Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set
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food is then reduced to the appropriate particle size,
and hot-filled into cans or jars which are then sealed.
The cans or jars are then heat-treated in pressure
cookers, using a temperature–time–pressure regime,
depending upon the type of product being processed.
Finally the cans or jars are cooled and then labeled.
0066 Ready-to-feed weaning foods in cans or jars do not
need further cooking at home, and can be safely fed to
infants without heating them up. If it is desired to heat
the food, the required amount should be removed
from the can or jar and placed in a clean cup or
small bowl. This should be stood in a saucepan or
bowl of hot water and covered. The food becomes
lukewarm and ready to serve in a few minutes. The
food should be stirred and the temperature tested
with another spoon before feeding.
0067Any remaining unwarmed food should be re-
moved from the can or jar, placed in a clean
container, covered and stored in the refrigerator for
up to 48 h.
tbl0001 Table 1 Composition of processed cereal-based foods for infants and young children: requirements of European Union legislation
a
Type of product Compositionalrequirements
Simple cereals which are or have to be
reconstituted with milk or other
appropriate nutritious liquids
Carbohydrate: the amount of added carbohydrate from sucrose, fructose, or glucose
shall not exceed 1.8 g 100 kJ
1
(7.5 g 100 kcal
1
). The amount of added fructose
shall not exceed 0.9 g 100 kJ
1
(3.75 g 100 kcal
1
)
Fat: content shall not exceed 0.8 g 100 kJ
1
(3.3 g 100 kcal
1
)
Sodium: content may not exceed 25 mg 100 kJ
1
(100 mg 100 kcal
1
)
Thiamin: content shall not be less than 25 mg 100 kJ
1
(100 mg 100 kcal
1
)
Vitamin A: if added, vitamin A content shall be a minimum of 14 mg RE 100 kJ
1
(60 mg RE 100 kcal
1
) and a maximum of 43 mg RE 100 kJ
1
(180 mg RE 100 kcal
1
)
Vitamin D: if added, vitamin D content shall be a minimum of 0.25 mg 100 kJ
1
(1 mg 100 kcal
1
) and a maximum of 0.75 mg 100 kJ
1
(3 mg 100 kcal
1
)
Cereals with an added high-protein food
which are or have to be reconstituted with
water or other protein-free liquid
Protein: content shall not exceed 1.3 g 100 kJ
1
(5.5 g 100 kcal
1
). The added protein
shall not be less than 0.48 g 100 kJ
1
(2 g 100 kcal
1
). There is an additional
requirement to insure high quality of the added protein
Carbohydrate: the amount of added carbohydrate from sucrose, fructose, or glucose
shall not exceed 1.2 g 100 kJ
1
(5 g 100 kcal
1
). The amount of added fructose shall
not exceed 0.6 g 100 kJ
1
(2.5 g 100 kcal
1
)
Fat: content shall not exceed 1.1 g 100 kJ
1
(4.5 g 100 kcal
1
)
Sodium: content may not exceed 25 mg 100 kJ
1
(100 mg 100 kcal
1
)
Calcium: shall not be less than 20 mg 100 kJ
1
(80 mg 100 kcal
1
)
Thiamin: content shall not be less than 25 mg 100 kJ
1
(100 mg 100 kcal
1
)
Vitamin A: content shall be a minimum of 14 mg RE 100 kJ
1
(60 mg RE 100 kcal
1
) and
a maximum of 43 mg RE 100 kJ
1
(180 mg RE 100 kcal
1
Vitamin D: content shall be a minimum of 0.25 mg 100 kJ
1
(1 mg 100 kcal
1
) and a
maximum of 0.75 mg 100 kJ
1
(3 mg 100 kcal
1
)
Pastas which are to be used after cooking
in boiling water or other appropriate
liquids
Sodium: content may not exceed 25 mg 100 kJ
1
(100 mg 100 kcal
1
)
Thiamin: content shall not be less than 25 mg 100 kJ
1
(100 mg 100 kcal
1
)
Vitamin A: if added, vitamin A content shall be a minimum of 14 mg RE 100 kJ
1
(60 mg RE 100 kcal
1
) and a maximum of 43 mg RE 100 kJ
1
(180 mg RE 100 kcal
1
)
Vitamin D: if added, vitamin D content shall be a minimum of 0.25 mg 100 kJ
1
(1 mg 100 kcal
1
) and a maximum of 0.75 mg 100 kJ
1
(3 mg 100 kcal
1
)
Rusks and biscuits which are to be used
either directly or, after pulverization, with
the addition of water, milk, or other suitable
liquids
Protein: protein content shall not exceed 1.3 g 100 kJ
1
(5.5 g 100 kcal
1
). For biscuits
made with the addition of a high-protein food, and presented as such, the added
protein shall not be less than 0.36 g 100 kJ
1
(1.5 g 100 kcal
1
). There is an
additional requirement to insure high quality of the added protein
Carbohydrate: the amount of added carbohydrate from sucrose, fructose, or glucose
shall not exceed 1.8 g 100 kJ
1
(7.5 g 100 kcal
1
). The amount of added fructose
shall not exceed 0.9 g 100 kJ
1
(3.75 g 100 kcal
1
)
Fat: content shall not exceed 0.8 g 100 kJ
1
(3.3 g 100 kcal
1
)
Sodium: content may not exceed 25 mg 100 kJ
1
(100 mg 100 kcal
1
)
Calcium: for products manufactured with the addition of milk, and presented as such,
the amount of calcium shall not be less than 12 mg 100 kJ
1
(50 mg 100 kcal
1
)
Thiamin: content shall not be less than 25 mg 100 kJ
1
(100 mg 100 kcal
1
)
Vitamin A: if added, vitamin A content shall be a minimum of 14 mg RE 100 kJ
1
(60 mg RE 100 kcal
1
) and a maximum of 43 mg RE 100 kJ
1
(180 mg RE 100 kcal
1
)
Vitamin D: if added, vitamin D content shall be a minimum of 0.25 mg 100 kJ
1
(1 mg 100 kcal
1
) and a maximum of 0.75 mg 100 kJ
1
(3 mg 100 kcal
1
)
a
Commission Directive 96/5/EC, as amended.
The amount of cereal and/or starchy root shall not be less than 25% of the final mixture on a dry weight-for-weight basis. RE, retinol equivalents.
3280 INFANT FOODS/Weaning Foods
tbl0002 Table 2 Composition of baby foods for infants and young children: requirements of European Union legislation
a
Type of product Compositionalrequirements
Meat, fish, or other traditional source of
protein are the only ingredients
mentioned in the name of the product
Protein: The named meat, fish, or other traditional source of protein shall constitute not
less than 40% by weight of the product
Each named meat, fish, or other traditional source of protein shall constitute not less
than 25% by weight of the total named protein sources
Protein from the named sources shall not be less than 1.7 g 100 kJ
1
(7 g 100 kcal
1
)
Fat: If meat or cheese are the only ingredients mentioned in the name of the product, or
are mentioned first, total fat content should not exceed 1.4 g 100 kJ
1
(6 g 100 kcal
1
)
Sodium: If cheese is the only ingredient mentioned in the name of the product, sodium
content shall not be more than 70 mg 100 kJ
1
(300 mg 100 kcal
1
).
For other products, sodium content should be either not more than 48 mg 100 kJ
1
(200 mg 100 kcal
1
) or not more than 200 mg 100 g
1
Vitamin A and vitamin D: may not be added
Meat, fish, or other traditional source of
protein is mentioned first in the name
of the product
Protein: The named meat, fish, or other traditional source of protein shall constitute not
less than 10% by weight of the product
Each named meat, fish, or other traditional source of protein shall constitute not less
than 25% by weight of the total named protein sources
Protein from the named sources shall not be less than 1 g 100 kJ
1
(4 g 100 kcal
1
)
Fat: Content should not exceed 1.1 g 100 kJ
1
(4.5 g 100 kcal
1
)
Sodium: Content should be either not more than 48 mg 100 kJ
1
(200 mg 100 kcal
1
)or
not more than 200 mg 100 g
1
Vitamin A and vitamin D: may not be added
Meat, fish, or other traditional source of
protein is mentioned, but not first, in the
name of the product
Protein: The named meat, fish, or other traditional source of protein shall constitute not
less than 8% by weight of the product
Each named meat, fish, or other traditional source of protein shall constitute not less
than 25% by weight of the total named protein sources
Protein from the named sources shall not be less than 0.5 g 100 kJ
1
(2.2 g 100 kcal
1
)
Total protein shall not be less than 0.7 g 100 kJ
1
(3 g 100 kcal
1
)
If cheese is mentioned in the name, protein from dairy sources shall not be less than
0.5 g 100 kJ
1
(2.2 g 100 kcal
1
); total protein shall not be less than 0.7 g 100 kJ
1
(3 g 100 kcal
1
)
Fat: Content should not exceed 1.1 g 100 kJ
1
(4.5 g 100 kcal
1
)
Sodium: Content should be either not more than 48 mg 100 kJ
1
(200 mg 100 kcal
1
)or
not more than 200 mg 100 g
1
Vitamin A and vitamin D: May not be added
Product is designated as a meal, but meat,
fish, or other traditional source of protein
not mentioned in the product name
Protein: Total protein shall not be less than 0.7 g 100 kJ
1
(3 g 100 kcal
1
)
Fat: Content should not exceed 1.1 g 100 kJ
1
(4.5 g 100 kcal
1
)
Sodium: Content should be either not more than 48 mg 100 kJ
1
(200 mg 100 kcal
1
)or
not more than 200 mg 100 g
1
Vitamin A and vitamin D: May not be added
Fruit-only dishes Carbohydrate: Shall not exceed 20 g 100 g
1
Fat: Content should not exceed 1.1 g 100 kJ
1
(4.5 g 100 kcal
1
)
Sodium: Content should be either not more than 48 mg 100 kJ
1
(200 mg 100 kcal
1
)or
not more than 200 mg 100 g
1
Vitamin A and vitamin D: May not be added
Desserts and puddings Protein: If a dairy product is the first or only ingredient mentioned in the product name,
protein from dairy sources must be at least 0.5 g 100 kJ
1
(2.2 g 100 kcal
1
)
Carbohydrate: Shall not exceed 25 g 100 g
1
Fat: Content should not exceed 1.1 g 100 kJ
1
(4.5 g 100 kcal
1
)
Sodium: Content should be either not more than 48 mg 100 kJ
1
(200 mg 100 kcal
1
)or
not more than 200 mg 100 g
1
Drinks Carbohydrate: Vegetable juices and drinks based on them: shall not exceed
10 g 100 ml
1
Fruit juices, nectars and drinks based on them: shall not exceed 15 g 100 ml
1
Other nonmilk-based drinks: shall not exceed 5 g 100 g
1
Fat: Content should not exceed 1.1 g 100 kJ
1
(4.5 g 100 kcal
1
)
Vitamin C: Fruit/vegetable juices – content should be at least 6 mg 100 kJ
1
(25 mg 100 kcal
1
) or at least 25 mg 100 g
1
Vitamin A: Vegetable juices – content should be at least 25 mg RE 100 kJ
1
(100 mg RE 100 kcal
1
). May not be added to other foods
Vitamin D: May not be added
a
Commission Directive 96/5/EC, as amended. RE, retinol equivalents.
INFANT FOODS/Weaning Foods 3281
Homemade Weaning Foods
0068 Preparing weaning foods at home is largely a matter
of adapting normal cooking processes. If a meal is
being cooked for other members of the family, it is
usually possible for a suitable weaning food to be
prepared from the same basic ingredients.
0069 Preparation of homemade weaning foods usually
involves omission of certain ingredients, such as chilli
peppers, garlic, ginger, and other spicy ingredients,
which might irritate the infant’s digestive tract. Salt
should not be added during cooking.
0070 Grilling, baking, poaching, or boiling are all suit-
able cooking methods, but frying with added fat is
not recommended. When the food has been cooked, it
is necessary to reduce it to a suitable consistency,
according to the infant’s stage of development. Many
hand and electrical gadgets are available for this
purpose.
0071 Using a microwave oven is not recommended to
heat foods for infants as microwaves can cause
uneven heating and food could burn an infant’s
mouth. However, if a microwave is used to heat
foods for infants, the manufacturer’s instructions
must be followed exactly. The food should always
be stirred to insure an even distribution of heat and
the temperature checked before the food is fed to an
infant.
Weaning Foods in Developing Countries
0072 The first foods added to the diet are generally staple
foods. These might include cereals and tubers such as
maize, rice, millet, or sweet potato. In China, the
staple of the diet is rice, whereas semolina is used in
India. In Kenya, the infant diet is based on maize and
in Nepal on soya, wheat, and maize.
0073 The simplest recipe for weaning foods is one which
has only two ingredients, for example a cereal or root
mixed with a legume. Other foods can be added to
this basic mix to make a complete meal. Such recipes
are known as multimixes and consist of four basic
ingredients:
1.
0074A staple as the main ingredient – preferably a cereal.
2.
0075A protein supplement from a plant or animal food
– beans, groundnuts, meat, milk, chicken, fish,
eggs, etc.
3.
0076A vitamin and mineral supplement – a vegetable
and/or fruit.
4.
0077An energy supplement – fat, oil, or sugar to
increase the energy concentration of the mix.
Hygiene
0078Since infants are particularly susceptible to infection
during the first year of life, special care must be taken
to avoid introducing a source of infection via weaning
foods. The scrupulous washing of hands and all
equipment used in the home preparation of food is
essential. Plastic or glass items, such as plates, spoons,
and mugs, can be sterilized chemically, but metal
utensils must be boiled.
0079All weaning food manufacturers have very strict
specifications to insure the safety of their products.
Cleanliness is maintained in the manufacturing envir-
onment with rigorous standards of hygiene.
See also: Infants: Nutritional Requirements; Weaning
Further Reading
Commission directive 96/5/EC (1996) Processed cereal-
based foods and baby foods for infants and young chil-
dren. Official Journal of the European Communities
L49: 17–28.
Commission directive 98/36/EC (1998) Amending directive
96/5/EC on processed cereal-based foods and baby foods
for infants and young children. Official Journal of the
European Communities L167: 23–24.
Department of Health (1999) Committee on Toxicity of
Chemicals in Food, Consumer Products and the Envir-
onment. Peanut Allergy. London: Department of Health.
Department of Health (1994) Report on Health and Social
Subjects No. 45. Weaning and the Weaning Diet.
London: HMSO.
Mills A and Tyler H (1992) Food and Nutrient Intakes of
British Infants Aged 6–12 Months. London: HMSO.
3282 INFANT FOODS/Weaning Foods
INFANTS
Contents
Nutritional Requirements
Breast- and Bottle-feeding
Weaning
Feeding Problems
Nutritional Requirements
J Morgan, University of Surrey, Guildford, Surrey, UK
Copyright 2003, Elsevier Science Ltd. All Rights Reserved.
Introduction
0001 For the purposes of this article, infants are defined as
aged from birth to 12 months.
0002 For many years estimating energy and nutrient
requirements in infancy has relied on data derived
from feeding studies and growth patterns of healthy
full-term wholly breast-fed infants. Thus require-
ments in infancy were based on food intake data.
However, more direct evidence for requirements (for
example, energy expenditure data) has provided more
direct data on needs. Thus, recent national and inter-
national committees have reflected this knowledge
when proposing the best estimate of infant nutrient
requirements and reference intakes.
Individual Variation in Food Intake
0003 The wide individual variation in energy and nutrient
intakes at any age has been recognized for 40 years.
At 1 year of age there are infants at the upper end of
the range consuming twice as much food as those at
the lower end – some infants at 6 months are consum-
ing energy intakes equivalent to those of young
women (Table 1). The phenomenon of the variation
in food intake (and hence nutrient requirement) high-
lights the need to distinguish between the terms
‘requirement’ and ‘recommended intake.’
0004The effect of gender is well recognized: On average,
boys have a greater intake of energy than girls. The
US Recommended Dietary Allowances report (1989)
provides an average energy allowance (AEA) for
energy requirements from birth to 10 years which
does not distinguish between sexes for energy require-
ments. However, other authorities, such as the UK
Department of Health, do distinguish between the
sexes with regard to energy requirements.
0005In young infants the nutrient requirement for
growth itself is substantial, representing up to 30%
of the energy requirement, but there exists a large
variation within the normal range on the rate of
growth and probably also in the composition of the
tissue laid down.
0006The ‘average’ composition of human milk has been
used as a basis for estimating requirements and also
for calculating the composition of infant milk formu-
lae. It is as well to remember, however, that the com-
position of human milk varies, from mother to
mother, and from day to day. It depends on the stage
of lactation and on the mother’s diet (particularly the
content of polyunsaturated fatty acids). As well as
providing nutritional substances, milk contains sev-
eral growth factors, including epidermal growth
factors, insulin, and insulin-like growth factor (IGF-
1). The physiological importance of these substances
has not yet been established.
tbl0001 Table 1 Energy intake of boys and girls, illustrating average intake and maximum and minimum values
Age group (years) Average (kcal/kJ day
1
) Maximum (kcal/kJ day
1
) Minimum (kcal/kJ day
1
)
Boys 1 1154/4824 1547/6466 811/3390
2 1406/5877 1929/8063 959/4009
3 1691/7068 2340/9781 1250/5225
Girls 1 1152/4815 1631/6818 842/3520
2 1431/5982 2048/8561 1055/4410
3 1533/6408 2328/9731 991/4142
Calculated from Widdowson EM (1947) A Study of Individual Children’s Diets. London: Medical Research Council/HMSO.
INFANTS/Nutritional Requirements 3283
Requirement for Energy
000 7 Recently, recommendations for energy have been
given as the estimated average energy requirement
(EAR) – about half the population will usually need
more than the EAR and half less. A recommendation
for an energy intake that is adequate for all infants
could result in obesity in those infants who have
lower than average requirements, therefore the EAR
reflects the estimated average energy requirement.
0008 Energy requirements for infancy should be esti-
mated from data on energy expenditure. The 1985
World Health Organization (WHO) / Food and Agri-
culture Organization report on energy requirements
in humans based its recommendations for infants on
the observed intake of healthy infants growing nor-
mally. It is recognized, however, that observed and
desired energy intake may differ, and that a better
estimate of energy needs is provided by energy ex-
penditure. The available database on energy expend-
iture in infants has greatly expanded since 1985,
thanks in large part to the application of the doubly-
labeled water technique. This noninvasive method
permits a reliable quantification of total daily
expenditure in infants under normal conditions of
everyday life. There are now thousands of data points
on energy expenditure in infants obtained with this
method. In addition, new data on growth and energy
intake of exclusively breast-fed infants became avail-
able. Taken together, these data on intake, growth,
and energy expenditure suggest that the actual energy
requirements for breast-fed infants may be 10–40%
lower than the 1985 estimates. One explanation for
the overestimation of the previous recommendation
may be first, that the data set of observed intakes
included a large proportion of formula-fed infants,
who consume higher amounts of energy than breast-
fed infants, and second, that the reference standard
for desirable growth is also based largely on a popu-
lation of predominantly formula-fed infants.
0009The fact that healthy, exclusively breast-fed infants
grow at a slower rate than the current reference
standards is the subject of ongoing research. There
is evidence, however, that these infants are no differ-
ent than infants consuming more energy and growing
at a faster rate in terms of morbidity, sleep patterns,
or physical activity.
0010As a result of these studies, efforts are under way to
develop a growth reference chart for exclusively
breast-fed infants, which presumably would reflect
a more physiological growth pattern than that of
formula-fed infants.
0011Dietary reference values (DRV) for infants (males
and females) from reports published under the aus-
pices of UK, USA, and European committees are
given in Table 2.
Requirement for Protein
0012Estimates of protein requirements for young infants
are based on milk intake data. The WHO, the
National Research Council, and the Department of
Health have utilized this method.
0013Table 3 shows the reported intake of protein in
human milk-fed male and female babies between
birth and 4 months. Assumptions have been made
regarding the protein content of milk (and comple-
mentary foods after 4 months) and the figure of 1.15 g
of protein per 100 ml (for milk) is generally accepted.
Because of the high quality and easy digestibility of
human milk protein, few infants fed human milk
develop protein deficiency.
0014In estimating protein requirements from 6 to 12
months, the WHO Committee used the factorial ap-
proach. A gray area of knowledge exists for protein
requirements between 4 and 6 months of age. Esti-
mates of protein requirements have been extrapolated
from energy requirements, i.e., 1040 ml of breast milk
per day is needed to fulfill the theoretical energy
needs, and hence protein requirements, of male
tbl0002 Table 2 Dietary reference values for energy for males and females
Age
(years)
UK
EAR (kcal/MJ day
1
)
USA
AEA (kcal/MJ day
1
)
EU
EAR (kcal/MJ day
1
)
Males
0–3 545/2.28 650/2.7 550/2.3
4–6 690/2.89 650/2.7 715/3.0
7–9 825/3.44 850/3.5 850/3.5
10–12 920/3.85 850/3.5 930/3.9
Females
0–3 515/2.16 650/2.7 500/2.1
4–6 645/2.69 650/2.7 670/2.8
7–9 765/3.20 850/3.5 790/3.3
10–12 865/3.61 850/3.5 885/3.7
EAR, estimated average requirement; AEA, average energy allowance.
3284 INFANTS/Nutritional Requirements
infants aged 5–6 months. This approach is obviously
not ideal.
001 5 Table 4 outlines the dietary reference values for
protein (g day
1
) for the period 0–12 months from
various reports. A major point of issue when estimat-
ing requirements is the variation in protein needs for
growth. The uncertainty related to this factor has
resulted in the addition of 50% to the theoretical
nitrogen accretion in the calculation of protein
requirements. In fact, adjustment by 50% may even
be too small. This is obviously an area where research
is urgently needed, i.e., to investigate the daily vari-
ation in growth rate and the constraints in storage of
essential amino acids to be available when maximum
growth occurs. To adjust for interindividual variation
in growth and maintenance, a factor of 12.5% has
been incorporated. A theoretical basis for calculating
the variability of protein requirement for growth does
not exist. Work by Fomon indicates that over a period
of 1 month children vary in their average daily rate of
growth, with a coefficient of variation of 37%. This
variation in weight gain is much greater than the
variability in protein intake.
001 6 Human milk contains characteristic nitrogen-con-
taining components. In fact, 25% of the nitrogen is
derived from nonprotein sources: free amino acids,
small peptides, amino sugars, creatine, creatinine,
and glycolipids. The content of free taurine is 30–40
times higher in human milk compared with cows’
milk. Although the nutritional or biochemical role
of some of these substances is not fully understood,
their presence, like that of the growth-promoting
factors previously mentioned, should not be dis-
missed.
0017The specific amino acid requirements of infants are
of interest. It appears that, beside the eight essential
amino acids, three other amino acids (cysteine, taur-
ine, and histidine) are essential in the postnatal
period. This has implications for one aspect of infant
feeding – the provision of total nutrition by intraven-
ous (IV) feeding. Only recently have amino acid prep-
arations for IV nutrition been tailored to the
requirements of infants, including an appropriate
amino acid profile.
Requirements for Fats
0018In the broadest sense, infants have a requirement for
fats to provide energy, to provide essential fatty acids,
to facilitate the absorption of the fat-soluble vitamins
A, E, and D, and as a precursor of structural lipids
and eicosanoids. Triacylglycerols in human milk con-
tain more than 150 different fatty acids, but the origin
and role of many of these are largely unknown. The
average intake of fat can be calculated for breast-fed
infants if the fat content of the breast milk is known
(Table 5).
0019The specific requirements of long-chain polyunsat-
urated fatty acids (PUFA) and cholesterol in infants
are not often considered. Infants have specific re-
quirements for PUFA. In the 1950s and 1970s there
were reports of deficiency in long-chain fatty acids in
premature infants fed parenterally with no lipid
source, and in full-term infants fed on formula devoid
of linoleic acid. Human milk contains on average
7.2 g of linoleic acid per 100 g total fatty acids or
285 mg per 100 ml, i.e., 3.7% of total energy. The
DRV report panel recommended that for infants and
young children: ‘linoleic acid should provide at least
1 per cent of total energy and alpha linolenic acid at
least 0.2 per cent of total energy.’
tbl0003 Table 3 Average daily intake of protein by breast-fed infants,
0–4 months
Age (months) Boys (g/kg day
1
)Girls(g/kgday
1
)
0–1 2.46 2.39
1–2 1.93 1.93
2–3 1.74 1.78
3–4 1.49 1.53
Modified from World Health Organization (1985) Energy and Protein
Requirements. WHO Technical Report Series no. 522 and FAO Nutrition
Meeting Report Series no. 724.
tbl0004 Table 4 Dietary reference values for protein
UK USA EU
Age RNI RDA PRI
(years) (g day
1
)(gday
1
)(gday
1
)
0–3 12.5
a
13.0
4–6 12.7 13.0 14.0
7–9 13.7 14.0 14.5
10–12 14.9 14.0 14.5
RNI, reference nutrient intake; RDA, recommended dietary allowance;
PRI, population reference intake.
a
Based on egg and milk protein: assume complete digestibility.
tbl0005Table 5 Average daily intake of fat by breast-fed infants aged
0–4 months
Age Breast milk Weight
Average fat intake
a
(months) consumed (ml) (kg) (g) (g/kgday
1
)
Boys
0–1 719 3.8 30 8
1–2 795 4.75 33 7
2–3 848 5.6 36 6
3–4 822 6.35 35 5
Girls
0–1 661 3.6 28 8
1–2 731 4.35 30 7
2–3 780 5.05 32 6
3–4 756 5.7 32 5
a
Fat content of breast milk 4.2 g per 100 ml.
INFANTS/Nutritional Requirements 3285
0020 Human milk is relatively rich in cholesterol, pro-
viding an average 16 mg l
1
. The existence of this
sterol in breast milk is indicative of a biological role,
although no authority to date has made recommen-
dations on desirable intakes in infants not receiving
human milk.
0021 Several studies have suggested a specific role for
certain PUFA in visual development. Eicosapentaenoic
acid and docosapentaenoic acid have been evaluated in
term and preterm infants; these fatty acids are found in
high concentration in human milk, but they have not
been added to infant formulae until recently. The re-
quirement for them may be higher in preterm infants,
but their contribution to visual development of the full-
term healthy infant is not fully documented at this
point. Several commercial infant formulae, however,
are now fortified with eicosapentaenoic acid.
Requirement for Carbohydrate
002 2 Eighty percent of the total carbohydrate in human
milk is a sugar, lactose (approximately 7g per
100 ml of human milk). In early infancy, when the
diet consists wholly of milk, about 40% of the energy
intake is derived from lactose.
0023 As the diet of the infant becomes more varied, the
carbohydrate content also varies. Table 6 provides
detailed information on the carbohydrate contribution
of foods given to infants. After about 4–6 months
human milk or infant milk formulae alone cannot
meet an infant’s energy and other nutrient require-
ments (notably iron). It is important to remember that
infants are not miniature adults and that they have
their own specific nutrient needs. There is evidence,
however, that dietary guidelines for adults are being
inappropriately applied to infants. There is a particu-
lar concern regarding the provision of nonstarch
polysaccharides (NSP) and also the use of low-fat
products in the diet of young children. The UK
panel recommended in 1991 that children should
have proportionally lower NSP intakes than adults,
and that consumption should not be at the expense of
energy-rich foods. However, no specific guidelines
were given regarding safe intakes for NSP for infants.
Requirement for Vitamins and Minerals
0024In the UK, supplementation of vitamins is recom-
mended for breast-fed infants and young children
from 6 months to 5 years unless the child’s diet is
diverse and plentiful. The daily dose of five vitamin
drops provides 7 mg of vitamin D, 200 mg of vitamin
A, and 20 mg of vitamin C.
Requirement for Vitamin A
0025Dietary requirements for vitamin A in infants have
been usually based on and extrapolated from intakes
calculated from values obtained from a wholly
breast-fed infant receiving milk from a well-nour-
ished mother. The breast milk from women living in
the USA and Europe contains 40–70 mg of retinol per
100 ml milk and between 20 and 40 mg of carotenoids
per 100 ml of milk. Assuming milk is consumed at
750 ml per day (and the concentration of retinol is
40 mg per 100 ml), the infant would receive about
300 mg of retinol per day. After taking into account
factors such as individual variation in retinol content
of milk, the US committee (NRC 1989) recommend
an intake of 350 mg day
1
up to 1 year. The UK
recommendations (DoH 1991) are set at 350 mgof
retinol equivalents per day. In developing countries,
vitamin A deficiency is uncommon in the first year of
life. A drastic fall in the vitamin A content of milk has
to be preceded by the exhaustion of the mother’s
stores of this vitamin.
Requirement for Vitamin D
0026Only small amounts of vitamin D are secreted in
human breast milk, which indicates that a dietary
source of this substance is teleologically unimportant;
the major source of vitamin D is the action of ultra-
violet (UV) light on the skin. The amount of exposure
to UV light will differ from infant to infant. Because
of this uncertainty, and to safeguard against lack of
exposure to sunlight in the UK, the reference nutrient
intake (RNI) is 8.5 mg of vitamin D per day (from
food or supplements) from 0 to 6 months, and 7 mg
day
1
from 7 to 12 months. The US recommended
dietary allowance (RDA) is set at 7.5 mg day
1
for
infants from birth to 6 months of age, and 10 mg
day
1
from 6 months onwards because of increased
body mass. The European ‘safe range’ from 0 to 3
years is 10–25 mg day
1
.
0027Thus, three authorities recommend a target intake
for vitamin D, although there is no doubt that healthy,
tbl0006 Table 6 Average carbohydrate content of several foods for
infants
Carbohydrate
Food (% energy)
Human milk 37
Cows’ milk 29
Strained meat 1
Strained fruits 96
Strained desserts 89
Strained vegetables 80
Strained soups and dinners 56
Strained high-meat dinners 29
Data from Fomon SJ (1974) Infant Nutrition, 2nd edn. Philadelphia: WB
Saunders.
3286 INFANTS/Nutritional Requirements
wholly breast-fed infants who are exposed to sunlight
do not require oral supplementation. Vitamin D defi-
ciency in the material diet, lack of sunlight, adverse
social or environmental factors, and infant prematurity
indicate the need for supplementation.
0028 Excessive intake of vitamin D is potentially harm-
ful: only five times the RNI (45 mg day
1
) has been
reported to be associated with hypervitaminosis in
young children.
Requirement for Ascorbic Acid (Vitamin C)
0029 Scurvy occurs primarily in infants fed diets consisting
exclusively of cows’ milk; as this mode of feeding is
very uncommon, scurvy is rare in infants under 1 year
of age. There are reports that infants receiving as little
as 7 mg of vitamin C per day are protected from
scurvy. Human milk contains approximately 4 mg of
vitamin C (ascorbic acid and dehydroascorbic acid)
per 100 ml. An infant receiving 750 ml of human milk
per day will receive in the order of 30 mg of vitamin C.
The UK recommends a daily intake of 25 mg of vita-
min C up to 12 months; the USA recommends a daily
intake of 30 mg and 35 mg of vitamin C from 0 to 6
months and 7 months to 1 year of age respectively.
Requirement for Iron
0030 A normal healthy fetus stores iron in the last trimester
of pregnancy. Because of this, a full-term infant can
maintain satisfactory hemoglobin levels, without any
other sources of iron, for about the first 4–6 months
of life. Breast milk is noticeably low in iron – 76 mg
100 ml
1
. However, because the iron is well absorbed
(50–70%, compared with 10–30% from cows’ milk),
and because an infant has hepatic hemoglobin stores,
a dietary source is unnecessary. After 4–6 months of
age, and in nonbreast-fed infants from birth, a dietary
iron source is needed. Infant milk formulae and many
infant food products contain added iron, thus insur-
ing an appropriate dietary intake; in addition food
commodities such as red meat can be included to
provide a source of bioavailable iron. Dietary refer-
ence values for iron differ from country to country. At
ages 4–6 months the UK value is 4.3 mg day
1
, the
USA RDA is 6.0 mg day
1
, and the WHO recommen-
dation is 8.5 mg day
1
.
Requirement for Calcium
0031 Adequate mineralization of the skeleton occurs in
breast-fed infants receiving an intake of calcium as
low as 200–300 mg day
1
. The most important factor
governing calcium absorption is the degree of skeletal
mineralization, mediated by a feedback mechanism,
controlled by synthesis of 1,25-dihydroxycholecalci-
ferol (a derivative of vitamin D). Others factors in-
clude a high dietary lactose content, the composition
and structure of dietary fat, and a low buffering effect
– all provided by human milk. Approximately 66%
of calcium intake is absorbed. Although the require-
ment of calcium is probably 250 mg day
1
, the rec-
ommended intake is usually set in the region of
500 mg day
1
. The safety margin is necessary to allow
for a variance in the absorption rate and to allow for
individual variation in requirement.
Conclusion
0032An infant is not a small adult. During the first year of
life, in particular, the infant has specific requirements
related to physiology. As these requirements are be-
coming more fully understood, so more completely
are we able to meet the requirement by adjusting
infant milk formula. There are still gaps in our
knowledge and these have been highlighted.
See also: Amino Acids: Metabolism; Ascorbic Acid:
Physiology; Calcium: Physiology; Carbohydrates:
Requirements and Dietary Importance; Energy: Intake
and Energy Requirements; Measurement of Energy
Expenditure; Energy Expenditure and Energy Balance;
Growth and Development; Infant Foods: Milk
Formulas; Weaning Foods; Iron: Physiology; Lactation:
Physiology; Protein: Requirements; Retinol: Physiology
Further Reading
Butte N (1996) Energy requirements of infants. European
Journal of Clinical Nutrition 50: S24–S36.
Department of Health (1991) Dietary Reference Values for
Food Energy and Nutrients for the United Kingdom.
Report on Health and Social Subjects, no. 41. London:
HMSO.
Department of Health (1994) Weaning and the Weaning
Diet. Report on Health and Social Subjects, no. 45.
London: HMSO.
European Community (1995) Nutrient and Energy Intakes.
Luxembourg: European Communities: The Stationary
Office.
Fomon SJ (1993) Nutrition of Normal Infants. St Louis:
Mosby.
Morgan JB, Redfern AM and Stordy BJ (1995) Healthy
eating for infants – mothers’ attitudes. Acta Paediatrica
84: 512–515.
National Research Council (1989) Recommended Dietary
Allowances, 10th edn. Washington, DC: National
Academy Press.
Paul AA, Whitehead RG and Black AE (1990) Energy
intakes and growth from two months to 3 years in
initially breast-fed children. Journal of Human Nutri-
tion and Dietetics 3: 79–92.
World Health Organization (1985) Energy and Protein
Requirements. WHO Technical Report Series no. 522
and FAO Nutrition Meetings Report Series no. 724.
Geneva: WHO.
INFANTS/Nutritional Requirements 3287
Breast- and Bottle-feeding
S Flack and V Shaw, Great Ormond Street Hospital for
Sick Children, London, UK
Copyright 2003, Elsevier Science Ltd. All Rights Reserved.
Introduction
0001 Breast milk is recognized as the best source of nutri-
tion for healthy infants. It is species specific. Opti-
mum infant nutrition from breast milk is dependent
on adequate volume and mother’s good health and
nutritional status. The practice of demand feeding
helps ensure adequate milk supply is maintained. In-
sufficient supply may be corrected by encouraging
more frequent feeds or expressing milk. The infant’s
suckling and milk removal stimulate increased breast
milk production.
0002 Breast milk composition is not standard. It is influ-
enced by maternal diet and by the mother’s nutri-
tional status. It changes during the course of
lactation to meet the requirements of the developing
infant. Milk shows diurnal variation; it varies from
mother to mother, day to day, and even during a
feed. At the initiation of a feed the milk has a low
fat content (fore milk) and this increases up to
fourfold during the feed (hind milk), to facilitate
satiety.
0003 The major change in breast milk composition
occurs as the colostrum, the initial milk produced,
changes to mature milk. Milk can be considered
mature at about day 10 postpartum (Table 1).
0004 The use of term pooled human milk as a sole source
of nutrition for preterm infants remains controver-
sial. It is recognized that early preterm mother’s
milk is more nutrient dense than term milk and is
therefore more suitable for the premature infant’s
requirements. However, additional energy and nutri-
ent fortification may be necessary.
Colostrum
0005 This is the milk produced in the first few days after
birth. It is compositionally distinctive from mature
human milk (Table 1). It contains a higher concen-
tration of protein, vitamin A, vitamin B
12
, sodium,
and some trace minerals. Initial colostrum has a high
sodium content (60 mmol l
1
), which decreases rap-
idly as the paracellular pathways close. Much of the
protein is present as secretory immunoglobulin A
(sIgA) which functions to protect the gut from infec-
tion. It has a lower fat content than mature breast
milk and, therefore, a lower energy content – 236 kJ
(56 kcal) per 100 g.
Mature Human Milk
Energy
0006The energy value of mature human milk is quoted as
289 kJ (69 kcal) per 100 g in standard food tables in
the UK. It is accepted that this is an average value, as
milk composition is variable. Advances in technology
have led to new estimates of its energy content.
Doubly labeled water analysis has shown the metab-
olizable energy content of breast milk to be 2219 kJ
(530 kcal) per liter at 6 weeks and 2428 kJ (580 kcal)
per liter at 3 months. The clinical significance of this
finding is unknown. Infant formulas are manufac-
tured to provide a similar energy content to that of
breast milk and contain approximately 2805 kJ
(670 kcal) per liter; this has lead to speculation that
infants receiving formula may be being overfed.
Protein
0007Protein in human milk is not homogeneous. It is
traditionally subdivided into two main groups: casein
and whey. Varying figures exist in the literature for
total whey and casein content at different stages of
lactation. The concentration of whey protein de-
creases during lactation. Some work suggests that the
casein to whey ratio is 10:90 in colostrum, changing
to a ratio of 45:55 in mature milk. Other literature
suggests that whey proteins continue to represent
about two-thirds of the protein in mature breast
tbl0001Table 1 Comparison of the composition of colostrum and
mature human milk
Nutrient per 100 g Colostrum Mature human milk
Energy (kJ) 236 289
Protein (g) 2.0 1.3
Fat (g) 2.6 4.1
Carbohydrate (g) 6.6 7.2
Sodium (mg) 47 15
Potassium (mg) 70 58
Calcium (mg) 28 34
Iron (mg) 0.07 0.07
Retinol (mg) 155 58
Carotene (mg) (135)
a
(24)
a
Vitamin D (mg) N
b
0.04
Thiamin (mg) Trace 0.02
Vitamin B
12
(mg) 0.1 Trace
Folate (mg) 2 5
Vitamin C (mg) 7 4
a
Estimated amount.
b
Significant quantities, but no reliable information.
From Macdonald S and Shaw V (1993) Breast- and bottle-feeding. In:
Macrae R, Robinson RK and Sadler MJ (eds) Encyclopaedia of Food
Science, Food Technology and Nutrition, pp. 2507–2511. London: Academic
Press, with permission.
Data from Holland B, Welch AA, Unwin ID et al. (1991) McCance and
Widdowson’s The Composition of Foods, 5th edn. Cambridge: Royal Society
of Chemistry/Ministry of Agriculture, Fisheries and Food.
3288 INFANTS/Breast- and Bottle-feeding
milk. The whey fraction’s major components are
a-lactalbumin, lactoferrin, and sIgA. The concentra-
tion of sIgA is approximately 9 g l
1
in colostrum,
falling to 1–2gl
1
in mature milk, representing
about 10% of the protein. sIgA acts against enteric
and respiratory immunogens. Lactoferrin also has an
antibacterial affect. Its binding of free iron inhibits
bacterial growth, enhances iron absorption, and
stimulates proliferation of the mucosa. Casein and
a-lactalbumin supply the essential amino acids.
0008 Breast milk also contains nonprotein nitrogen, e.g.,
urea, nucleotides, and free amino acids such as taur-
ine. Some of these constituents are believed to be
important in the development of the infant. Taurine
is the end product of methionine and cystine metab-
olism, but is considered a conditionally essential
amino acid in infants. It is required for retinal devel-
opment and digestion. It may also be protective
against oxidative cellular injuries.
Fat
0009 Fat is the main energy source in human milk, contrib-
uting 54% of the total energy in mature milk. The
amount of fat and fatty acid composition in breast
milk is variable and affected by maternal diet, nutri-
tional status, and starvation (by the catabolism of her
adipose tissue). It provides the essential fatty acids,
i.e., linoleic (C
18
:2n-6) and a-linolenic (C
18
:3n-3)
acids, contains long-chain polyunsaturated fatty
acids (LCPs), and is a carrier for the fat-soluble vita-
mins (A, D, E, and K) and prostaglandins. The two
principal functions of LCPs are as structural com-
ponents of membranes and as the precursors of the
biologically active eicosanoids.
0010 Fatty acid composition also changes during the
course of lactation. These changes can be linked to
the requirements for neonatal brain development.
Initial rapid cell division requirements are different
from that of myelination.
0011 Breast milk contains a form of inactive lipase,
which is activated by bile salts in the duodenum and
aids fat absorption in the infant. This is important, as
pancreatic lipase secretion and bile salt conjugation
are inefficient in the newborn.
Carbohydrate
0012 Lactose, a disaccharide composed of glucose and gal-
actose, is the main carbohydrate in human milk. It
constitutes approximately 80% of the total carbohy-
drate. Oligosaccharides are also present in both
colostrum and mature milk. The concentration of
oligosaccharides in breast milk decreases as colos-
trum changes to mature milk. Oligosaccharides and
lactose promote the growth of bifidus flora in the
gut. Unabsorbed lactose is converted by intestinal
microflora to lactic acid, creating an acidic pH
which inhibits the growth of many pathogens and
helps to protect the breast-fed infant from gastro-
intestinal infections. The additional benefit of this
low pH is its effect on calcium. It increases the solu-
bility of calcium and hence its absorption.
Vitamins and Minerals
0013Vitamin requirements can usually be met by adequate
volume of breast milk from a well-nourished mother.
Maternal diet influences the concentrations of most
vitamins in human milk. Cases of clinical deficiencies
of vitamins B
12
, D, and K have been observed. Clinical
rickets is rare but may occur in breast-fed infants,
usually related to the infant or mother having limited
exposure to sunlight. In the UK vitamin D supplements
are recommended if there is concern about maternal
diet or the infant’s exposure to sunlight. Vitamin B
12
is
only found in animal products, therefore there have
been case reports of deficiency (megaloblastic anemia)
in breast-fed infants of vegan mothers. Breast milk has
a low vitamin K content. Hemorrhagic disease occurs
in approximately 2% of breast-fed infants. Additional
vitamin K supplements are required during the period
of exclusive breast-feeding. In the UK it is usually given
intramuscularly at birth.
0014Breast milk provides all the major minerals and
trace elements known to be essential for healthy
infants in sufficient quantities for at least the first
4 months. The levels of calcium, phosphorus, and
iron are low, but their bioavailability from human
milk is excellent. However by 6 months additional
iron and zinc supplements may be necessary; these
requirements will be met by a balanced weaning diet.
Water
0015Mature human milk is 87% water. The fluid intake of
an exclusively breast-fed infant will always be ad-
equate provided demand feeding is practised. Add-
itional water supplements are unnecessary even in
very hot climates.
Nutritional Value of Cows’ Milk and Infant
Formula
0016Unmodified cows’ milk is not a suitable feed for
infants. It has a high renal solute load, inadequate
vitamin and mineral profile, and is poorly absorbed.
Infant formula is manufactured from modified cows’
milk as a substitute for human breast milk. Available
formulas in the UK conform to European Community
compositional guidelines. These formulas may be nu-
tritionally adequate but they lack the human anti-
infective, humoral, and cellular factors found in
breast milk.
INFANTS/Breast- and Bottle-feeding 3289