New findings on the ideal diet for infants under the age of 2 years
have buried several concepts and recommendations used by pediatricians
for a long time. In the last 10-15 years, there has been scientific
evidence confirming the importance of exclusive breast-feeding on
demand during the first 6 months of life, adequate and well-timed
complementary feeding, and maintenance of breast-feeding for two
or more years.
This article reviews complementary feeding of breast-fed infants
aged 6 to 24 months, a critical period for the promotion of adequate
nutrition. This is the stage at which there is a higher prevalence
of malnutrition and deficiency of certain micronutrients (
After the second year of life, it is difficult to reverse growth
retardation resulting from an early age ( ).
Complementary foods are defined as any solid or liquid foods with
nutritional value other than breastmilk, offered to breast-fed infants.
The foods especially prepared for infants before they start to eat
family food are called transition foods. These foods correspond
to the formerly called "weaning foods". This term has
not been used in order to avoid confusion as to its objective, which
is to complement breastmilk and not to replace it, thus initiating
When to start
The World Health Organization recommends that complementary feeding
be initiated after 4-6 months of life ( ).
The current tendency is to recommend complementary feeding around
6 months. Several countries, including Brazil, have already officially
adopted this recommendation, based on the evidence that complementary
feeding before 6 months of life (except in some special cases) does
not bring any advantage and could even be harmful to infant health.
The main argument against early complementary feeding initiation
is the increase in morbi-mortality, especially in regions where
sanitation conditions are poor. Early intake of complementary foods
reduces the intake of breastmilk ( )
and, as a consequence, infants receive fewer protection factors.
In addition, complementary foods can be a dangerous source of contamination
for infants. In Pelotas, state of Rio Grande do Sul, hospitalization
rates due to pneumonia were significantly higher in infants who
received complementary foods before 6 months of life, for either
breast-fed or artificially-fed infants ( ).
In another study carried out in Porto Alegre and Pelotas ( ),
the supplementation of breastmilk with any other food was associated
with na increase of diarrhea-related death rates. The prevalence
of diarrhea ( ),
disentery and fever ( )
was positively associated with complementary feeding in infants
aged between 4 and 6 months of life in Ghana and in India.
There is no agreement on the relationship between exclusive breast-feeding
and growth within the period of 4-6 months. Some studies showed
that the use of complementary feeding after 4 months in breast-fed
infants did not improve their growth, even when the complementary
foods offered were of good quality (
, - ).
On the other hand, Brazilian studies suggest that infants who receive
complementary feeding may have more rapid growth at this age than
exclusively breast-fed infants ( , ).
Complementary feeding before 6 months of life makes infants ingest
less breastmilk, that is, breastmilk is replaced with complementary
even when breast-feeding frequency is maintained ( ).
Many times, complementary foods given to infants during the first
months of life are less adequate than breastmilk in terms of nutrition.
Thus, early complementary feeding initiation is a drawback on infant
nutrition, in addition to reducing breast-feeding duration ( ),
interfering with the absorption of important nutrients found in
breastmilk such as iron and zinc ( - )
and reducing the efficacy of breast-feeding in the prevention of
new pregnancies ( ).
It is interesting to observe that the replacement of breastmilk
with complementary foods is less important after 6 months ( , ).
In many countries, the nutritional recommendations for infants
include delaying supplementation with certain foods as these are
highly alergenic (
Among these foods, we find cow's milk (responsible for 20% of food
allergies), which should be introduced at 9-12 months. Whole milk
should be used instead of non-skimmed milk. The United States recommends
avoiding certain kinds of food such as eggs, peanuts, nuts and fish
during the first year of life when there is a family history of
food allergy. The use of honey in the diet is usually recommended
after the first year of life, thus preventing the risk for botulism
In short, although there is no controversy on the ideal duration
of exclusive breast-feeding, current evidence advise that exclusive
breast-feeding be maintained up to 6 months. The American Academy
of Pediatrics has recently endorsed this recommendation (
In individual cases, complementary feeding initiation before 6
months may be recommended, especially when infants do not present
satisfactory growth with exclusive breast-feeding and/or present
evident hunger signs despite frequent breast-feeds. However, it
is necessary to take into consideration that current growth curves
are predominantly based on artificially-fed infants and, as appropriately
shown, the growth of healthy breast-fed infants aged between 3 and
9 months is usually inferior to that of weaned infants (
Therefore, the acritical use of current growth patterns may lead
to unnecessary food supplementation in healthy infants.
What kind of complementary foods
should be offered
Infants have to be fed adequate complementary foods at the right
time so that they can grow up in health. An adequate diet has to
be rich in energy, proteins and micronutrients (especially iron,
zinc, calcium, vitamin A, vitamin C and folates), free from contamination
(without pathogenic germs, toxins or harmful chemicals), not too
salty or spicy, easily eatable (adequate for the age), in adequate
amount, easily available and accessible. It is of paramount importance
that infants be fond of the diet and that this diet be culturally
acceptable ( ).
Some characteristics of an adequate diet for infants under 2 years
are described next.
The energy density of a food means the amount of calories per unit
of volume or weight of the food.
At the age of 6 months and there on, infants' energy density has
to be provided through complementary foods. Figure 1 shows that
the amount of energy that needs to be obtained from complementary
foods increases with age.
The amount of energy found in complementary foods necessary to fulfill
infant nutritional requirements varies according to the volume and
energy density of the breastmilk ingested by infants. In developing
countries, human milk energy content ranges from 0.53 to 0.70kcal/g,
whereas it is higher, between 0.60 and 0.83kcal/g1, in industrial
countries. Infants usually compensate for this variation in energy
concentration in breastmilk by varying their intake of breastmilk.
Anyway, infants in poorer countries usually require more energy
from complementary foods if compared to their peers in industrialized
countries. Table 1 presents estimates of the energy from complementary
foods required by infants in different age groups (up to 2 years),
taking into account place of residence and the volume of ingested
breastmilk ( ).
Figure 1 - Energy
requirements and required complementary food energy to supply the
nutritional needs of children younger than 2 years.
Table 1 -
Common complications in children with DKA, causes and treatment.
Infants have a self-regulating mechanism that controls their daily
energy intake. As a consequence, infants tend to eat smaller amounts
of high-calorie foods. In spite of this, infants on a high energy
density diet tend to have higher daily energy intake (
The limited gastric capacity of infants (30-40ml/kg of weight) may
prevent them from meeting their energy requirements if they have
a low energy density diet ( ).
On the other hand, if infants obtain a large amount of energy from
complementary foods, they can reduce the intake of breastmilk, which
is not advisable, especially for younger children.
The amount of energy obtained from fats in the diet of infants
under 2 years is arguable. Most authors state that fatty energy
probably covers between 30% and 45% of total energy intake in infants
under 2 years (
It is important to remember that 40% to 55% of the energy found
in human milk derive from fats.
As breastmilk fat content presents variation, the percentage of
energy obtained from fats in complementary foods may also vary.
This way, the percentage of energy obtained from fats in complementary
foods may be higher in the diets of infants whose mothers present
low fat milk, as in many populations from developing countries.
Assuming that the desired percentage of energy from fats (breastmilk
and complementary foods) is 30%, it is estimated that complementary
foods contain 14 to 21% of energy derived from fats in infants aged
between 6 and 11 months and 26% in infants between 12 and 23 months
when milk fat content is low (2.8g/100g). The diet for infants whose
mothers have adequate fat reserves (average milk fat concentration
around 3.8g/100g) should contain from 5 to 9% of energy obtained
from fats in infants aged between 6 and 11 months and 19% in infants
aged between12 and 23 months ( ).
In short, the amount of energy that infants should receive through
complementary foods depends on their age, amount of ingested breastmilk,
and frequency of complementary feeding. The recommended energy density
for infants with an average intake of breastmilk, who receive at
least three meals of complementary foods a day, ranges between 0.6kcal/g
in the 6-8 months of life to 1.0kcal/g in the 12-23 months. When
breastmilk intake is lower or infants have growth retardation, energy
density must be higher, ranging from 0.8 to 1.2kcal/g (
The necessary amount of fat obtained from complementary foods also
varies and depends on breastmilk fat content. Nevertheless, groups
of experts in several countries believe that fat intake during the
first two years of life may not have restrictions ( ).
A multicenter study on food consumption carried out in Brazil (
showed that, usually, the diet of Brazilian infants under 2 years
is adequate in terms of calories. However, energy density was low,
which could be associated with the kind of food ingested or also
the consistency of this food. Infants are commonly fed "soft",
In general, the amount of proteins in a diet is adequate if it
contains an adequate energy content, except in populations which
eat foods that are predominantly poor in proteins e.g.: yam and
Isolated protein deficiency, in opposition to former beliefs, does
not seem to determine height deficiencies in infants who belong
to a low socioeconomic level in developing countries ( , ).
The protein density (grams of proteins per 100kcal of food) recommended
for the complementary feeding of infants aged between 6 and 24 months
is 0.7g/100kcal (
The amount and digestibility of proteins should be taken into consideration
when assessing complementary feeding adequacy. Proteins of highest
biological values and best digestibility are found in human milk,
followed by proteins of animal origin (meat, milk, eggs). A proper
combination of vegetables can also provide high-quality proteins
as in mixing rice and beans (
According to the Multicenter Study on Food Consumption (
the diet of Brazilian infants under 2 years usually contains a concentration
of proteins above recommendations, increasing with age.
Although the amount of iron found in breastmilk is low, it is enough
to meet iron requirements during the first 6 months of life, in
full-term babies, thanks to iron stores. After 6 months, iron stores
are depleted, and it is necessary to provide iron through complementary
foods (Figure 2). Preterm babies presenting low weight at birth
have fewer body iron stores, and need supplementation with iron
before the 6th month of life.
Figure 2 - Iron
requirements and required iron necessarty to complementary food
energy to supply the nutritional needs of children younger than
Iron bioavailability, that is, how much of the ingested iron is
really absorbed by the body and available for use, is extremely
important. The iron that is best absorbed and used by human species
is that found in breastmilk, with a rate of up to 70% when breast-feeding
is exclusive (
The iron found in foods of animal origin is better absorbed (up
to 22%) than the iron of vegetable origin (1 to 6%). The latter
is better absorbed in the presence of meat, fish, fructose and ascorbic
acid, and less absorbed when eaten with egg yolk, milk, tea, maté
tea or coffee ( ).
Among the products of animal origin, meat (especially red meat)
and some organs (especially liver) contains higher iron density
and better bioavailability than milk and its by-products. Egg yolk
is rich in iron, but its absorption is poor. Some products of vegetable
origin contain reasonable amounts of iron, but present low bioavailability.
Among these products we find beans, lentils, soy beans, and leafy
vegetables (Swiss chard, kale, broccoli, mustard, chicory).
A diet with high iron bioavailability (over 19% of absorption)
is usually a diversified diet with reasonable amounts of meat, fish
and poultry (over 90g) and foods that are rich in ascorbic acid
The recommended iron density (mg/100kcal) in complementary foods
is 4mg/100kcal for infants between 6 and 8 months of life, 2.4mg/100kcal
between 9-11 months and 0.8mg/100kcal for infants between 12 and
24 months. The Multicenter Study on Food Consumption ( )
revealed that the average iron density in the diet of Brazilian
infants under 2 years is way below recommendations: from 0.49 to
0.69 for infants between 6 and 12 months and from 0.53 to 0.69 for
infants in the second year of life. These findings are coherent
with high anemia rates presented among Brazilian infants ( - ).
Acknowledgedly, the iron density of complementary foods in developing
countries does not meet the iron requirements of infants under 2
The adequate amount of iron in complementary foods can only be achieved
through the consumption of iron-fortified foods or through animal
products in large amounts. Infants hardly eat iron-rich foods (liver,
meat, fish). Therefore, it is necessary to use some strategies to
increase iron intake among infants between 6 and 24 months such
as food fortification, and supplementation with iron. The intake
of vitamin-C-rich foods (orange, guava, lemon, mango, papaya, melon,
banana, passion fruit, peach, tomato, green pepper, green leaves,
cabbage, broccoli, cauliflower) at meals increases the amount of
iron that is absorbed. Do not forget that cooking destroys part
of vitamin C.
The role of zinc in the prevention of morbi-mortality caused by
infectious diseases had not been recognized until recently.
In developing countries, the average zinc density (mg/100kcal) in
foods eaten by infants under 1 year of life is lower than the recommendation
(0.8mg/100kcal for infants between 6 and 8 months and 0.5 mg/100kcal
for infants between 9 and 11 months) ( ).
Similarly to what occurs with iron, infants between 6 and 8 months
have difficulty meeting their body zinc requirements through complementary
feeding ( , ).
Infants over 8 months can meet their body zinc requirements by ingesting
relatively high amounts of liver and dry fish.
Zinc density and bioavailability is higher in products of animal
origin, especially meat and organs (mainly liver) and egg yolk.
Vegetable products are usually poor in zinc and have low bioavailability,
especially in grains and legumes with high concentration of phytates.
Differently from iron, ascorbic acid does not increase zinc bioavailability.
Vitamin A content
In several developing countries, infants ingest adequate amounts
of vitamin A (
Infants who are fed breastmilk with adequate concentrations of vitamin
A meet their daily vitamin A requirement in a relatively easy way
through adequate complementary foods. However, in vitamin A deficiency
endemic areas, complementary feeding is na important source of vitamin,
since vitamin A concentration in breastmilk may be low in these
regions. In addition, vitamin A absorption may be hindered when
infants have a low-fat diet; this often occurs in poverty-stricken
populations. Carotene and retinol absorption may probably be improved
if complementary foods are fed together with breastmilk (some time
before or after that) ( ).
In endemic areas, where the concentration of vitamin A in breastmilk
may be low, infants need a higher amount of vitamin A to meet their
needs. This can be achieved through supplementation of mothers with
vitamin A and/or with increased intake of foods that are rich in
vitamin A such as liver, egg yolk, dairy products, leafy vegetables,
vegetables and orange-colored fruits (carrots, pumpkin, red or yellow
pepper, mango, passion-fruit, papaya) (
Basically, there are no studies in Brazil on vitamin A ingestion
by infants under 2 years. It is known that in endemic areas (Northeast
and some communities outside this region) ingestion may be low since
the prevalence of vitamin A deficiency is high (
The Multicenter Study on Food Consumption ( )
showed that, in general, the average intake of vitamin A was adequate
in infants under 2 years. However, when families were categorized
according to their income, the diet of infants whose families had
a monthly income less than or the same as 2 minimum wages revealed
to be deficiency in vitamin A.
Amount and frequency
At the beginning, the amount of complementary foods must be low
and then gradually increased. New foods also need to be gradually
introduced, one at a time, with an interval of 3 to 7 days so that
possible adverse reactions of each food can be observed separately.
It is important to say that breast-feeding frequency does not have
to be changed because of complementary feeding.
In the 9th month, infants can already be fed a diversified diet.
Frequent and bulky meals should be avoided in breast-fed infants
since the more foods they eat, the less breastmilk they will ingest.
Do not forget that infants' gastric capacity is low and that infants
adapt the intake of foods according to energy density ( , ).
Complementary feeding frequency in infants varies according to
the energy density of foods in the diet, amount of breastmilk ingested,
and size of infants. Medium-sized infants aged between 6 and 8 months
with average intake of breastmilk need 2 meals a day if energy density
of foods is higher than or equals 0.9kcal/g, or 3 meals if energy
density is less than 0.6 to 0.9 kcal/g. Between 9 and 11 months
of life, 3 daily meals are necessary if energy density is higher
than or equals 0.8kcal/g or 4 meals if energy density is 0.6 to
0.8kcal/g. In the second year of life, e meals are enough if the
diet includes high energy density (at least 1.0kcal/g). In the case
of low-calorie diets, 4 or 5 daily meals are necessary (
Many times, it is difficult to assess the amount of breastmilk
ingested by infants; therefore, the World Health Organization recommends
that complementary foods with adequate energy density be initially
offered 3 times a day. The amount and frequency of feeding should
be gradually increased so that 12-year-old infants receive complementary
foods 5 times a day (3 meals and 2 snacks). Infants who are not
breast-fed or are breast-fed on an infrequent basis need to be fed
complementary foods 5 times a day from the time complementary feeding
is initiated (
At the beginning, foods should be soft (mashed), without being
diluted (it is not advisable to blend foods in a mixer). Soups and
watery/soft foods do not provide the calories infants need. At this
stage, the so-called transition foods should be especially prepared
for infants. After 8 months of life, infants can be fed the same
foods the family eats provided that they are mashed, shredded, chopped
or cut into small pieces.
The best period for introducing complementary foods, whether before,
during or after breast-feeds, is not well-established. There is
at least one study showing that total suction time and daily energy
intake do not vary according to the order in which complementary
foods are offered ( ).
In an attempt to prevent a substantial reduction in the amount of
breastmilk intake, many authors recommend offering complementary
foods after breast-feeds. Others advocate that complementary foods
should be given before breast-feeds in order to facilitate recognition
of new tastes and textures ( ).
There is little information about the number of daily meals fed
to infants under 2 years in Brazil. The Multicenter Study on Food
revealed that over 90% of infants in this age group are fed at least
4 times a day. Most infants have 5 to 6 meals a day after the sixth
month of life.
Hygiene of complementary foods
Hygiene of complementary foods, which includes preparation, later
storage and administration, is important for the promotion of infant
It is believed that more than half of diarrhea bouts in infants
under the age of 5 is associated to infant nutrition ( );
and complementary foods play a vital role in the transmission of
diarrheal diseases ( ).
Contamination of complementary foods is very common in developing
countries due to contaminated water, poor personal hygiene (contaminated
hands of whom is preparing the food) and inadequate cleaning of
eating utensils (especially baby bottles and their nipples) and
inadequate storage of foods after preparation. Food contamination
is common when it is stored at room temperature as the proliferation
of pathogenic bacteria is favored (
Frequently, in poverty-stricken populations, foods that are stored
under unfavorable conditions are given to infants without being
heated or are inadequately reheated, resulting in the intake of
a great number of pathogenic germs ( ).
The following hygiene practices should be adopted when handling
foods: washing hands with soap before their preparation; using always
fresh food; washing raw foods properly; using clean utensils; avoiding
the use of bottles and their respective nipples; storing perishable
or freshly prepared foods in the refrigerator whenever possible;
cooking foods properly; eating foods within 2 hours after preparation
if not stored in a refrigerator; properly reheating prepared foods
or foods stored at room temperature for over 2 hours; and protecting
foods and utensils against animals (rats, cockroaches, flies) and
Interestingly, in Uganda, the use of cups was more efficient in
reducing bacterial counts than the cleaning of eating utensils,
since bottles and nipples which were washed in cold or hot water
were more contaminated than cups that were submitted to the same
Factors that facilitate/interfere with adequate complementary
Some factors should be considered so that infants can have an adequate
diet. These factors include appetite/anorexia, variety/monotony
Lack of appetite could lead to a significant reduction in energy
intake and, consequently, growth deficiencies. The incidence of
anorexia during the first year of life increases with age - from
2.2% in the first month to 31.7% in the 12th month ( ).
The factors that cause anorexia or low intake of complementary foods
include repeated diets ( );
micronutrient deficiencies, especially iron and zinc; and emotional
problems ( ).
When breast-fed infants are anorexic, the intake of energy from
complementary foods is markedly reduced if compared to the energy
intake from breastmilk itself (
Even infants who are healthy and have good appetite should be assisted
and encouraged to eat at mealtime. This requires patience since
infants eat slowly, spread food about the place, and get easily
distracted. Adults should encourage infants to eat by themselves,
always making sure that they are ingesting enough food. Infants
who are sleepy or have waited too long for being fed may lose their
appetite and not feed properly. Adults cannot force or blackmail
infants into eating.
If infants are anorexic due to a disease, a more flexible attitude
towards eating hours and habits can help them to feed more properly.
During these periods, they should be fed more frequently (preferably
breast-fed); they should be offered their favorite foods; and foods
that have high energy density and a consistency that facilitates
swallowing and does not irritate the mucosas (acid foods) if they
feel pain when swallowing and/or chewing. In the event of diseases
that cause vitamin A depletion such as measles, diarrhea and acute
respiratory infections (
infants should be fed foods that are rich in this vitamin.
After an infection, during rehabilitation, infants have an appetite
that is above normal levels, as an attempt to compensate for weight
loss. In this period, foods that are rich in energy and that contain
a protein/energy ratio above normal should be offered more frequently.
Additional protein should contain, preferably, high biological value
(meat, dairy products and eggs), also offering more iron, zinc and
vitamin A (
Only a diversified diet can provide infants with adequate nutrition.
The diet of Brazilian infants is usually repetitive. The Multicenter
Study on Food Consumption (
showed that 70% of calories ingested by infants between 6 and 12
months are supplied by 5 to 8 products. In the second year of life,
the diet is a bit more diversified, including 8 to 11 products,
which provide 70% of the energy ingested. According to this same
study, the intake of fruits, vegetables and legumes is low among
infants under 2 years.
Infants should be early exposed to different kinds of food on a
regular basis so that they easily accept them and do not reject
new foods (
Therefore, if they are exposed to these foods on a regular basis,
they end up accepting them, and then these foods may be incorporated
into their regular diet ( , ).
Initial rejection of food is often interpreted as permanent aversion,
and as a consequence, that kind of food is excluded from the diet.
It was reported that breast-fed infants accept new foods more easily
than non-breast-fed ones, which could be associated with exposure
to different tastes infants experience through breastmilk intake
The way in which foods are initially presented to infants is also
important for their future eating habits as they start to enjoy
the food that way (
Therefore, it is advisable to offer infants foods with low sugar
and salt contents at the beginning.
Infants have the tendency to prefer high energy density foods (
However, an exaggerated intake of calorie-rich foods may restrict
the ingestion of a diversified diet, since infants get satiated
quickly and start to reject other foods.
Intrauterine experiences are likely to contribute to infants' preferences
for taste later on. An offspring of mice submitted to diets with
different concentrations of sodium showed higher or lower preference
for this mineral, according to the intake of sodium during pregnancy
( , ).
In addition, amniotic fluid is aromatic and its smell is influenced
by mothers' diet ( ).
The similarity of aromas between amniotic fluid and breastmilk may
be involved in the preference of new-borns for the smell of breastmilk
Experiments with mammals suggest that taste preferences may be
influenced by mothers' diet (
Chemical compounds that provide foods with taste and smell are ingested
by infants through breastmilk; this way, infants are gradually introduced
to their family eating habits ( ).
Breast-feeding, in addition to all its advantages, is "an important
source of information and way of learning about the different tastes
asociated with mothers, families and cultures" ( ).
Composition of breastmilk changes as lactation progresses. Lactose
levels reduce and increase levels of chloride, making breastmilk
have a slightly salty taste ( ).
Such a change may help infant to accept complementary foods at the
How to offer complementary foods
Complementary foods should be offered with a spoon and cup. Today,
the use of bottles is not recommended since it is a source of infection,
reduces breast sucking time, interfering with breast-feeding on
demand, and may alter the dynamics of oral feeding (
Bottle-feeding, when initiated before the onset of lactation, may
be confusing to infants as breast sucking and bottle sucking techniques
are distinct ( ).
Sucking milk out of the breast requires muscle movements to lower,
protract, elevate and retract the jaw, besides tongue movements
used to extract the milk. In bottle-feeding, there is no need for
protracting and extruding jaw movements or tongue movements ( ).
There is evidence that some new-borns, after exposure to bottle-feeding,
have difficulty in breast-feeding ( , ).
Several studies report the association between bottle-feeding and
early weaning ( ).
Differently from expectations, infants accept well being fed with
a spoon and cup.
A lot has been learned about adequate infant feeding throughout
the last years. Consequently, many concepts and practices that had
been preconized for a long time are now outdated, for instance,
rigid breast-feeding schedules, use of water and teas during the
first months of life, early introduction (before 6 months) of juices
and other foods, and undue importance to breast-feeding in the second
year of life. The present article, based upon scientific evidence,
presents an updated review on complementary feeding of infants under
two years. Health professionals have the duty of incorporating and
advertising these new findings, with the aim of providing infants
with adequate nutrition. The Brazilian Ministry of Health in association
with the Panamerican Health Organization hired a group of experts
to design the "Dietary Guide for Brazilian Infants under 2
years". This document, which is being printed, contains technical
and scientific bases, dietary and nutritional diagnostics of Brazilian
infants under the age of 2, and recommendations through "Ten
steps to a healthy diet in infants under 2 years". This document
and also the present review have important information that could
serve as guidelines for organizing the information that is going
to be conveyed to the target population.
The text below was written by Gabriela Mistral, and is food for
thought on the urgent need for actions that can improve infant health
"We are at fault for many mistakes and errors,
but our most appalling crime is the abandonment of children,
neglecting the source of life.
Many of our needs can wait.
Now that their bones are under formation,
Their blood is being formed
Their senses are developing.
To them we cannot say "tomorrow"
"Today" is what we must say