Requirement for nutrients

NUTRITIONAL REQUIREMENT
INFANCY TO OLD AGE
Submitted to:- Submitted by:-
Prof. Neelam wason Monika

GENERAL CONSIDERATIONS
Humans need a wide range of nutrients to lead a
healthy and active life. The required nutrients for
different physiological groups can only be derived
from a well balanced diet. Components of the diet
must be chosen judiciously to provide all the nutrients
to meet the human requirements in proper proportions
for the different physiological activities. The amount of
each nutrient needed for an individual depends upon
his/her age, body weight and physiological status.

There are certain general guidelines in arriving
at Nutrient Requirement and Dietary
Allowances for various groups. The nutrient
requirement of an individual and the dietary
allowances for a group or a population are
distinctly different. The former depends upon
the age, body weight and physiological and
metabolic status of the individual. The latter
must also take into consideration individual
variation within the group, quality of the diet,
effect of cooking and processing and bio-
availability of the nutrient from the diet.

Methods or approaches to assessing
nutritional requirement
Dietary intakes
Growth
Nutrient Balance
Factorial approach
Nutrient turnover
Depletion and repletion studies

NUTRIENT REQUIREMENT AND RECOMMENDED DIETARY
ALLOWANCES (RDA)
Recommended Dietary Allowance (RDA): the average
daily dietary nutrient intake level sufficient to meet the
nutrient requirement of nearly all (97 to 98 percent)
healthy individuals in a particular life stage and gender
group.
The RDA is derived from (i) the individual variability, and
(ii) the nutrient bio-availability from the habitual diet

Individual variability: Definition of RDA takes into
account the variability that exists in the
requirement of a given nutrient between
individuals in a given population group. The
distribution of nutrient requirement in a
population group is considered normal and the
RDA corresponds to a requirement, which covers
most of the individuals (97.5%) in a given
population. This corresponds to Mean + 2 SD. This is
termed as a safe level of intake of a nutrient, that is,
the chances of individuals having requirements
above the RDA is only 2.5%.

Bio-availability: Bio-availability of a
given nutrient from a diet, that is, the
release of the nutrient from the food,
its absorption in the intestine and bio
response have to be taken into
account. It is the level of the nutrient
that should be present in the diet to
meet the requirement.

ENERGY REQUIREMENTS INTRODUCTION
The body needs energy for maintaining body
temperature and metabolic activity and for
supporting physical work and growth. The energy
allowances recommended are designed to provide
enough energy to promote satisfactory growth in
infants and children and to maintain constant
appropriate body weight and good health in adults.
The factors which influence energy needs are age,
body size, physical activity and, in to some extent,
climate and altered physiological status such as
pregnancy and lactation.

The energy requirement of an
individual is defined as follows
The level of energy intake from food that
balances energy expenditure when the
individual has a body size and composition and
level of physical activity, consistent with long-
term good health, also allowing for
maintenance of economically essential and
socially desirable activity.

Recommended Dietary Allowance
 In practice ,a level of intake corresponding to mean + 2
Standard Deviations of the mean requirement which
covers 97.5% of the populations is chosen to define
RDA.
 This point must be kept in mind while applying RDA
at the individual level ,since for most individuals
(97.5%) RDA is higher than their actual minimal
requirement .

For the purpose of computing nutrient needs o population
at the national level, normal adult man and women are
defined.
Normal adult man is aged between 20-39 years with
normal weight 60 kg and height of 163 cm.
Normal adult woman is aged between 20-39 years with
normal weight of 50kg and height of 151 cm.
In case of children, body weights and heights of well
nourished healthy children with normal growth are used as
reference.
Who are Reference men and women

ENERGY REQUIREMENTS
The body needs energy for maintaining body
temperature and metabolic activity and for
supporting physical work and growth
To maintain energy balance, the input must equal
the output, which corresponds to a steady state
level of intake of an individual, at which he/she
remains in steady state or in energy balance,
maintaining predetermined levels of body weight
and physical activity, is considered to be the
individual‘s energy requirement.

Assessment of Energy Requirements
Current Approach :Currently, it is recommended
that energy requirement must be assessed in terms
of energy expenditure rather than in terms of
energy intake. Energy intake may vary from day to
day; on some days, it may be above the energy
expenditure and sometimes, below it. Body energy
reserves (viz., fat) help to maintain normal energy
expenditure over short periods even when the daily
intake is below expenditure.

Estimates of Energy Requirements
Adults – Energy requirement of adult is determined
from energy expenditure for basal metabolism and for
activity ,each contributing to approximately half of the
total daily energy expenditure .It is derived factorials
employing the activity break-up method .Energy
expended during sleep ,rest and occupational and
non-occupational activities during 24hrs are added up
to arrive at the total daily expenditure.
PAR = energy cost for individual activity per minute
energy cost for BMR per minute

A set of equations relating to body weight of adults and
their BMR was given by the 1985 recommendation of the
FAO/WHO/UNU (4.10). A study on BMR of Indian
subjects by Shetty and co-workers (4.18) indicated that
54
BMR of Indians is about 5% lower as compared to the
reported BMR in developed countries. Based on this
observation, a set of equations for computing basal
metabolism of Indian adults were proposed which were
used by ICMR Expert Group in 1989 (4.12). It is proposed
that the same set of equations as used by the previous
ICMR Expert Group (4.12) can be retained in the present
report.

Values for different categories of work for Indian reference adult
man and woman are given in Table along with values
recommended by FAO/WHO/UNU Consultation of 2002.

Energy Requirement during Pregnancy
In the Indian reference women with pre-pregnancy weight of
55 kg, the body weight gain may be 10 kg .
Additional energy needed for tissue deposition will be 85 kcal,
280 kcal and 470 kcal during the three trimesters if the body
weight gain is 12 kg. As is the practice, if only 2nd and 3rd
trimesters are taken into consideration, the average energy
requirement would be 375 kcal/day during that period. If the
body weight gain is only 10 kg and assuming body weight as
well as increase in body weight are assumed to have an
influence on PAL, increase in energy requirement during the
three trimesters would be 70 kcal, 230 kcal and 390 kcal or an
average of 310 kcal during the 2nd and 3rd trimesters

Energy cost of lactation
Energy cost of lactation is determined by the
breast milk output and its energy content
Daily additional energy requirement of a woman
doing exclusive breast feeding during the first 6
months would be 600 kcal and for partial breast
62
feeding during 7-12 months, it would be 517 kcal or
approximately 520 kcal.

Energy Requirement of Infant
and Children
It is impossible to measure accurately the activity of
infant and children ,energy requirement of these two
groups used to be derived from energy intakes of
healthy infant and children with normal growth
.Energy expenditure in children of different age groups
has been recently measured directly using doubly
labelled method.

Energy requirement of children
It has been found that the energy
requirement estimated is lower than the
value derived from food intake data from
children 1-10 years
in Indian children aged 8-9 years These
values are 1458 kcal/day and 1338 kcal/day in
boys and girls respectively.

Source of energy in Indian diets
 The main sources of energy in Indian diets, which are
predominantly plant food based, are carbohydrate, fat
and protein. The recent scientific update considers the
unhealthy role of simple sugars and recommends less
than 10% of total energy while recommending a wide
range of carbohydrate (55-75%) intake from whole
grains and legumes, vegetables and fruits.

Protein
Protein intake to maintain N equilibrium in adults and
a positive N balance in children to provide for growth
are used as criteria for estimating protein requirement.
The experimentally determined protein requirement
using N balance or other methods provides only the
average daily requirement .To arrive at the safe intakes
,mean (M) +2SD level ,is used. Since the coefficient of
variation between individuals ,estimated from N
balance data is 12.5% ,the mean requirement figure is
increased by 25% to arrive at the safe intakes.

Additional protein required during pregnancy and
lactation derived factorially .The suggested level of
protein intake in terms of protein energy ratio varies
from 7% in case of preschool children to 12% in case of
adolescents. For infant and children, the amino acid
requirement were found to be higher than those
predicted from balance data and correction for
digestibility with a poor quality diet resulted in higher
amounts of dietary protein required as compared to
the earlier recommendations.

Factorial method for arriving RDA
for proteins of Indians
 Basal or obligatory N loss
 The obligatory loss of urinary and faecal N has been
assessed by maintaining an individual on a protein-
free diet and estimating the faecal and urinary N
excretion.
 The directly observed obligatory N loss on a minimal
protein diet in Indians has been shown to be 20
mg/kg/d and 37mg/kg/d for faecal and urinary N
excretion respectively.

Total obligatory N loss for Indian adult subjects:
 Urinary 37 mg/kg/d
 Faecal 20 mg/kg/d
 Cutaneous 11 mg/kg/d
 Total 68 mg/kg/d = 0.4 g protein/kg/d

Based on N Balance
 the minimum dietary protein intake for N equilibrium
ranges from 0.5 to 0.66 g protein/kg/day with a mean
of 0.58 g/kg/day which after allowing for integumental
loss of 11 mg N/kg/day, works out to 0.65 g
protein/kg/day.
 daily safe level (estimated average requirement + 1.96
SD) of protein requirement of Indian adults on a cereal-
pulse-milk diet, adjusted for quality is about 1.0 g/kg/d,

Protein requirement during
pregnancy
 Protein requirement during pregnancy has been
assessed by the factorial method as the additional
requirement for foetal growth and expansion of
maternal tissue.
 This gave safe levels of additional protein of 1.2, 6.1 and
10.7 g/day in the first, second and third trimesters
respectively.

Protein Requirements during
Lactation
 During lactation, protein requirement has been
computed on the basis of secretion of 9.4 g per day of
protein in milk during 0-6 months and 6.6 g during 6-
24 months
 Rounded off figures for lactating women, additional
mean and safe protein intake at different months are
19 g/d for safe allowance for a lactating woman during
1-6 months and 13 g from 6 to 12 months.

Fat
Fat Requirement has to be is considered from the
point of view of total fat requirement and essential
fatty acid (EFA) requirement. Since excess dietary fat
(saturated) is harmful to health, recommendations of
fat intake include two values –optimum intake and
safe intake.
Dietary fats contribute mainly three type of fatty acid,
saturated (SAFA), Mono unsaturated (MUFA) and poly
unsaturated (PUFA).dietary fates should not be
present in amounts exceeding mono than roughly 30%
for long –term health.

The fat and the essential fatty acid (linoleic and linolenic
acids) in a diet can be derived from two sources; the
invisible fats which are present as one of the fixed
components in all common foods and the visible or the
added fat.
The desirable amounts of linoleic acid to be consumed by
adult and children is placed 4-10 en% (total dietary
energy). The requirement of EFA during pregnancy and
lactation is higher i.e. 4.5 and 6.0 en% respectively. The
requirement of linolenic acid (n-3) is only 0.6-2.3 en%.
Recent studies suggest that apart from total EFA content,
the ratio of n-6 (linoleic) to n-3 (linolenic) acids is also
important, the desirable ratio being 5-10 but not higher.
The recommendations of proposed (2008) RDA of fat are
given in table 1a along with the recommendations of the
1988 ICMR committee.

Minerals (macrominerals)
The macrominerals of calcium which are important in human nutrition
are calcium phosphorus, magnesium and electrolytes ,chloride
,sodium and potassium.
Calcium and phosphorus
The Requirement of calcium and phosphorus are considered together as
their occurrence, function and requirement are closely linked. Calcium
is a major element in the body and an adult man of 60kg has 1kg of Ca
most of which is present in the bones.
In growing children and infant Ca intake should ensure adequate Ca
retention for bone growth. Calcium requirement are measured by long-
term balance studies or turnover studies using labelled Ca or by
calcium accretion in bone after varying levels of ingestion . Absorption
of Ca was found to very between 20-25% in various groups based on the
dietary components .

Magnesium
Based on Mg balance studies at varying intakes, the
requirement of Mg were found to be 184 mg/d and thus 314
mg/d is considered safe intake in adult .
Sodium and potassium
Water metabolism is intimately connected with that of
sodium .Hypertension and diarrhoeal dehydration are the
states associated with excess ingestion and loss of sodium
respectively . Safe and adequate level of sodium is 1100-
3300 mg/d .The minimum requirement for a healthy
person is 500mg. As natural diet our country provides close
to 1g of NaCL , intake of cooking salt should be 5 or 6g/d to
prevent long-term consequences .About 50 mmol at lower
level and 140 mmol at the higher end of dietary intake are
considered to be safe.

Trace Elements -Microminerals
The following nine element are known to be essential for humans;
Iron, Zinc, Copper, Chromium, Cobalt, Manganess, Molybdenum and
selenium.
Iodine
The minimal requirement of iodine of adult of both sexes is
considered to be in the range of 50-75 µg/day.
Iron
Daily loss of body Iron in well - nourished adult men has been
estimated to be 12-15 µg/kg with an average of 14 µg/kg. This figure
was also used for determining the basal loss of body Iron in
women and children. The total Iron requirement of different
groups is computed factorially as follows;

 Adult man (Ref 60) Kg :Basal total loss of iron =14
µg/kg, absorption 5%,RDA= 17mg.
 Adult woman (Ref 50Kg); Basal loss + average mensst
rual loss of blood=30µg/kg
,Absorption 8%,RDA=19m
g
 Children ; Basal loss+ growth + expansion
of blood volume +improved iron stores =20µg/kg,
absorption 5%; Variable according to body weight
 Pregnant Woman ;Basal loss +foetal growth +
expansion of blood volume =60µg/kg, absorption 8% ,RDA
=37.5
 Lactating Woman ;Basal loss + loss through breast
milk =30µg/kg. 8%, RDA =19 mg

Vitamins
Fat Soluble Vitamins
 Vitamin A; The minimum level of vitamin A
required to reverse completely dark adaptation
failure and abnormal retinogram along with adequate
stores is established as 600µg/day or 9.3 µg/kg. this
level of intake has been shown to maintain the
serum level of retinol at 20µg/dl.
The recommended intake of Vitamin A (retinol) of
Indian adult is 600µg/day based on 9.3 µg/kg body
weight.

The requirement of Indian pregnant women was
found to be 750µg/d. Additional intake of 350
µg/day is suggested during lactation to compensate
for the loss of Vitamin through breast milk. The
Vitamin A requirement in early infancy is 50µg/kg
based on the retinol content of breast milk of well-
nourished mothers. This value declines gradually to
9.3µg/kg in adult. The requirement of children is
proportional to their growth rates.

Vitamin D
 Vitamin D requirement of Indians are considered to be met
entirely by exposure to sunlight. In the absence of exposure
to sunlight a daily intake of 400 IU Vitamin D is suggested.
Vitamin E and K
 Vitamin a requirement is related to its protective
antioxidant property on their essential fatty acid
content of the diet and the suggested intake is 0.8 mg
per g of EFA. FAO consultancy suggested RDA of 7.5
mg α-tocopherol and 55µg Vitamin k/d for adult. Data
on Vitamin K content of India n foods have not yet
been generated.

Water soluble Vitamins
 Vitamin C; minimum daily intake of ascorbic acid to
cure scurvy is as low 6.5 mg. The daily intake of Vitamin C
has been fixed at 40 mg by the previous ICMR committee
based on the presumption that 50% of ascorbic acid may
lost on cooking or storage of food rich in Vitamin C.
 B-complex Vitamins
 The Vitamins which are included under this group are
thiamine (B1), riboflavin (B2), niacin, pyridoxine (B6),
Folate and Vitamin B12, since deficiencies of all of them are
encountered in human populations.
 Since thiamine riboflavin and niacin are involved in energy
metabolism; their requirements have been related to
energy requirement and expressed as mg per 1000 Kgcals.

Thiamine , Riboflavin, Niacin
 The human requirement of these three B-Vitamins;
erythrocyte transketolase levels I n case of thiamine
,erythrocyte, glutathione reductase level in the case of
riboflavin ,
 the minimal quantity required for curing pellagra or
maintaining urinary excretion of the Vitamin in the
case of niacin.

 The human requirement of Vitamin B6 has adult requirement appears
to be about 2.0 mg/day.
 Folate and Vitamin B12
 The requirements of both folate and Vitamin B12 have
been assessed on the basis of the minimum amount
required to bring about heamatological response in
deficient subjects suffering fore megaloblastic anaemia.
Based on the these studies the daily minimal requirement
to free folic acid has been set as 75µg.

Requirement for nutrients

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