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