NUTRITION
Diet & nutritionnutrients =Nutrients are the
constituents of food necessary to sustain the normal functions
of the body. Energy balance. Over nutrition. Body mass index Wt in
kg/Ht in meter 2 squared A way of expressing relative obesity to
height Desirable range is b/w 20 & 05/26/10
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Energy metabolismMetabolism of food stuff
exergonic reaction & endergonic reaction energy expenditure
by the body for two resions 1, utilization for physical work 2,
utilization for involuntary work this part of expenditure is
constant and at a basal rate.
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CALORIC VALUE OF FOODOn burning different foodstuffs
different
amount of energy How much heat will be obtained by burning a
particular food stuff is expressed by caloric value Definition The
amount of heat energy obtained by burning 1.0 gm of the food stuff
completely in the presence of O2 Bomb calorimeter
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CALORIEUnit of energy (c) Def-
the amount of heat required to raise the temp- of 1.0 gm of
water by 1c (from 15 16c).this is ordinary calorie and is too
small. KILOCALORIE A unit thousand time of the ordinary calorie is
called Kilocalorie or simply Calorie C. Calorie in biological
science always means a Kilocalorie
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Calories obtained / gm
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Energy required = varies
Basal metabolism
but the rate of energy production in individual by its overall
cellular metabolism is more or less constant under some standard
/basal conditions basal conditions are 1.Person should be awake but
2.At complete rest both physically and mentally 3.Post absorptive
state(12-18 hrs after meal) 4.Should be in reclining position
5.Environmental temp-2oc - 25c 6.Comfortable humidity and
pressure05/26/10 7
BMRRate of energy production under basal
conditions per unit of time and per sq meter of body surface
Normal in adult male =40C/sqm/hr in adult female= 37C/sqm/hr
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Factors influencing BMR1.age 2.sex 3.surface area 4.climate
5.state of nutrition 6.body tem7.barometric pressure 8.habits
9.drugs 10.hormones 11.pregnency05/26/10 9
Variations in BMRPATHOLOGICAL Fever Diseases having increased
cellular activity Endocrine disease hyperthyroid hypothyroid
Cushing's disease addision,s disease IMPORTANCE OF BMR05/26/10
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QUOTIENT(RQ)
or respiratory coefficient Definition Is the ratio of volume of
CO2 produced by the volume of O2 consumed (CO2/O2) during a given
time.body with energy. forms of indirect calorimetry is a unit less
number used in calculations of basal metabolic
an indicator of which fuel is being metabolized to supply
the
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rate(BMR)when estimated from carbon dioxide production. Reflects
cellular processes Proportional increase or decrease of CO2
produced and O2 utilized, will keep the ratio unchanged. But any
disproportionate variation will be reflected by a corresponding
change in the ratio. RQ indicates type of the food burning inside
the body or conversion of one food stuff into11
Differ from RQ
RESPIRATORY EXHANGE RATIO (R)
It is the ratio of CO2 & O2 at any given time
whether or not equilibrium has been reached. It is affected by
factors other than metabolismR rises during hyperventilation
falls after exercise rises in metabolic acidosis falls in
metabolic alkalosis
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RQNormal RQ = 0.85 in healthy adult, on mixed
diet. Carbohydrates ~ 1.0 Protein ~ 0.81. ( due to the
complexity of the various ways in which different amino acids can
be metabolized, no single RQ can be assigned to the oxidation of
protein in the diet. Lipids ~ 0.7 Excess glucose leads to a RQ >
1.0. The excess glucose, converted to CO2, increases minute
ventilation in order to prevent respiratory acidosis. An RQ > 1
indicates net lipogenesis
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Factors affecting RQ1, DIET carbohydrates (C6 H12 O6) = RQ = 1.
(the volume of CO2 produced is the same as the volume of O2
consumed) the amount of O2 present is just sufficient to oxidize
the H present in the same molecule. 6o2 6CO2 C6H12O6 + = + 6H2O CO2
produced/O2 consumed=6/6=1
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RQ of FatIt is lowest As fat is a O2 poor compound. The O2
present in it can not fully oxidizes the H O2 consumed from outside
Oxidation of 2C15H110O2 + 163 O2 114 CO2 + 110H2O RQ = 114/163
=0.70
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RQ for protein
RQ =0.8 2C3H7O2N + 6O2 (NH2)2CO + 5CO2 + 5H2O RQ = 5/6 = 0.8
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2, effect of interconversion in the bodyWhen CHO are converted
into Fat
RQ will rise O2 rich compound is converted into O2 O2 liberated
from CHO, consequently less O2 is required from outside CO2 is
produced more than O2 consumed so RQ rises A reversal when Fat is
converted into CHO
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Clinical conditions areIn acidosis = RQ
consumption. In alkalosis = RQ In febrile conditions =RQ due
to> breathing > CO2 production >CO2 wash. In diabetes
mellitus, RQ fall In starvation = fall
, CO2 out put > then O2
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SIGNIFICANCE OF RQ1, DETERMINE METABOLIC RATE 2,TYPE OF FOOD
BURNING 3,DIAGNOSIS OF VARIOUS DISEASES
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Caloric or energy requirementsthe average dietary energy intake
predicted to maintain an energy balance in a healthy adult of a
defined age, gender, and height whose weight and level of physical
activity are consistent with good health.
Or enough food to replace the calories expended per day
sedentary adults = 30 kcal/kg/day to maintain body weight;
moderately active adults = 35 kcal/kg/day and very active adults
require 40 kcal/kg/day. ( 2,000 or 2,500 kcal/day.)
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How energy is used in the body1. BMR (RMR) wt= 70 kg (male) SA =
1.7 sq metre 70/1.7 = 41 C/sq metre/hr 1.7 41 24 =1672 c/ day
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2, Thermic effect of food or SDAThe production of heat by the
body
increases as much as 30% above the resting level during the
digestion and absorption of food. This effect is called the thermic
effect of food or diet-induced thermogenesis. Over a 24hour period,
the thermic response to food intake may amount to 510% of the total
energy expenditure05/26/10 22
3, physical activityInfluence of muscular work on total
metabolism Influence of mental work on total metabolism
Influence of sleep on total metabolism
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Obesity
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INTRODUCTIONAll components of diet are necessary Qualitative
& Quantitative requirement Quantitative requirement varies with
age, sex & life
style of individual. Overt nutritional def- is rare (in deprived
persons) Some degree of nutritional def- is present in Poor,
elderly , growing children, pregnant women lactating mother, ill,
convalescing pts, alcoholics, strict vegetarians, malabsorption and
more deprived population
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DefinitionObesity is an abnormal accumulation of body
fat, usually 20 percent or more over an individual's ideal body
weight.
Definition of Overweight & ObesityUsing BMI
ITEMSUNDER WEIGHT
BMI 18.5 18.5 24.9 25.0 29.9 30.0 34.9 35.0 39.9
GRADE
NORMALOVER WEIGHT
OBESITY OBESITY
I II III
EXTREME OBESITY 40
body mass index(BMI), orQuetelet index,a statistical measure
which compares a
person's weight and height. Though it does not actually measure
thepercentage of body fat, it is used to estimate a healthy body
weightbased on a person's height. Body mass index is defined as the
individual's body weight divided by the square of his or her
height.(kg/m2). a BMI chart,
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A graph of body mass index .World Health Organization.
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TYPES OF OBESITYA immediate 1, EXOGENOUS 2, ENDOGENOUS B
pathological 1, HYPERPLASTIC 2,HYPERTROPHIC
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Factors predispose to obesityGenetic familial tendency. Sex
women more susceptible . Activity lack of physical activity.
Psychogenic emotional deprivation,
depression . Social class poorer classes. Alcohol problem
drinking. Smoking cessation smoking. Prescribed drugs tricyclic
derivatives.
Metabolic changes in obesityNot permanent can be changed by
wt
reduction
usually hyperinsulinaemia in fat metabolism
TG level will rise Serum cholesterol will be high FFA normal 2.
in CHO metabolism More conversion to fat 3. acid base changes
(obesity hypoventilation syndrome)
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LEPTIN
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LeptinProtein hormone secreted by adipocytes Levels correlate
with lipid content of cells Leptin acts on the hypothalamus to
reduce
hunger and to stimulate energy expenditure
GhrelinHormone secreted in the stomach Acts on the hypothalamus
to stimulate appetite Levels peak just before meals and drop
afterward
Health Consequences of ObesityMajor cause of
preventable death Increase in mortality from all causes Increase
in risk for these cancers Endometrium Breast Prostate Colon
Increase in risk of: Hypertension Dyslipidemia Diabetes type 2
Coronary artery disease Stroke Gallbladder disease Osteoarthritis
Sleep apnea & respiratory problems
BALANCED DIETA DIET when it include
proportionate quantities of food items form different food
groups to supply the essential nutrients in complete fulfillment of
the requirement of the body BASED ON 1.easily available, 2.within
economic means. 3.easily digestible 4.should fit with local food
habits 5.Should contain enough roughage material
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2nd lecture
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Basic food groupsGroup Group Group Group Group
1 2 3 4 5
= = = = =
dairy products & milk Meat Green leafy vegetables Fruits
cereals
A balanced diet can planed by keeping
1.Age 2.Sex 3.Caloric requirement 4.From basic food groups
5.Within purchasing capacity05/26/10 37
BASIC FUNCTION OF NUTRIENTSCarbohydrate Fats Protein
energy production protection against growth & repair
infections
Vitamins Minerals water
regulation of tissue38
functions05/26/10
Plan of balanced dietAge Sex physical activity special
nutritional needs Economic status Need for minimum cost Varieties
from basic food groups
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protein in nutrition
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protein(essential AA)
Biological value AA composition Balance of AA Availability of
amino acid from foods Relation ship of AA
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A, BIOLOGICAL VALUEThe % age of absorbed Nitrogen which is
retained
in the body. Several methods of calculation By measurement 1.wt
gain in gms / gms of protein consumed 2. on retention of absorbed
N2 First animal is kept protein free diet for two days, fecal &
urinary N2 estimated. Then animal is fed with measured amount of
test protein and fecal & urinary N2 determined again05/26/10
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B, amino acid compositionEssential AA+ available together +
simultaneously, so they can be utilized for protein
synthesis
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Quantity of proteinOptimum requirement = 1gm/kg of body wt
Critical intake level = 0.25 0.33 gms/kg body
wt +ve & - ve nitrogen balance chemical score It is the
ratio b/w the contents of the most limiting AA in the test protein
to the contents of the same AA in egg protein is expressed in %.
Egg = reference protein05/26/10 44
Protein deficiencyCauses Consequences Growth retardation Weigh
loss Anemia Delayed wound healing Fatty liver due to impaired
apoprotein synthesis Decreased plasma proteins Infections Hormone
def-.05/26/10 45
Protein calorie malnutritionA pathological state resulting from
absolute or
relative deficiency of one or more essential nutrients Primary
malnutrition Secondary malnutrition CLASSIFICATION a. General
classification Mid arm circumference= < 75 % of the expected
Skin fold thickness by herpenden caliper Quac strip 05/26/10
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ContWelcome classification Edema present Weight for age,
kwashiorkor 80 60% of std Marasmic Wt for age < 60% of std
kwashiorkorEdema absent Ponderal retardation marasmas
Gomez classification 1st degree Wt is 75 95 % of the expected wt
2nd degree Wt is 60 75 % of the expected wt 3rd degree Below 60 %
of expected wt05/26/10 47
Assessment of Nutr statusDirectClinical Anthropometric Dietary
Laboratory
IndirectHealth statistics Ecological variables
Clinical AssessmentUseful in severe forms of PEM Based on
thorough physical examination
for features of PEM & vitamin deficiencies. Focuses on skin,
eye, hair, mouth & bones. Chronic illnesses & goiter to be
excluded
ANTHROPOMETRYObjective with high specificity &
sensitivity Measuring Ht, Wt, MAC, HC, skin fold thickness,
waist & hip ratio & BMI Reading are numerical &
gradable on standard growth charts Non-expensive & need minimal
training
KWASHIORKORCecilly Williams, a British nurse, had
introduced the word Kwashiorkor to the medical literature in
1933. The word is taken from the Ga language in Ghana & used to
describe the sickness of weaning.
ETIOLOGYKwashiorkor can occur in infancy but its
maximal incidence is in the 2nd yr of life following abrupt
weaning.Kwashiorkor is not only dietary in origin.
Infective, psycho-socical, and cultural factors are also
operative.
ETIOLOGY (2)Kwashiorkor is an example of lack
of physiological adaptation to unbalanced deficiency where the
body utilized proteins and conserve S/C fat. One theory says Kwash
is a result of liver insult with hypoproteinemia and oedema. Food
toxins like aflatoxins have been suggested as precipitating
CONSTANT FEATURES OF KWASHOEDEMA PSYCHOMOTOR GROWTH MUSCLE
CHANGES
RETARDATION
WASTING
USUALLY PRESENT SIGNSMOON FACE HAIR CHANGES SKIN DEPIGMENTATION
ANAEMIA
OCCASIONALLY PRESENT SIGNSHEPATOMEGALY FLAKY
PAINT DERMATITIS CARDIOMYOPATHY & FAILURE DEHYDRATION
(Diarrh. & Vomiting) SIGNS OF VITAMIN DEFICIENCIES SIGNS OF
INFECTIONS
DD of Kwash DermatitisAcrodermatitis Entropathica Scurvy
Pellagra Dermatitis Herpitiformis
MARASMUSThe term marasmus is derived from the
Greek marasmos, which means wasting. Marasmus involves
inadequate intake of protein and calories and is characterized by
emaciation.Marasmus represents the end result of
starvation where both proteins and calories are deficient.
MARASMUS/2Marasmus represents an adaptive
response to starvation, whereas kwashiorkor represents a
maladaptive response to starvationIn Marasmus the body utilizes all
fat
stores before using muscles.
EPIDEMIOLOGY & ETIOLOGYSeen most commonly in the first year
of
life due to lack of breast feeding and the use of dilute animal
milk. Poverty or famine and diarrhoea are the usual precipitating
factors Ignorance & poor maternal nutrition are also
contributory
Clinical Features of MarasmusSevere wasting of muscle & s/c
fats Severe growth retardation Child looks older than his age No
edema or hair changes Alert but miserable Hungry Diarrhoea &
Dehydration
CHO ROLE IN DIETNORMALLY 55 65 % OF THE TOTAL FOOD
CALORIES Protein sparing action Role of cellulose Excessive
intake Intestinal disturbances(bacterial fermentation)
Galactose------ cataract.
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Daily FAT requirements20 35 % of energy should be provided
by
fat/day -6- PUFA ------- 5 10 % -3- PUFA --------- 0.5 1.2 %
PLASMA CHOLISTEROL & C H D plasma cholesterol arises from 1,
diet 2, endogenous Transported as lipoprotein.
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Thank You!
