consuming a low fiber & high fat diet Elevated Serum Cholesterol & Increased Deaths from Heart Disease Who is Dying of Heart Disease? • • • • • 25-34 years: Men at 3X rate as Women 35-44 years: Men at 2X rate as Women 45-64 years: Women catching up to men 65-75 years: Women catching up to men 75-80 years: Women = Men How can it be prevented? • Lifestyle changes • Less stress, no smoking • Healthy diet • Healthy fats, nutritionally adequate • Regular aerobic exercise • An hour a day • All positively affect blood lipid values and blood pressure Blood Lipids! Serum Triglycerides • VLDL • CHYLOMICRONS mg/dl total cholesterol Serum Cholesterol • LDL (Bad, 77.5%) • HDL (Good, 17.5%) IDL (Neutral, 5%) 2 1/20/12 Serum Triglycerides! Lipid Carrier Molecules • Elevated levels are associated with heart disease. • High triglyceride levels thicken the blood causing hypertriglyceridemia. • Triglycerides are packaged primarily in Chylomicrons and Very Low Density Lipoproteins (VLDL). • A fasting 12 hour blood test is needed to determine an accurate triglyceride level. • <150mg/dl is normal. • 450 mg/dl is like pumping ketchup, causes arterial damage contributing to heart disease and stroke. Serum Cholesterol • Elevated levels are associated with atherosclerosis if 2 other risk factors exist. • Cholesterol is packaged as Low Density Lipoproteins (LDL) and High Density Lipoprotein (HDL). Intermediate Density Lipoprotein (IDL) is present to a minor extent. • HDL’s return cholesterol to the liver for synthesis of bile, hormones, and vitamins. • LDL’s delivers cholesterol to tissue and therefore have a higher plaque effect. Blood Cholesterol Levels & Disease Risk Blood Cholesterol Levels & Disease Risk Total Cholesterol LDL Cholesterol < 100 mg/dl < 200 mg/dl Desirable/Low Risk 200-239 mg/dl Borderline High Risk ≥ 240 mg/dl Optimal 100-129 mg/dl Near optimal 130-159 mg/dl Borderline high High Risk 160-189 mg/dl High ≥ 190 mg/dl Very high HDL Cholesterol < 40 Low (indicates risk) > 60 High Therapeutic Lifestyle Changes (TLC) Diet Summary of the TLC Diet Metabolic Syndrome: If Three or More of These Factors 1. 2. 3. 4. 5. Fasting Blood Triglycerides: ≥150 mg/dl HDL: <50 mg/dl ♀ <40 mg/dl ♂ Blood Pressure: ≥130/85 mm Hg Fasting Blood Glucose: ≥110 mg/dl Waist Circumference: >35” ♀ >40” ♂ Total Fat SFA PUFA MUFA Trans Fatty Acids Carbohydrates Proteins Cholesterol Plant stanols/sterols Soluble Fiber Total Calories 25%-35% of Calories <7% of Calories ≤10% of Calories ≤20% of Calories As low as possible 50%-60% of Calories ~15% of Calories <200 mg/day 2 g/day 10g-25g/day Balance energy intake and expenditure to maintain desirable body weight and prevent weight gain. Expend 200 Calories/day in moderate physical activity. Examples of Food in a 2200 Calorie One Day TLC Diet Grains Vegetables Fruits Low Fat Dairy Lean Meat/Fish/ Alternatives Eggs Oils 7 ounce equivalents with ½ whole grains 3 cup equivalents 2 cup equivalents 3 cup equivalents 6 ounce equivalents, soy protein may replace some animal product <2 yolks/week 6 teaspoon equivalents 3 1/20/12 Dietary Fat & Lipoproteins Fatty Acid Composition of Common Fats • SFA: Increase LDL • PUFA : Decrease LDL & HDL • MUFA: Decrease LDL • Cholesterol: Can Increase LDL • Phospholipids: Not indicated in heart disease Oxidation of Fat Antioxidants • Antioxidants: Prevent oxidation reactions, react • The double bonds of polyunsaturated fatty acids are targets for oxidation (damage by oxygen species). • The double bond breaks with oxidation generating lipid fragments that are very sticky. (-CH2CH=CHCH2- to CH2CHO + CH2CHO). with oxygen radical species directly, & prevent heart disease • Antioxidants vitamins include: vitamin E (alpha-tocopherol), vitamin C (L-ascorbic acid), beta-carotene (provitamin A) • Minerals with antioxidant cofactor functions include: Zinc, Copper, & Iron • The sticky fragments contribute to atherosclerotic plaque formation. Hydrogenation of Fat • Trans fatty acids levels are high in processed foods containing partially hydrogenated oils. • The double bonds from PUFA & MUFA are removed by hydrogenation (adding hydrogen). • The fatty acid becomes more saturated. • Is used in the process of making margarine. • The softer the margarine the less trans fat. • Stick margarine & shortening are highly hydrogenated and partially hydrogenated. Hydrogenation of Fat H+ H+ H+ H+ H+ H+ H+ H+ spotlight Unsaturation Saturation +H2 4 1/20/12 Partial Hydrogenation of Fat • Is done in the food industry. • Many of the double bonds from PUFA & MUFA are removed and many can be chemically modified to a trans fatty acid (TFA) configuration. • TFAs contribute to heart disease. Cis vs. Trans Fatty Acids • Cis: • The naturally occurring configuration in PUFA & MUFA. • Hydrogen atoms are on the same side of the double bond in the fatty acid Carbon chain. • Trans: • Form during the partial hydrogenation process. • A chemical “Fluke” • Hydrogen atoms are on the opposite side of the double bond in the fatty acid Carbon chain. Trans Fatty Acids are Detrimental to Health The Chemical Structure of Cis & Trans Fatty Acids spotlight Consumer Keys for Avoiding Trans Fatty Acids • Read the nutrition facts panel. TFA free is defined as ≤0.5 gm/serving. • Avoid foods with partially hydrogenated oils in the ingredient list (such as cookies, chips, doughnuts) on the food label. • Bake with vegetable oils. • Use margarines that are soft. Choose margarines that are trans fatty acid free. • Avoid deep-fat fried foods like french fries, corn chips, doughnuts, & chicken nuggets. • Avoid high meat and dairy product intake as a natural TFA source from bacterial action on unsaturated fatty acids in the ruminants stomach. • TFAs contribute to heart disease by increasing LDL & decreasing HDL cholesterol & increasing triglycerides. • An intake of 2-3% of energy from TFAs has greater than predicted negative effects from the marked adverse blood lipid changes. TFAs may also contribute to inflammation, endothelial cell dysfunction, and diabetes (insulin resistance). • Intake should be < 1% of energy to as low as possible. Omega-3 Fatty Acids Heart Healthy Omega carbon Linoleic Acid An Omega-6 fatty acid Omega carbon Alpha-Linolenic Acid An Omega-3 fatty acid 5 1/20/12 How Do Omega-3 Fatty Acids Work? • They affect the synthesis of eicosanoid hormone like compounds such as prostaglandins & leukotrienes. • The compounds produced from omega 3 fatty acids: • Decrease blood clotting (prevent plaque build-up) • Decrease blood pressure (prevent atherosclerosis) • Decrease blood total cholesterol, LDL cholesterol, & triglycerides & increase HDL cholesterol) • Decrease inflammation (prevent arthritis, asthma) • Increase immunity (prevent cancer) Omega-3 Fatty Acids in Fish • Best Sources: • • • • • • Good Sources: Salmon Herring Mackerel Tuna Whitefish To avoid mercury contamination, eat fish that live closer to the surface and have a shorter lifespan. • • • • • • • • Cod Flounder Halibut Mahi Mahi Orange Roughy Sea Bass Clams Scallops Other Factors in Heart Disease • High doses of Niacin: Increases HDL, decreases LDL. • Statin type cholesterol lowering drugs: Reduce the synthesis of cholesterol in the liver. • Cholesterol absorption inhibitor drugs. • Benecol spreads: Contain plant stanol esters that reduce the absorption of cholesterol in the digestive tract. • Wine: Reduces blood viscosity. Red wine and/or grape juice increases HDL. • Alcohol: 1 serving per day decreases risk of a cardiovascular accident. It is an anticoagulant. • Aerobic Activity: Increases HDL, decreases LDL. • Soluble Fiber: Decreases LDL. • Soy Protein: Increases HDL, decreases LDL. American Heart Association omega 3 fatty acid recommend • Consume 0.5-1.8 grams of omega-3 fatty acids per day as fatty fish or supplements. • The omega-3 fatty acids in fish are called EPA & DHA. • Consume 1.5-3.0 grams alpha-linolenic acid (an omega-3 fatty acid) per day. • Plant sources of omega-three fatty acids flax seed, walnuts, & canola oil. Homocysteine in Heart Disease • Homocysteine is an amino acid intermediate of cysteine & methionine metabolism. • Elevated levels of homocysteine cause arterial wall damage & contribute to heart disease. • Folic acid (folate), B6 & B12 function as cofactors for the enzymes driving the inter conversion of cysteine & methionine, thus adequate intakes prevent hyperhomocystemia. methionine homocysteine cysteine Lipids in Cancer • Cancer is the 2nd leading cause of death in Americans. • It is characterized by uncontrolled cell growth. • It occurs through a process of initiation, promotion, and progression. 6 1/20/12 Carcinogenesis Cancer Risk • Increased Cancer Risk by Lifestyle Practices – Smoking tobacco, UV light, Obesity, Sedentary Lifestyle • Increased Cancer Risk by Dietary Practices – ~ 45% of all cancer deaths are diet-related – Low F&V, antioxidant nutrient, & fiber intake – High total fat and PUFA, sodium intake – P:S ≥3:1 + high fat diet = cancer risk – P:S ≤0.33:1 (or ≤1:3) + high fat diet = heart disease risk Sample P:S Ratio Calculation • Kathy ate a high fat diet. – 104 gm PUFA & 30 gm SFA • What is her P:S ratio? Dietary Lipids & Disease Risk Dietary Factor Heart Disease Cancer Low fat intake Prevents disease Prevents disease Does not contribute to disease Does not contribute to disease Contributes to disease Contributes to disease (20-25% of total Calories) Ø 104 ÷ 30 = 3.47. This # is placed in the P position of the ratio – The S position is always assigned the # 1 • The P:S is 3.47:1 • Is the ratio increasing disease risk? – This P:S ratio is increasing risk for cancer – Remember that you do want enough PUFA to get your essential (linoleic and alpha-linolenic) fatty acid needs met. Fatty Acids & Disease Risk Moderate fat intake (25-35% of total Calories) High fat intake (>35% of total Calories) Summary How to prevent heart disease High SFA Low MUFA Low PUFA Increases total blood cholesterol, LDL (is not ideal) Is associated with heart disease (is atherogenic) Low SFA Low MUFA High PUFA Decreases total blood cholesterol, HDL & LDL (is not ideal) Increases cancer risk (is tumorgenic) Low SFA High MUFA Adequate PUFA Decreases total blood cholesterol, LDL (is ideal) Is not associated with cancer or heart disease risk (is not tumorgenic or atherogenic) • Avoid dietary cholesterol & saturated fat. • Avoid hydrogenated or partially hydrogenated fat (trans-fatty acids). • Consume MUFA and omega 3 fatty acids. • Protect PUFA, MUFA, & LDL with antioxidants. • Consume adequate folate to prevent hyperhomocystemia. • Consume soluble fiber, soy, and plant stanols/sterols. • Avoid cigarette smoking. • Exercise (especially aerobic). 7 1/20/12 Summary How to prevent cancer • Choose to eat mostly plant foods. – Eat plenty & a variety of whole grains, fruits, & vegetables! • Avoid high fat diets especially saturated fat & omega-6 fatty acids. • Consume an antioxidant-rich diet. • Practice all aspects of a sound diet: Calorie control, adequacy, balance, moderation, and variety. References for this presentation are the same as those for this topic found in module 3 of the textbook 8