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NUTRITION I & II: METABOLIC AND DIETARY ASPECTS D. C. MIKULECKY PROFESSOR OF PHYSIOLOGY VIRGINIA COMMONWEALTH UNIVERSITY NUTRITION, ENERGY BALANCE AND TEMPERATURE REGULATION ENERGY SOURCES ENERGY METABOLISM REGULATION OF ENERGY METABOLISM BASAL METABOLIC RATE ENERGY THE CAPACITY TO DO WORK THE CALORIE IS THE AMMOUNT OF HEAT ENERGY NECESSARY TO RAISE THE TEMPERATURE OF 1 GRAM OF WATER 1 DEGREE CENTIGRADE THE NUTRITIONAL CALORIE IS 1000 CALORIES OR THE KILOCALORIE ENERGY BALANCE WITH RESPECT TO THE BODY INPUT - OUTPUT = STORAGE OR DEPLETION (CONTINUITY EQUATION ( E/t = 2E) ) OUTPUT = INTERNAL WORK + EXTERNAL WORK INTERNAL WORK ------> HEAT STORAGE AND/OR DEPLETION NUETRAL ENERGY BALANCE OCCURS WHEN INPUT AND OUTPUT MATCH POSITIVE ENERGY BALANCE OCCURS WHEN INTAKE EXCEEDS OUTPUT ENERGY IS STORED AS GLYCOGEN OR FAT NEGATIVE ENERGY BALANCE OCCURS WHEN OUTPUT EXCEEDS INTAKE- ENERGY STORES ARE DEPLETED FOOD AS STORED FUEL 3500 CALORIES = 1 LB OF BODY MASS ENERGY INPUT 50% GOES TO ATP 50% GOES TO HEAT CARBOHYDRATE, FAT AND PROTEIN FOOD AS FUEL CARBOHYDRATE 4 CAL/G PROTEIN 4 CAL/G FAT 9 CAL/GRAM ETHANOL 7 CAL/G FOOD INTAKE CONTROLED BY HYPOTHALAMUS FEEDING CENTERS SATIETY CENTERS CONTROL OF FOOD INTAKE POORLY UNDERSTOOD OBESITY IS TOO MUCH STORED FAT LIPOSTATIC THEORY GI DISTENSION THEORY GLUCOSTATIC THEORY CCK SECRETION THEORY PSYCHOSOCIAL INFLUENCES FOOD AS STORED FUEL 3500 CALORIES = 1 LB OF BODY MASS THE METABOLIC RATE METABOLIC RATE = ENERGY EXPENDITURE PER UNIT TIME (Calories/hour) FACTORS INFLUENCING METABOLIC RATE EXERCISE FOOD INTAKE SHIVERING ANXIETY GENERAL ADAPTATION SYNDROME FLIGHT OR FIGHT EPINEPHRINE CRH-ACTH-CORTISOL RENIN-ANGIOTENSIN-ALDOSTERONE VASOPRESSIN COORDINATED BY HYPOTHALAMUS CAN BE INDUCED PSYCHOSOCIALLY ANABOLISM VS CATABOLISM BUILD UP VS BREAKDOWN OF LARGE MOLECULES ANABOLISM REQUIRES ENERGY (ATP) CATABOLISM:ENERGY PRODUCTION THE ROLE OF VITAMINS AND MINERALS IN METABOLISM COFACTORS FOR ENZYMES (MOST WATER SOLUABLE VITAMINS) WATER SOLUABLE VITAMINS B1 (THIAMINE): B2 (RIBOFLAVIN) NIACIN C (ASCORBIC ACID) FOLIC ACID B6 ( PYRIDOXINE, PYRIDOXAL, PYRIDOXAMINE) B12 PANTHOTHENIC ACID BIOTIN FAT SOLUABLE VITAMINS ABSORBED ALONG WITH FATS VITAMIN A: PRECURSOR OF RHODOPSIN VITAMIN D: CALCIUM METABOLISM VITAMIN E : LIPID ANTIOXIDANT VITAMIN K: BLOOD CLOTTING CONTROL OF FUEL METABOLISM GLYCOGENESIS GLYCOGENOLYSIS GLUCONEOGENESIS PROTEIN SYNTHESIS PROTEIN DEGRADATION FAT SYNTHESIS FAT BREAKDOWN GLYCOGENESIS GLYCOGEN IS A BRANCHED POLYMER OF GLUCOSE ATORED IN THE LIVER (ABOUT 100g) AND MUSCLE CELLS(ABOUT 200g). ENOUGH FOR PART OF A DAY. SYNTHESIS IS BY SEPARATE PATHWAY FROM BREAKDOWN HIGHLY REGULATED BY INSULIN GLYCOGENOLYSIS BREAKDOWN OF GLYCOGEN STORES INTO GLUCOSE REGULATES BLOOD GLUCOSE BETWEEN MEALS HOMONALLY CONTROLLED (GLUCAGON, EPINEHRINE, NOREPINEPHRINE AND CLUCOCORTICOIDS) GLUCONEOGENESIS PRUCURSORS ARE 3 AND 4 CARBON COMPOUNDS VIA FRUCTOSE PHOSPHATE GLUCAGON CONTROLLED MAIN PRECURSOR ALANINE AND OTHER AA PROTEIN DEGRADATION USUALLY BALANCED BY SYNTHESIS NO ENERGY STORES IN FORM OF PROTEIN CAN BE ENHANCED BY GLUCAGON AND OTHER HORMONES LEADING TO GLUCONEOGENESIS FAT SYNTHESIS GLUCOSE - FATTY ACID CYCLE FATTY ACIDS PRODUCED CONSTANTLY IN ADIPOSE TISSUE. BECOME FFA OR BECOME TRIGLYCERIDES DEPENDING ON GLYCEROL PHOSPHATE FROM GLUCOSE OXIDATION GLUCOSE - FATTY ACID CYCLE ADIPOCYTE MYOCYTE FFA FATTY ACIDS KETONES (-) CO2 (-) BLOOD GLUCOSE-6-P TRIGLYCERIDES GLUCOSE FAT BREAKDOWN MOST CONCENTRATED ENERGY STORE ONE DAY’S NEEDS CAN BE MET BY LESS THAN 250g (70kg MAN 40 DAYS) STORED AS TRIGLYCERIDES IN ADIPOSE TISSUE AND MUSCLE ENHANCED BY GLUCAGON TRIGLYCERIDE LIPASE GLYCEROL MUST PASS TO BLOOD TO BE RECYCLED BASAL METABOLIC RATE BODY’S “IDLING SPEED” DIRECT CALORIMETERY INDIRECT CALORIMETERY (SEE LAB NOTES FROM DEC.2) PROTEIN SYNTHESIS USUALLY BALANCED WITH BREAKDOWN INSULIN INCREASES SYNTHESIS GLUCAGON IS ANTAGONISTIC ESSENTIAL AMINO ACIDS VALINE THREONINE ISOLEUCINE LEUCINE HISTADINE (IN INFANTS) METHIONINE, PHENYLALANINE TRYPTOPHAN LYSINE PROTEIN QUALITY ONLY 20% OF THE RDA NEEDS TO BE COMPLETE PROTEIN (11 GRAMS FOR MALES 9 GRAMS FOR FEMALES …A LITTLE MORE THAN SUPPLIED BY A GLASS OF MILK) MORE DIVERSITY IS THE KEY THOUGH: 60% RDA FROM GRAIN, 35% FROM LEGUMES, 5% FROM GREEN LEAFY VEGETABLES PLANTS AND PROTEIN QUALITY FOOD SOURCE LIMITING AA ABUNDANT AA WHOLE GRAINS THREONINE METHIONINE, LYSINE CORN LYSINE, THREONINE, TRYPTOPHAN LYSINE , OATS, RICE WHITE FLOUR LEGUMES SULFUR AA, TRYPTOPHAN LYSINE, THREONINE PLANTS AS A PROTEIN SOURCE 65% OF THE PER CAPITA SUPPLY WORLD WIDE 32% OF THE PER CAPITA SUPPLY IN THE US PROTEIN SOURCES-EXCEPTIONS SOYBEANS QUINONA SPINACH HAVE THE SAME QUALITY AS MILK INCOMPLETE PROTEINS NEEDED TO MEET REQUIREMENTS 2 2/3 CUPS COOKED WHEAT 3 CUPS COOKED RICE 5 3/4 SLICES BASIC BREAD 3 CUPS DICED POTATOES 1/3 CUP SOY SPREAD 1/2 CUP WHEAT GERM 2 3/4 CUPS RICE WITH 1/3 CUP COOKED PEAS SOME DISEASES LINKED WITH DIET CANCER HEART DISEASE HIGH BLOOD PRESSURE OBESITY DIVERTICULITIS FOOD INGREDIENTS AND DISEASE REFINED SUGAR FAT SALT LOW IN FIBER CANCER AND DIET: PHYTOCHEMICALS FOUND ONLY IN PLANTS IMMUNE FUNCTION HORMONE BALANCE DETOXIFICATION CANCER AND DIET N.R.C.RECOMMENDATIONS EAT LESS FAT (30% OR LESS 0F TOTAL CALORIES) EAT FRUITS, VEGITABLES, AND WHOLEGRAIN CEREAL FOODS EVERY DAY (ESPECIALLY THOSE HIGH IN VITAMINS A AND C) AVOID HIGH DOSE SUPPLIMENTS OF VITAMINS OR OTHER NUTRIENTS ALCOHOL ONLY IN MODERATION SOME WAYS TO CUT DOWN ON FAT EAT MORE VEGETARIAN MEALS EAT MORE FRESH FRUIT OR YOGURT INSTEAD OF DESSERTS USE YOGURT AS DRESSING INSTEAD OF OIL USE FRESH HERBS INSTEAD OF BUTTER (AND INSTEAD OF SALT) TYPES OF VEGETARIAN DIETS VEGAN: NO ANIMAL PRODUCTS (NEED DIETARY SUPPLIMENTS AND VARIED PROTEIN SOURCES) LACTO: +DAIRY PRODUCTS LACTO-OVO: +EGGS FIBER ROUGHLY SPEAKING, EVERYTHING IN PLANT FOODS OUR DIGESTIVE ENZYMES CAN NOT BREAK DOWN NURTURES AEROBIC BACTERIA IN GUT SOLUABLE FIBER REDUCES INSULIN NEED IN DIABETICS CHELATORS-INCREASE NEED FOR MINERALS TYPES OF FIBER PECTINS: IN CELL WALL OF FRUITS, BIND BILE SALTS GUMS: STICKY SUBSTANCES EXUDED BY PLANTS, LOWER CHOLESTEROL UPTAKE AND SLOW SUGAR ABSORPTION CELLULOSE: PLANT CELL WALLS, BULK AND TOXIN ELIMINATION HEMICELLULOSES: PLANT CELL WALLS, BULK LIGNIN: ROOT VEGETABLES, BULK EFFECT ON MICROFLORA LOWER TOTAL ANAEROBIC, IN PARTICULAR, CLOSTRIDIUM DIET CAN ALTER THE METABOLIC ACTIVITY OF THE FLORA MEAT AND UNREFINED SUGAR INCREASES UNWANTED BACTERIA VEGETARIAN DIET LOWERS RISKS OF BOWEL CANCER RECOMMENDED FIBER INTAKE 20 - 25 g/day WITH AN UPPER LIMIT OF 35 g/day FAMILY HISTORY OF DIETIMPLICATED CANCER 35-40 g/day DIABETICS UP TO 50 g/day SOURCES OF FIBER LEGUMES (ALSO PROTEIN SOURCE) FRUITS AND VEGETABLES WHOLE GRAIN CEREALS AND FLOURS PROPOSED MECHANISMS FOR FIBER CANCER PREVENTION INCREASED FECAL BULK DECREASES CARCINOGEN CONCENTRATION CHANGE IN FLORA SHORTENED TRANSIT TIME DECREASES CONTACT TIME AND TIME FOR SYNTHESIS OF TOXINS CHANGE IN pH CHELATORS LOWER MINERAL ABSORPTION PHYTATES OXALATES
