Nutritional Requirements of Infants and Children1



Nutritional Requirements of Infants and Children1


William C. Heird





The nutritional requirements of infants and children reflect this population’s unique maintenance needs as well as the needs for growth and developmental changes in organ function and body composition. Moreover, because the metabolic rate of infants and children is greater and the turnover of nutrients more rapid than those of the adult, the unique nutrient needs for growth and development are superimposed on higher maintenance requirements than those of the adult. In addition, the potential impact of intake during early life on later development and health must be considered. Finally, provision of these greater needs, particularly to the smaller members of this population, is hindered by their lack of teeth as well as their limited digestive and metabolic processes.

In this chapter, the nutrient needs of normal infants and children, as well as factors of importance in meeting these needs, are discussed, as are the nutritional needs of low birth weight (LBW) infants and ways of providing these needs. The nutrient needs of infants and children with acute or chronic diseases affecting nutrient needs or management are discussed in another chapter, which also includes a general discussion of approaches to providing the nutritional needs of compromised infants and children and a detailed discussion of parenteral nutrition in infants and children.


NUTRIENT NEEDS OF THE NORMAL INFANT AND CHILD

The estimated average requirement (EAR) of a specific nutrient is the amount of that nutrient that results in some predetermined physiologic end point. In infants, the major end point is maintenance of satisfactory rates of growth and development and prevention of specific nutrient deficiencies. The EAR is usually defined experimentally, often over a relatively short period and in a relatively small study population. By definition, the EAR meets the needs of roughly half of the population in which it was established, but not necessarily the needs of the other half. For some, it may be excessive, whereas for others it may be inadequate.

The recommended intake or recommended dietary allowance (RDA) of a nutrient, conversely, is the intake deemed by a scientifically knowledgeable group to meet the “requirement” of most healthy members of a population.
In general, if the EAR of a specific population is known and is normally distributed, the RDA is set at the EAR plus two standard deviations. RDAs are useful for assessing the nutrient intakes of individuals; that is, the usual intake of a nutrient at or higher than its RDA has a low probability of being inadequate. RDAs are less useful for assessing the adequacy of the nutrient intake of a group.

In recognition of the lack of a valid EAR for many nutrients and the uncertainty of an RDA based on limited information, the latest recommendations of the Food and Nutrition Board of the Institute of Medicine (1, 2, 3, 4, 5, 6), are designated dietary reference intakes (DRIs). These include RDAs for those nutrients for which an EAR has been established; therefore, an RDA can be established reliably, as well as other “reference intakes,” including adequate intake (AI) and tolerable upper intake level (UL).

The AI of a specific nutrient is the daily intake of that nutrient by a group of healthy individuals. It is based on the group’s observed or approximated intake of that nutrient. Thus, a mean intake of a nutrient at or high than the AI has a low probability of being inadequate. The content of specific nutrients in the average volume of milk consumed by healthy, normally growing, breast-fed infants is considered an AI of most nutrients for infants less than 6 months of age. This definition is consistent with national and international recommendations for exclusive breast-feeding for the first 6 months of life (7, 8). For the 7- to 12-month-old infant, the AI of many nutrients is set at the amount of the nutrient in the average volume of human milk plus the average amount of complementary foods consumed by healthy, normally growing 7- to 12-month-old infants. The AIs of other nutrients for the 7- to 12-month-old infant are extrapolated from that of the 0- to 6-month-old infant or that of the older child or adult. An EAR for a few nutrients has been established for the 7- to 12-month old child as well as older infants and children, either directly or by extrapolation from EARs of adults or older children. For these, an RDA can be (and has been) established.

The UL is the highest daily intake of a specific nutrient that is likely to pose no risk. It is not a recommended level of intake but rather an aid for avoiding excessive intakes and adverse effects secondary to such intakes.

The most recent reference intakes of various nutrients proposed by the Food and Nutrition Board of the Institute of Medicine for infants and children less than 8 years of age are summarized in Table 54.1. ULs of those nutrients for which one has been established are summarized in Table 54.2. The DRIs of some nutrients for the 0- to 6-month old infant, the 7- to 12-month-old infant, the 1- to 3-year-old child, and the 4- to 8-year-old child are discussed briefly in the sections that follow.


Energy

Per unit of body weight, the normal infant and young child require at least twice as much energy as the adult (i.e., 80 to 100 kcal/kg/day versus 30 to 40 kcal/kg/day). This greater need reflects primarily the infant’s higher resting metabolic rate and special needs for growth and development.

The estimated energy requirement (EER) of the infant and young child proposed by the Food and Nutrition Board of the Institute of Medicine (5), that is, the energy intake predicted to maintain energy balance (which is not the same as EAR), is based on analysis of total energy expenditure data obtained by the doubly labeled water method (TEE = 88.6 × weight – 99.4) plus an allowance for energy deposition incident to growth as determined from measurements of weight gain and body composition of normally growing infants and young children (9).

Equations for predicting the EER (kcal/day) of infants and children less than 3 years of age are as follows:



  • 0 to 3 months (88.6 × weight of infant – 99.4) + 175


  • 4 to 6 months (88.6 × weight of infant – 99.4) + 56


  • 7 to 12 months (88.6 × weight of infant – 99.4) + 22


  • 1 to 3 years (88.6 × weight of child – 99.4) + 22

The EER of the infant younger than 6 months of age determined in this way is very close to the mean energy intake of exclusively breast-fed infants.

The EER of the 3- to 8-year-old child also is based on total expenditure measured by the doubly labeled water method plus an allowance for growth (20 kcal/day) and an adjustment for physical activity level. For this age group, the equation predicting TEE differed between boys and girls and included age, height, and weight. This was adjusted for physical activity level (PC, 1.0 for sedentary to 1.42 [boys] or 1.56 [girls] if very active). For 3- to 8-yearold boys, the equation for EER (kcal/day) is as follows:

EER = 88.5 – 61.9 × age [years] + PC × (26.7 × weight [kg] + 903 × height [m]) + 20

For girls it is the following:

EER = 135.3 – 30.8 × age [years] + PC × (10 × weight [kg] + 934 × height [m]) + 20

With respect to the source of energy, no evidence exists that either carbohydrate or fat is superior, provided total energy intake is adequate. Sufficient carbohydrate to avoid ketosis or hypoglycemia is required (˜5.0 g/kg/day), as is enough fat to avoid essential fatty acid deficiency (0.5 to 1.0 g/kg/day of linoleic acid plus a smaller amount of α-linolenic acid).

The AIs of carbohydrate and fat proposed by the Food and Nutrition Board of the Institute of Medicine (5) for the 0- to 6-month-old (i.e., 60 g/day [˜10 g/kg/day] and 31 g/day [˜5 g/kg/day], respectively) are based on the carbohydrate and fat contents of an average intake of human milk. The AIs for the 7- to 12-month-old infant (i.e., 95 g/day [˜10.5 g/kg/day] and 30 g/day [˜3.3 g/kg/day], respectively) are based on the average consumption of carbohydrate and fat from human milk plus complementary foods. An EAR for carbohydrate for the older child was
established by extrapolation from adult requirements. It is 100 g/day for both the 1- to 3-year-old (8.3 g/kg/day) and the 4- to 8-year-old (5 g/kg/day) child. The RDA is 130 g/ day (10.8 and 6.5 g/kg/day, respectively, for the younger and older child). AIs for fat beyond 1 year of age have not been determined.








TABLE 54.1 DIETARY REFERENCE INTAKES OF NUTRIENTS FOR NORMAL INFANTSa
























































































































































































































































































REFERENCE INTAKE PER DAY


NUTRIENT


0-6 mo (6 kg)


7-12 mo (9 kg)


1-3 y (13 kg)


4-8 y (22 kg)


Energy (kcal [kJ]/24 h)


550 (2,310)


750 (3,013)


1,074 (4,494)


See text


Fat (g/24 h)


31


30





Linoleic acid (g/24 h)


4.4


4.6


7


10



α-Linolenic acid (g/24 h)


0.5


0.5


0.7


0.9


Carbohydrate (g/24 h)


60


95


130


130


Protein (g/24 h)


9.3


11a


13.7a


21a


Electrolytes and minerals







Calcium (mg/24 h)


210


270


500


800



Phosphorus (mg/24 h)


100


275


460a


500a



Magnesium (mg/24 h)


30


75


80a


130a



Sodium (mmol/24 h)


5


6


42


53



Chloride (mmol/24 h)


5


16


42


53



Potassium (mmol/24 h)


10


18


77


97



Iron (mg/24 h)


0.27


11a


7a


10a



Zinc (mg/24 h)


2


3a


3a


5a



Copper (µg/24 h)


200


220


340a


440a



Iodine (µg/24 h)


110


130


90a


90a



Selenium (µg/24 h)


15


20


20a


30a



Manganese (mg/24 h)


0.003


0.6


1.2


1.5



Fluoride (mg/24 h)


0.01


0.5


0.7


1.0



Chromium (µg/24 h)


0.2


5.5


11


15



Molybdenum (µg/24 h)


2


3


17a


22a


Vitamins







Vitamin A (µg/24 h)


400


500


300a


400a



Vitamin D (µg/24 h)


5


5


5


5



Vitamin E (mg α-TE/24 h)


4


6


6a


7a



Vitamin K (µg/24 h)


2.0


2.5


30


55



Vitamin C (mg/24 h)


40


50


15a


25a



Thiamin (mg/24 h)


0.2


0.3


0.5a


0.6a



Riboflavin (mg/24 h)


0.3


0.4


0.5a


0.6a



Niacin (mg NE/24 h)


2


4


6a


8a



Vitamin B6 (µg/24 h)


0.1


0.3


0.5a


0.6a



Folate (µg)


65


80


150a


200a



Vitamin B12 (µg/24 h)


0.4


0.5


0.9a


1.2a



Biotin (µg/24 h)


5


6


8


12



Pantothenic acid (mg/24 h)


1.7


1.8


2


3



Choline (mg/24 h)


125


150


200


250


Water (L/24 h)


0.7


0.8


1.3


1.7


α-TE, α-tocopherol equivalent; NE, niacin equivalent.


aRecommended dietary allowance; other intakes are adequate intake.


Data from references 1, 2, 3, 4, 5 to 6, with permission.


The AIs of n-6 polyunsaturated fatty acids (PUFAs; primarily linoleic acid) and n-3 PUFAs (primarily α-linolenic acid) proposed for the 0- to 6-month-old, based on the average consumption of these fatty acids by exclusively breast-fed infants, are 4.4 g/day (˜0.73 g/kg/day) and 0.5 g/day (˜83 mg/kg/day), respectively (5). Those for the 7- to 12-month-old child, based on the average consumption of these fatty acids from human milk plus complementary foods, are 4.6 g/day (˜0.5 g/kg/day) and 0.5 g/day (˜56 mg/kg/day), respectively (5). AIs of these fatty acids for the 1- to 3-year-old and the 4- to 8-yearold child are based on the median intakes of these fatty acids by children of these age groups reported by the Continuing Survey of Food Intake by Individuals. They are 7 and 10 g/day (0.58 and 0.5 g/kg/day), respectively, for n-6 PUFAs and 0.7 and 0.9 g/day (58 mg/kg/day and 45 mg/kg/day), respectively, for n-3 PUFAs. On average, AIs of these two fatty acid groups account for 5% to 7% and 0.5% to 1.0% of the EER, respectively.

Concern exists that infants may also require a preformed intake of at least some of the longer-chain, more unsaturated derivatives of linoleic and α-linolenic acids (e.g., arachidonic and docosahexaenoic acids). These fatty acids are present in human milk but, until recently, were not present in formulas. Further, the contents of these fatty acids in plasma and erythrocyte lipids are lower in infants fed unsupplemented
formulas versus breast-fed infants (10, 11) or those fed formulas supplemented with these fatty acids. The brain content of docosahexaenoic but not arachidonic acid also is lower in infants fed unsupplemented formula than in breastfed infants (12, 13). However, the results of functional outcome studies of breast-fed versus formula-fed infants and infants fed formulas with and without arachidonic and docosahexaenoic acid are inconclusive (14, 15, 16). Overall, these studies provide little evidence that the absence of these fatty acids in term infant formulas is problematic provided intakes of both linoleic and α-linolenic acid are adequate (17). There also is no convincing evidence that the amounts of long-chain PUFAs (LC-PUFAs) in available supplemented formulas pose safety concerns, and a convincing argument can be made for the likelihood that some infants may benefit from the supplemented fatty acids.








TABLE 54.2 TOLERABLE UPPER INTAKE LEVELS OF NUTRIENTS FOR INFANTS AND YOUNG CHILDREN








































































































































































































































































INTAKE PER DAY


NUTRIENT


0-6 mo (6 kg)


7-12 mo (9 kg)


1-3 y (13 kg)


4-8 y (22 kg)


Energy (kcal [kJ]/24 h)


ND


ND


ND


ND


Fat (g)


ND


ND


ND


ND


Carbohydrate


ND


ND


ND


ND


Protein (g/24 h)


ND


ND


ND


ND


Electrolytes and minerals







Calcium (mg/24 h)


ND


ND


2,500


2,500



Phosphorus (g/24 h)


ND


ND


3


3



Magnesium (mg/24 h)


ND


ND


65


110



Sodium (mg/24 h)


ND


NA


65


83



Chloride (mg/24 h)


ND


ND





Potassium (mg/24 h)


ND


ND


ND


ND



Iron (mg/24 h)


40


40


40


40



Zinc (mg/24 h)


4


5


7


12



Copper (µg/24 h)


ND


ND


1,000


3,000



Iodine (µg/24 h)


ND


ND


200


300



Selenium (µg/24 h)


45


60


90


150



Manganese (mg/24 h)


ND


ND


2


3



Fluoride (mg/24 h)


0.7


0.9


1.3


2.2



Chromium (µg/24 h)


ND


ND


ND


ND



Molybdenum (µg/24 h)


ND


ND


300


600


Vitamins







Vitamin A (µg/24 h)


600


600


600


900



Vitamin D (µg/24 h)


25 (1,000 IU)


50 (2,000 IU)


50 (2,000 IU)




Vitamin E (mg α-TE/24 h)


ND


ND


200


300



Vitamin K (µg/24 h)


ND


ND


ND


ND



Vitamin C (mg/24 h)


ND


ND


400


650



Thiamin (mg/24 h)


ND


ND


ND


ND



Riboflavin (mg/24 h)


ND


ND


ND


ND



Niacin (mg/24 h)


ND


ND


10


15



Vitamin B6 (µg/24 h)


ND


ND


30


40



Folate (µg)


ND


ND


300


400



Vitamin B12 (µg/24 h)


ND


ND


ND


ND



Biotin (µg/24 h)


ND


ND


ND


ND



Pantothenic acid (mg/24 h)


ND


ND


ND


ND



Choline (mg/24 h)


ND


ND


1


1


Water (L/24 h)


ND


ND


ND


ND


α-TE, α-tocopherol equivalent; IU,international units; ND, data are insufficient to establish a tolerable upper intake level for normal individuals.


Data from references 1, 2, 3, 4, 5 to 6, with permission.


In toto, the specific needs for carbohydrate and fat, including LC-PUFA, amount to no more than 30 kcal (125.5 kJ)/kg/day, or only approximately one third of infant and young child’s EER. Whether the remainder should consist predominantly of carbohydrate, predominantly of fat, or equicaloric amounts of each is not known. Human milk and most currently available formulas contain roughly equicaloric amounts of each. Because a higher percentage of energy as carbohydrate increases osmolality and a higher percentage as fat may exceed the infant’s ability to digest and absorb fat, roughly equicaloric amounts of each seems reasonable.

In concert with the recommendation that the dietary fat intake of the general population be reduced to improve cardiovascular health, it has been suggested that this guideline be applied to infants and young children. However, because fat is a major source of energy as well as the only source of essential fatty acids, concern exists that such diets may limit growth. Thus, groups responsible for making recommendations for infants and young children have not endorsed this recommendation for
those less than 2 years of age (18). However, little reason exists not to reduce intake of cholesterol and saturated fat. The Acceptable Macronutrient Distribution Range of fat suggested for the 1- to 3-year-old child by the Panel on Macronutrients of the Food and Nutrition Board of the Institute of Medicine (5) is 30% to 40% of energy. The range suggested for the 4- to 8-year-old child is 25% to 35% of energy (5% to 10% of n-6 and 0.6% to 1.2% as n-3 fatty acids).

Until recently, few actual data concerning growth of infants and young children receiving “low-fat” diets were available, but a study in Finland suggests that the fear of growth failure with such diets may be overrated (19). In this study of more than 1000 infants, half of whom received dietary counseling to limit saturated fat and cholesterol intakes and half of whom did not, growth of the 2 groups did not differ. Although energy and fat intake of the intervention group was somewhat lower than that of the control group, the mean fat intake of both groups was close to 30% of total energy. The intervention group also had lower serum cholesterol concentrations at 3 years of age or on termination of the study.


Protein

The protein needs of the infant and young child, per unit of body weight, also are greater than those of the adult, reflecting primarily the infant’s and young child’s additional needs for growth. The AI of protein established by the Food and Nutrition Board of the Institute of Medicine (5) for the 0- to 6-month-old infant, 9.3 g/day or approximately 1.5 g/kg/day (assuming a mean weight of 6 kg), is based on the observed mean protein intake of infants fed principally with human milk.

EARs for protein intake were established for the 7- to 12-month old infant as well as the 1- to 3-year-old and 4- to 8-year-old child (5). These values are based on maintenance protein needs plus the additional need for protein deposition as determined by measurements of body composition of normally growing infants and children, assuming an efficiency of deposition of dietary protein intake of 56%. The EAR for the 7- to 12-month-old infant is 0.98 g/ kg/day. That for the 1- to 3-year-old child is 0.86 g/kg/day and for the 4- to 8-year-old child is 0.76 g/kg/day. Because the calculated coefficient of variation is approximately 12%, RDAs are 1.24 × EAR: 1.2 g/kg/day for the 7- to 12-month-old infant, 1.05 g/kg/day for the 1- to 3-yearold child, and 0.95 g/kg/day for the 4- to 8-year-old child.

The required intake of protein is a function of its quality, which usually is defined as how closely its indispensable amino acid pattern resembles that of human milk protein. It also follows that the overall quality of a specific protein can be improved by supplementing it with the lacking (or limiting) indispensable amino acid(s). An example is soy protein, which, in its native state, has insufficient methionine, but when fortified with methionine approaches or equals the overall quality of human milk protein (20).








TABLE 54.3 DIETARY REFERENCE INTAKES (mg/kg/d) OF ESSENTIAL AMINO ACIDS FOR INFANTS AND CHILDREN



























































AMINO ACID


0-6 moa


7-12 mob


1-3 yb


4-8 yb


Aromatic amino acids


120


61


46


38


Isoleucine


78


36


28


25


Leucine


139


71


56


47


Lysine


95


66


51


43


Sulfur amino acids


52


32


25


21


Threonine


65


36


27


22


Tryptophan


25


10


7


6


Valine


77


42


32


27


a Adequate intake.

b Recommended dietary allowance.


AIs of the essential amino acids for the 0- to 6-monthold infant are set at the amounts of each in the amount of human milk protein equal to the AI of protein. For the 7- to 12-month-old, 1- to 3-year-old, and 4- to 8-year-old child, EARs of the essential amino acids are based on the pattern of these amino acids in body protein and the EAR of protein. The AIs of the essential amino acids for the 0- to 6-month-old infant and the EARs of the older infant and young child are shown in Table 54.3.


Minerals

Calcium accounts for 1% to 2% of the weight of the adult, and approximately 99% of this is in teeth and bones. Accretion of calcium during infancy and early childhood ranges from 60 to 100 mg/day in children 2 to 5 years of age to 100 to 160 mg/day for those 6 to 8 years of age. Because percent absorption is quite variable, an AI obviously is important. The AIs of calcium set by the Food and Nutrition Board of the Institute of Medicine for the 0- to 6-month-old and 7- to 12-month-old infant are based, respectively, on the amount of calcium in the average intake of principally breast-fed infants and the average intakes of calcium from human milk plus complementary foods (3) (i.e., 210 and 270 mg/day, respectively). Calcium absorption of formula-fed infants is less than that of breast-fed infants, but the calcium content of formulas is higher; thus, calcium retention of breast-fed and formulafed infants differs minimally if at all. The AI of calcium for the 4- to 8-year-old child, 800 mg/day, is based on balance studies showing that an intake of 800 to 900 mg/day results in a mean calcium accretion of 174 mg/day. There being no similar balance data for the 1- to 3-year-old, the AI of this age group, 500 mg/day, is based on extrapolation from the AI of the 4- to 8-year-old child. Assuming 20% retention, this intake should result in accretion of approximately 100 mg/day.

The AI of phosphorus is 100 mg/day for the 0- to 6-monthold infant and 275 mg/day for the 7- to 12- month-old
infant (3). These values are based on the average intake of the 0- to 6-month-old breast-fed infant and the combined intake of breast milk and complementary foods of the 7- to 12-month-old infant. EARs of phosphorus were established for the 1- to 3-year-old and 4- to 8-year-old child, based on factorial estimates; these are 380 and 405 mg/day, respectively. RDAs (EAR × 1.20) are 460 and 500 mg/day, respectively.


Trace Minerals and Vitamins

DRIs have been established for all trace minerals except arsenic, boron, nickel, silicon, and vanadium, as well as for all vitamins (2, 4). These recommendations are summarized in Table 54.1. DRIs of major importance are iron, zinc, and vitamin D.

Although in theory the normal infant has sufficient stores of iron at birth to meet requirements for 4 to 6 months, iron deficiency during infancy is quite common. This probably reflects the marked variability in both iron stores and iron absorption among infants. Despite the low iron content of human milk, the Food and Nutrition Board of the Institute of Medicine set the AI of iron for the 0- to 6-month-old infant at the intake of iron by the principally breast-fed infant (4) at 0.27 mg/day. Moreover, the iron content of human milk is much more bioavailable than that of formulas. For this reason, only iron-fortified formulas are recommended. The EARs of iron for the 7- to 12-month-old infant, the 1- to 3-year-old child, and the 4- to 8-year-old child are based on a factorial approach accounting for obligatory losses as well as increases in hemoglobin mass, tissue iron, and storage iron. Assuming 10% bioavailability for the 7- to 12-month-old infant and 18% for the 1- to 8-year old child, EARs were set at 6.9, 3.0, and 4.1 mg/day, respectively, for the 7- to 12-monthold infant, the 1- to 3-year-old child, and the 4- to 8-yearold child. RDAs are 11, 7, and 10 mg/day, respectively.

Zinc is a component of as many as 100 enzymes with quite diverse functions (e.g., RNA polymerases, alcohol dehydrogenase, carbonic anhydrase, alkaline phosphatases). It also is important for the structural integrity of proteins and in regulation of gene transcription. Because of the participation of zinc in such a wide range of vital metabolic processes, symptoms of deficiency, even mild deficiency, are quite diverse. A primary feature of zinc deficiency is impaired growth velocity, which can occur with only modest degrees of restriction and circulating zinc concentrations that are indistinguishable from normal. Other features of zinc deficiency include alopecia, diarrhea, delayed sexual maturation, eye and skin lesions, and impaired appetite. Because of these diverse features of deficiency and the lack of reliable clinical or functional indicators of zinc status, adequate zinc intake is of primary importance.

As for other nutrients, the AI of zinc for the 0- to 6-monthold infants is based on the mean zinc intake of exclusively breast-fed infants (4). Because the zinc concentration of human milk falls from approximately 4.0 mg/L at 2 weeks postpartum to approximately 1.0 mg/L at 6 months postpartum, the AI, 2 mg/day, reflects an average intake of human milk of 0.78 L and a zinc concentration of 2.5 mg/L. EARs of zinc for the 7- to 12-month-old infant, the 1- to 3-year-old child, and the 4- to 8-year-old child are based on factorial analysis or extrapolation from the adult EAR, both of which are similar (2.5 mg/day for the 7- to 12-month-old infant and the 1- to 3-year-old child; 4 mg/day for the 4- to 8-year-old child). RDAs reflect a coefficient of variation or 10% (i.e., 1.2 × EAR).

The major function of vitamin D is to maintain serum calcium and phosphorus concentrations within the normal range by enhancing their absorption from the small intestine. Vitamin D is present in very few foods naturally; rather, it is synthesized from sterols in skin by the action of sunlight. Provided sunlight exposure is adequate, neither the breast-fed nor the formula-fed infant requires vitamin D. Some infants and children who live in northern latitudes or whose exposure to sunlight is otherwise limited (e.g., use of sun blocks or avoiding sunlight to prevent cancer; extensive clothing for religious or modesty reasons) may require supplemental vitamin D. The AIs established by the Food and Nutrition Board of the Institute of Medicine, 200 IU/day for the 0- to 6-month-old and 7- to 12-month-old infant as well as the 1- to 3-year-old and 4- to 8-year-old child, are based on the assumption that no vitamin D is obtained by exposure to sunlight (3). These intakes maintain normal serum 25-hydroxyvitamin D values and are not associated with evidence of vitamin D deficiency. Although available infant formulas provide as much as 400 IU/day, this amount is not thought to be excessive.


Water and Electrolytes

The AI of water for the normal infant is based on the average fluid intake of the predominantly breast-fed 0- to-6-month-old child (˜700 mL/day) and the average intake of human milk and complementary foods (including juices and other fluids) by the 7- to-12-month-old child (˜800 mL/day). However, because of higher obligate renal, pulmonary, and dermal water losses as well as a higher overall metabolic rate, the infant is more susceptible to development of dehydration, particularly with vomiting or diarrhea. Thus, provision of 150 mL/kg/day is often recommended.

Intakes of electrolytes by the breast-fed and formulafed infant as well as children between 1 and 8 years of age fed conventional foods, appear to approximate the DRIs of each (see Table 54.1).


FEEDING THE INFANT

The DRIs are for individual nutrients. However, these nutrients are not provided individually but rather as components of the diet. For the infant, who experiences
considerable growth as well as developmental advances, providing the foods necessary to meet specific needs for all nutrients sometimes can be challenging. Some of the most important issues in meeting this challenge are discussed in the sections that follow.


Breast-Feeding

One of the first decisions that must be made is whether the infant will be breast-fed or formula fed. In this regard, human milk is uniquely adapted to the human infant’s needs and hence is the most appropriate milk. In addition, it contains bacterial and viral antibodies that are thought to provide local gastrointestinal immunity against organisms entering the body by this route. These antibodies probably account, at least partially, for the lower prevalence of diarrhea as well as otitis media, pneumonia, bacteremia, and meningitis during the first year of life in infants who are exclusively breast-fed versus formula fed for the first 4 to 6 months of life (7, 8). Some evidence also indicates that breast-fed infants may have a lower frequency of food allergies and a lower incidence of chronic diseases in later life.

The psychologic advantages of breast-feeding for both mother and infant are well recognized. The mother is personally involved in the nurturing of her baby, thus resulting both in a feeling of being essential and a sense of accomplishment while the infant is provided with a close and comfortable physical relationship with the mother.

The first 2 weeks after birth are crucial for establishing successful breast-feeding. Daily weight gains of the infant, although important for ascertaining the volume of milk produced, should not be overly emphasized during this time. Further, supplemental bottle feedings to achieve weight gain may compromise attempts at breast-feeding and therefore should be limited.

Provided the mother’s milk supply is ample, her diet is adequate, and she is not infected with human immunodeficiency virus, no disadvantages of breast-feeding exist for the healthy term infant. Allergens to which the infant is sensitized can be conveyed in the milk, but the presence of such allergens is rarely a valid reason to stop breastfeeding. Rather, an attempt should be made to identify the offending allergen and remove it from the mother’s diet.

Maternal contraindications to breast-feeding also are few. Markedly inverted nipples may be troublesome, as may fissuring or cracking of the nipples, but the latter usually can be avoided by preventing engorgement. Mastitis also may be alleviated by continued and frequent nursing on the affected breast to keep it from becoming engorged, but local heat applications and antibiotics may be necessary occasionally. Acute maternal infection may contraindicate breast-feeding if the infant does not have the same infection; otherwise, no need exists to stop nursing unless the condition of either the mother or the infant necessitates it. If the mother’s condition does not permit breast-feeding, the breast may be emptied and the milk given to the infant by bottle or cup. Mothers with septicemia, active infections, or breast cancer should not breastfeed. Substance abuse and severe neuroses or psychoses may also be contraindications to breast-feeding.


Formula Feeding

Objective studies of growing infants less than 4 to 6 months of age show minimal, if any, differences in rate of growth, blood constituents, metabolic performance or body composition between breast-fed infants and infants fed modern iron-supplemented formulas. Thereafter, growth of the formula-fed infant usually is somewhat more rapid than that of the breast-fed infant. Such investigations attest to the ability of both breast milk and modern infant formulas to support normal growth and development of the infant. Thus, the mother who is unable or does not wish to nurse her infant need not have a lesser sense of accomplishment or affection for her baby than the nursing mother. Moreover, the quality of attachment and mothering as well as the degree of security and affection provided the infant need not be different with formula feeding versus breast-feeding. Further, the clear economic advantages and microbiologic safety of breastfeeding are of lesser importance for affluent developed societies with ready access to a clean water supply and refrigeration than for less developed and less affluent societies. Thus, a reasonable and conservative approach is to allow the mother to make an informed choice about how she wishes to feed her infant and support her in that decision. As stated by Fomon (21), “In industrialized countries, any woman with the least inclination toward breast-feeding should be encouraged to do so, and all assistance possible should be provided. At the same time, there is little justification for attempts to coerce women to breast-feed. No woman in an industrialized country should be made to feel guilty because she elects not to breast-feed her infant.”

Only gold members can continue reading. Log In or Register to continue

Jul 27, 2016 | Posted by in PUBLIC HEALTH AND EPIDEMIOLOGY | Comments Off on Nutritional Requirements of Infants and Children1
Premium Wordpress Themes by UFO Themes
%d bloggers like this: