Home > Encyclopedia of Nursing & Allied Health > Infant Nutrition

Definition

Infant nutrition is the feeding behavior of an infant during the first year after birth.

Purpose

Due to the tremendous amount of growth during infancy, adequate nutrition after birth is essential for the development and nourishment of children. Proper nutrition can be obtained from the use of breast milk, infant formulas, and adequate diet related to age.

Precautions

When assessing the nutritional status of infants, it is important to consider the differences in the bodily functions of infants. The gastrointestinal functions of newborns are much slower than that of older infants, especially gastric emptying, which may account for the regurgitation, or spitting up, in newborns.

Passage through the small intestine is slower for infants, which helps ensure proper absorption and digestion of nutrients. However, the large intestine has a much faster transit time, which puts infants at an increased risk of dehydration if resorption of water and electrolytes is compromised.

The digestion of fat is also limited in infancy due to the decreased amount of pancreatic lipase, an enzyme secreted by the pancreas to digest fat. However, other lipases present in breast milk compensate for the lack of this enzyme and aid in fat digestion. Thus, the fat in human milk is more readily absorbed than the fat in prepared formulas.

Renal function is also limited in newborns because their kidneys are not fully developed until one month of age. The immature kidneys and other factors limit the newborns'ability to cope with fluid and electrolyte loads. Infants fed breast milk or properly prepared formulas normally do not have problems with renal solute load, although problems may occur with fever, diarrhea, or a reduction in the volume of fluids consumed.

Infants who sleep through the night may need to be woken up mid-way through the night to feed if they are underweight or not consuming enough. It is important to have routine check-ups with the doctor or dietitian to ensure that infants are eating adequately. Honey should also not be given to infants because it may contain spores that cause botulism.

Description

During the first six months of life, infants can receive adequate nutrition through either breast milk or fortified formula. An infant who is breastfeeding will need to nurse on demand or usually about eight to 12 times per day, while babies who are formula fed need to eat about six to eight times per day. In both breastfed and formula-fed infants, the number of feedings decreases as they get older, but the amount of milk the baby consumes at each feeding increases.

Prior to four months of age, an infant's digestive system has not developed well enough to tolerate solid foods. But at about four to six months of age, solid foods can start to be introduced into the infant's diet. It is important to look for signs that an infant is developmentally ready to handle solid foods. Once infants can hold their head up, sit up with minimal support, and begin to show an interest in food, solid feedings of iron-fortified baby cereal can be started. Mixing it with breast milk or formula to get a thin consistency is recommended until the infant can control its mouth better to handle a thicker consistency.

At six to eight months of age, the introduction of fruit juices and strained fruits and vegetables can begin. Use unsweetened juices that contain large amounts of vitamin C, such as orange, apple, or grape, but avoid putting an infant to sleep with a bottle of juice as this can lead to tooth decay. Introduce fruits and vegetables one at a time and wait a few days in between introductions to make sure the infant has no allergic reactions. Use plain fruits and vegetables such as carrots, squash, beans, bananas, applesauce, and pears. Introducing vegetables into the diet before fruits is often recommended because the sweet taste of fruit may make vegetables less appealing to the infant. Finger foods may also be introduced at this time, but avoid foods that may cause choking, such as grapes, hotdogs, nuts, and seeds. Breast milk or fortified formula should still be given about three to five times a day.

At eight to 12 months of age, an infant should still be receiving breast milk or formula three to four times a day, but also should start eating strained or finely chopped meat. Introduce different meat every week and include strained and ground meats and hotdogs. If eggs are given, only the yolk should be used until one year of age in case the infant is sensitive to egg whites.

If an infant still uses a bottle at one year of age, the bottle should only contain water, or whole (vitamin D) milk can be used instead of breast milk or formula. Lowfat milk should not be used until at least two years of age because infants need the extra calories for adequate development. Thereafter, no less than 2% milk should be fed to a young child.

Breastfeeding versus formula feeding

During the first year of life, breast milk is the best source of nutrition for infants. Breast milk provides several health benefits for both the mother and infant beyond the benefits of adequate nutrition. Nutritionally, breast

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KEY TERMS

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Antibodies—A naturally occurring protein in the blood that is produced in response to the toxicity of an antigen.

Botulism—A disease of the nervous system caused by eating spoiled foods.

Colostrum—Milk secreted for a few days after parturition that is characterized by high protein and antibody content.

Electrolytes—Compounds that form ions when they dissociate in water, such as potassium and chloride.

Enzyme—A protein catalyst that facilitates a reaction in the body without itself being altered.

Essential amino acids—Amino acids that cannot be made by the body.

Galactose—Monosaccharide that is part of the disaccharide lactose.

Glucose—Monosaccharide used for energy; also known as blood sugar.

Lactose—Disaccharide known as milk sugar.

Renal solute load—Amount of solution carried by the blood to the kidneys which is to be excreted through the urine.

Resorption—Absorb again.

Spores—Reproductive body of an organism that is capable of producing new individuals.

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milk provides the appropriate amounts of carbohydrate, protein, and fat for infants, along with essential vitamins, minerals, and digestive enzymes. It also provides antibodies that help increase the infant's immune system, decrease gastrointestinal distress, reduce the risk of allergy, and promote the development of the jaws and teeth. Colostrum is the milk secreted from the mother's breasts during the first few days after giving birth. This milk adequately provides the infant's needs during its first week of life as it is characterized by high protein and antibody content. For the mother, breastfeeding facilitates a faster recovery from labor, allows the mother to rest more often, and saves money that would have been spent on formula.

If breastfeeding is not the chosen method of feeding, iron-fortified formulas can be used to provide adequate nutrition. Infant formula has more protein and more iron than human milk, but it lacks antibodies. The American Academy of Pediatrics recommends that all formula-fed infants be given iron-fortified formula. Formula feeding also allows the mother to receive help with feedings and sleep more during the night. Formulas are available for infants who may have allergies to milk protein or are lactose intolerant. There are also formulas available for premature infants and those who have metabolism disorders.

Preparation

Improperly prepared formulas can be a very common cause of infant illnesses. When preparing formula, it is recommended that it not be mixed with warm tap water as this can increase the amount of lead in the formula, which can be very harmful to the infant. Bottles should also not be heated in a microwave because this could cause the milk to scald or the bottle to explode. Lastly, adding sweetened beverages or cereals to bottles should also be avoided because they will only displace the more nutrient-dense formula.

Complications

Most women are capable of breastfeeding as long as they allow their infant to nurse, although there are special circumstances when formula must be used instead of breast milk. Galactosemia is a rare genetic disease in which newborns lack the enzyme needed to convert galactose to glucose. Galactose is a component of lactose, which is very abundant in breast milk. Without the enzyme to convert it to glucose, galactose accumulates in the blood causing tissue damage and possibly death. Therefore, it is essential that these infants receive a lactose-free soy-based formula.

Phenylketonuria is another genetic disorder in which newborns lack the enzyme needed to convert the essential amino acid phenylalanine to the amino acid tyrosine. Accumulation of phenylalanine in the blood can cause severe mental retardation. Therefore, it is necessary to start a low phenylalanine diet with a low phenylalanine formula.

Health care team roles

The dietitian plays a very important role in educating parents on the importance of adequate infant nutrition and proper feeding methods. Dietitians are also responsible for informing people of the proper preparation of formula and the advantages and disadvantages of both breastfeeding and formula feeding. While caring for an infant, it is important to have routine check-ups with the doctor to check the infant's height and weight to ensure that the infant is at the right stage of growth and receiving adequate nutrition.

Lisa M. Gourley