NUTRITION, ENERGY BALANCE
AND TEMPERATURE REGULATION
D. C. MIKULECKY
PROFESSOR OF PHYSIOLOGY
AND
FACULTY 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 INTAKEENERGY 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
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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
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VALINE
THREONINE
ISOLEUCINE
LEUCINE
HISTADINE
(IN INFANTS)
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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
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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
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CANCER
HEART DISEASE
HIGH BLOOD PRESSURE
OBESITY
DIVERTICULITIS
FOOD INGREDIENTS AND DISEASE
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REFINED SUGAR
FAT
SALT
LOW IN FIBER
CANCER AND DIET: PHYTOCHEMICALS
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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
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
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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 1020 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
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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