NUTRITION, ENERGY BALANCE AND TEMPERATURE REGULATION D. C. MIKULECKY PROFESSOR OF PHYSIOLOGY AND FACULTY MENTORING PROGRAM
May 11, 2015
NUTRITION, ENERGY BALANCE AND TEMPERATURE REGULATION
D. C. MIKULECKYPROFESSOR OF PHYSIOLOGY
ANDFACULTY MENTORING PROGRAM
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
INPUT - OUTPUT = STORAGE OR DEPLETION
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
THE METABOLIC RATE
METABOLIC RATE = ENERGY EXPENDITURE PER UNIT TIME
(Calories/hour)
FACTORS INFLUENCING METABOLIC RATE
• EXERCISE
• FOOD INTAKE
• SHIVERING
• ANXIETY
BASAL METABOLIC RATE
• BODY’S “IDLING SPEED”
• DIRECT CALORIMETERY
• INDIRECT CALORIMETERY
CONTROL OF FOOD INTAKE
• POORLY UNDERSTOOD• OBESITY IS TOO MUCH STORED FAT• LIPOSTATIC THEORY• GI DISTENSION THEORY• GLUCOSTATIC THEORY• ISCHYMETRIC THEORY• CCK SECRETION THEORY• PSYCHOSOCIAL INFLUENCES
FOOD INTAKE
• CONTROLED BY HYPOTHALAMUS
• FEEDING CENTERS
• SATIETY CENTERS
FOOD AS FUEL
• CARBOHYDRATE 4 CAL/G
• PROTEIN 4 CAL/G
• FAT 9 CAL/GRAM
• ETHANOL 7 CAL/G
FOOD AS STORED FUEL
• 3500 CALORIES = 1 LB OF BODY MASS
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
OATS, RICE,WHITE FLOUR
LYSINE
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 WHOLE-GRAIN 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 DIET-IMPLICATED 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
TEMPERATURE REGULATION
• INTERNAL CORE TEMPERATURE IS 100 DEGREES F
• HEAT BALANCE RESEMBLES ENERGY BALANCE
• HEAT EXCHANGE WITH THE ENVIRONMENT
HEAT BALANCE RESEMBLES ENERGY
BALANCE
INPUT - OUTPUT = + >>RISE IN TEMPERATURE
INPUT - OUTPUT = - >>FALL IN TEMPERATURE
INPUT - OUTPUT = 0 >>NO CHANGE IN TEMPERATURE
HEAT EXCHANGE WITH THE ENVIRONMENT
• HEAT ALWAYS MOVES FROM HIGH TEMPERATURE TO LOW
• RADIATION
• CONDUCTION
• CONVECTION
• EVAPORATION
RADIATION
• THE EMISSION OF HEAT ENERGY BY ELECTROMAGNETIC RADIATION, IN THE FORM OF HEAT WAVES
CONDUCTION
• TRANSFER OF HEAT BETWEEN BODIES AT DIFFERENT TEMPERATURE IN CONTACT WITH EACH OTHER
CONVECTION
• TRANSFER OF HEAT BY AIR CURRENTS
EVAPORATION
• THE TRANSITION FROM LIQUID TO GAS USES HEAT ENERGY
• UNCONTROLLED: FROM RESPIRATORY TRACT AND SKIN SURFACE
• CONTROLLED: SWEATING
THERMOREGULATION PATHWAYS
• INPUTS TO HYPOTHALAMUS
• BEHAVIORAL RESPONSES
• SHIVERING
• VASODILATION OR CONSTRICTION OF BLOOD VESSELS IN THE SKIN
• SWEATING
INPUTS TO HYPOTHALAMUS
• FROM THE SKIN: PERIPHERAL THERMORECEPTORS
• FROM THE CORE: CENTRAL THERMORECEPTORS
BEHAVIORAL RESPONSES
• MOVE TO A MORE SUITABLE LOCATION (SHADE, INDOORS, ETC.)
• CHANGE CLOTHING
• CHANGE ACTIVITY LEVEL
SHIVERING
• RHYTHMIC, OSCILLATING SKELETAL MUSCLE CONTRACTIONS (ABOUT 10-20 PER SECOND)
• MAY INCREASE INTERNAL HEAT PRODUCTION 2-5 TIMES.
• CHEMICAL THERMOGENESIS (BROWN FAT)
VASODILATION OR CONSTRICTION OF BLOOD VESSELS IN THE SKIN
• SKIN BLOOD FLOW VARIES FROM 400 ML/MIN TO 2,500 ML/MN
• VASOCONSTRICTION OR DILATION OF THE BLOOD VESSELS IN THE SKIN IS CONTROLLED BY THE HYPOTHALAMUS
SWEATING
• CONTROLED BY SYMPATHETIC NERVOUS SYSTEM
• DEPENDS ON RELATIVE HUMIDITY OF SURROUNDING AIR
CENTRAL CONTROL
• HYPOTHALAMUS CONTROLS
• HEAT PRODUCTION
• HEAT LOSS
• HEAT CONSERVATION
• REGULATES CORE TEMPERATURE HOMEOSTATICALLY
FEVER
• FIGHTS INFECTION
• ENDOGENOUS PYROGEN FROM WBC
• LOCAL RELEASE OF PROSTAGLANDINS
• “RESETS THERMOSTAT”
• SHIVERING
• SKIN VASOCONSTRICTION