INFANCY

Overview

• The content covers infancy, focusing on nutrition, growth, and development during the first year of life.

Definition of Terms

• Acid urine: Normal waste product from the breakdown of purines.
• Gastric acidity: Release of acid into the stomach from glands in the stomach walls.
• Pancreatic lipase: Enzyme that hydrolyzes triacylglycerol substrates to split dietary fats.
• Bile acid: Steroid acids found in bile.
• Water intoxication: Increase in free water volume in the body.
• Hyponatremia: Lower than normal concentration of sodium in the blood.
• Rickets: Softening and weakening of bones in children, typically due to vitamin D deficiency.
• Erythropoiesis: Process of making red blood cells.
• Negative Iron Balance: Body iron content declining due to decreased iron intake or increased iron losses.
• Dental Fluorosis: Opaque spots or streaks on tooth enamel due to excessive fluoride intake.
• Metabolites: Substances formed or necessary for metabolism.
• Renal Solute Load: Solutes of endogenous or dietary origin requiring excretion by the kidneys.
• Necrotizing Enterocolitis: Serious and fatal disease with abdominal distention, tenderness, gastric residuals, and bloody stools.
• Newborn Screening: Procedure using the heel prick method to test for congenital disorders.
• Heel Prick Method: Taking blood drops from a baby's heel for newborn screening.
• Palmar Grasp: Immature way of holding an object using the palm.
• Pincer Grasp: Refined way of holding an object using fingers.

Characteristics of a Normal Full-Term Infant

• Rapid growth occurs during the first year.
• Birth weight doubles in the first 4-6 months and triples by the end of the first year.
• Infants' length increases by 50% during the first year and doubles by age 4.

Body Fat

• Increases rapidly during the first 9 months, then tapers off.

Body Water

• Decreases from 70% at birth to 60% at 1 year due to a decrease in extracellular water.
• After one year, intracellular water accounts for 60%, and extracellular water accounts for 40% of total body water.

Kidneys

• Functionally immature but gradually increase in size and capacity to concentrate urine.
• Ability to form acid urine develops.

Stomach

• Capacity increases from 20-30ml at birth to 200ml by 1 year, enabling less frequent but larger meals.
• Gastric acidity decreases during the first few weeks of life.

Fat Absorption

• Human milk and commercially prepared infant formulas are well-absorbed.
• Younger infants lose a higher percentage of fat intake in feces than older infants.
• Pancreatic lipase activity is low.
• Bile acid pool is reduced compared to adults.

Bile-Stimulated Lipase

• In human milk, it hydrolyzes triglycerides into fatty acids and glycerol.
• Lingual and gastric lipases hydrolyze short & medium chain fatty acids, while gastric lipase also hydrolyzes long chain fatty acids.

Enzymes

• Enzymes that digest disaccharides reach adult levels by 28-32 weeks of gestation.
• Salivary and pancreatic amylase remain low during the first months of life.
• Salivary amylase rises to adult levels between 6 months to 1 year.

Nutrition Allowances

• Rapid growth requires an adequate supply of all essential nutrients.
• Factors influencing nutrient requirements: age, gender, body size, rate of growth, physical activity, basal energy expenditure, and reserves acquired in utero.
• Infants need over twice as much of many nutrients per unit of body weight compared to adults.

Energy

• Provides fuel for body functions, activity, and growth.
• Requirement is very high per unit of body size in the first few months of life.
• Basal metabolic demand may be higher due to greater heat loss from a larger body surface area and proportion of metabolic tissue.
• Adequacy of energy intake is best evaluated by the growth rate in length & weight.

Protein

• Supplies amino acids for new tissue synthesis and nitrogen for tissue maturation.
• Needed for tissue replacement.
• First 4 months: 3.5g/day.
• Next 8 months: 3.1g/day.
• Protein needs decline as growth decreases.
• Essential amino acid needs differ between infants and adults; histidine is essential for infants; tyrosine, cystine, and taurine are essential for premature infants.

Protein Sources

• Human milk is the major adequate protein source during infancy until the first 6 months.
• After the first 6 months, the diet (for breastfed infants) should be supplemented with high-quality protein such as strained meats or cereal mixed with milk.

Protein Inadequacy

• Factors for intake inadequacy:
  • Poverty
  • Excessive dilution of formula
  • Continuation of a regimen designed to treat diarrhea after enteric illness
  • Multiple food allergies
  • Extreme vegetarianism
• Inexpensive high-quality protein sources: peanut butter, whole wheat bread sandwiches, beans and rice, eggs.

Fat or Lipid

• Should supply 40-50% of the energy consumed during infancy, needed as a concentrated calorie source for rapid growth & development.
• Human milk, cow's milk, and commercially available formulas provide about 50% of the energy as fat.
• Linoleic acid is essential for growth and dermal health and should provide 4-5% of the total calories consumed.
  • Human milk: 4%
  • Infant formulas: 10%
  • Cow's milk: 1%

Carbohydrate

• Should supply 30-60% of the energy consumed during infancy.
• No specific recommendation for dietary intake of glucose since it can be synthesized from amino acids & glycerol.
• Energy is obtained from lactose and other carbohydrates.
  • Human milk: 37%
  • Commercial formula: 40-50%
• Other important sources are sugars and complex carbohydrates.

Water

• An essential component of body structure and a solvent for minerals and other physiologically important compounds.
• Transports nutrients to cells and waste products from cells.
• Aids in body temperature regulation.
• Requirement for an infant is determined by the amount of water lost from the skin, lungs, feces, and urine.

Water Balance

• Infants can dehydrate very rapidly.
• Fluid exchange rate is seven times greater compared to an adult.
• Metabolic rate is two times greater relative to body weight.
• Infants are vulnerable to water imbalance due to greater demand for insensible water loss and less renal concentrating ability.
• Adequate water requirements are met by consuming adequate amounts of breast milk or infant formula for the first 6 months of life.

Water Sources

• Human milk and properly prepared infant formula can supply adequate amounts of water.
• Boiled human milk or infant formulas are not appropriate since the water evaporates and solutes become concentrated.
• Infants may need more water in hot environments.
• Monitoring of fluid electrolyte imbalance is required if an infant has diarrhea or vomiting (when there is insensible fluid loss).

Water Intoxication

• May result in restlessness, nausea, vomiting, diarrhea, polyuria or oliguria, and hyponatremia.
• May arise if water is fed as a replacement for milk, formula is excessively diluted, or bottled water instead of an electrolyte solution is given for diarrhea.

Vitamins

• Vitamin requirements are determined by intakes of energy, protein, and other nutrients.
• Vitamins function in a variety of metabolic processes that make protein synthesis and energy metabolism possible.

Vitamins in Breast Milk

• Breast milk from healthy lactating mothers can supply all the vitamin needs (for full-term babies) except vitamin D, which only contains 40-50 IU/L.
• Vitamin D supplement or exposure to sunlight is needed.
  • Fully clothed without hat: 2 hrs/week.
  • Wearing diaper only: 30 minutes/week.
• Rickets are often seen in breast-fed infants with dark skin and little exposure to sunlight.
• Lactating mothers on strict vegetarian diets may have vitamin B12 deficient milk (if followed for a long time before and during pregnancy).

Vitamins in Infant Formula

• These formulas are fortified with all the necessary vitamins.
• Evaporated and homogenized cow's milk contains Vitamin D but very little Vitamin C.
• Fresh goat's milk is deficient in Vitamins C & D, and folate.
• Reports have shown deficiencies in formula-fed infants due to nutrients being destroyed or omitted during milk processing, or manufacturer's failure to add vitamins destroyed during processing.

Vitamin K Deficiency

• Hemorrhagic disease of the newborn is more common among breast-fed infants (breast milk contains 15mcg/L of Vitamin K; formula and cow's milk contains four times more).
• Breast-fed infants consume less milk during the first few weeks of life, accounting for their low Vitamin K intake.
• Suggested Vitamin K intake for infants is 15mcg/day (this amount can be supplied only by mature breast milk).

Minerals

Calcium

• Levels of plasma calcium & phosphorous fall significantly during the first 2-3 days of life.
• The decline is greatest for formula-fed healthy full-term infants and least for those who consume human milk.
• Plasma calcium levels stabilize after the initial decline and tend to rise by the 10th day.
• Calcium level depends on the calcium/phosphorous ratio of milk.
• Serum calcium concentrations are greater in breast-fed infants than in formula-fed infants.
• The body of a full-term infant has been estimated to contain about 27g of Calcium.
• Formula-fed infants retain 25-30% of calcium in cow's milk.
• Breast-fed infants ingest less calcium (240mg in 750ml milk) but retain approximately two-thirds of intake.

Iron

• Needed to maintain hemoglobin (Hb) and increases iron mass due to growth in body size.
• Iron deficiency is a common nutritional deficiency and occurs when body iron is diminished, which, when prolonged, eventually leads to iron deficiency anemia.

Iron Deficiency Anemia

• Signs of anemia may appear after 12 months of age; deficiency may start with inadequate iron nutrition during the first year of life.
• Normal infants have adequate iron stores for up to 4 months.
• Recommended iron intake:
  • First 6 months: 6mg/day.
  • After 6 months up to 3 years of age: 10mg/day.

HB Concentration

• Hb concentration in the blood at birth averages 17-19g/100ml and then declines to 10-11g/100ml during the first 6-8 weeks.
• This decline is caused by the shortened life span of fetal cells and decreased erythropoiesis.
• A gradual increase in Hb concentration is observed after the said age of decline (13g/100ml at 2 years of age).

Iron in Milk

• Breast-fed infants are at risk for negative iron balance starting 4-6 months, which may deplete their reserves by 6-9 months.
• Both breast-fed and formula-fed infants should take iron supplementation such as iron-fortified cereals.
• Iron status of infants fed whole milk is less satisfactory than those fed breast milk or infant formulas.

Zinc

• Normal infants do not have zinc reserves and are therefore dependent on dietary sources.
• Better absorbed from human milk compared to infant formulas.
• Both human and formula milk provide adequate zinc, which is 0.3-0.5mg/kg body weight during the first year of life.

Fluoride

• Essential for the prevention of dental caries.

• Intake levels of 4-1000mg/day can cause dental fluorosis.

• Breast milk has very low fluoride content, while powdered formulas have higher concentrations (compared to concentrated formulas).

• Commercially prepared infant cereals, wet pack cereals, and fruit juices produced from fluoridated water are good sources of fluoride.

• No fluoride supplementation is recommended for infants younger than 6 months of age.

• After tooth eruption, fluoridated water is recommended to be offered to breast-fed infants, those receiving cow's milk, and those fed formulas (which are made with water that contains less than 0.3mg fluoride/L).

Nutrition Assessment

Pediatric Growth Charts

• Used by pediatricians, nurses, other allied health professionals, and parents to track the growth of infants, children, and adolescents.
• Tools that contribute to forming an overall clinical impression of the human being measured.
• They are not intended to be used as a sole diagnostic instrument.

Has 4 types of assessment:

• Anthropometry
• Biochemical assessment
• Dietary assessment
• Clinical examination

Anthropometry

• Anthropometric measurements assess physical size and growth.:

  • Weight
  • Length
  • Head circumference

• Scales used to weigh infants:

  • Balance beam scale (pan type)
  • Seating scale

• Length measured in the recumbent position on a measuring board with a fixed headboard and movable footboard.

• Recorded as the distance between the headboard and the footboard when the infant has been positioned properly.

• Two persons are required to measure the length of an infant.

• Should be measured to the nearest 0.1cm (or 1/8 inch).

• Head circumference confirms that growth is proceeding normally or helps detect protein-energy malnutrition; evaluates the extent of its impact on brain size.

• A non-stretchable tape is placed around the largest part of the infant's head, just above the eyebrow ridges, just above the point where the ears attach, and around the occipital prominence at the back of the head.

Biochemical Assessment

• Assessment of iron status using Hb or hematocrit determination is the most useful biochemical test for measuring the nutritional status of infants.
• For infants who are in their 6th to 24th month of age, anemia is defined as an Hb concentration of less than 11g/dl or a hematocrit of less than 33%.

Dietary Assessment

• Food intake data provides information on the adequacy of an infant's diet; it can be used to develop plans for resolving concerns about food and nutrient patterns.
• With the large variety of methods that can be used to collect dietary data (which each one having their limitations and varying degrees of reliability), the most common methods used are the 24-hr food recall, food record, and food frequency.
• The interview is the most important aspect of dietary assessment; the validity of the information depends on the parents' understanding of the purpose of the interview being conducted, the information being sought, the parent's comfortability with the interview and the interviewer, and the interviewer's skill in probing and validating information being collected.

Clinical Examinations

• Common physical signs of malnutrition may require more extensive and efficient assessment thru clinical examinations that are conducted in clinics, hospitals, and other medical institutions.

Feeding a Normal Full-Term Infant

• Breast-fed Infant
• Formula-fed Infant
• Unmodified Cow's Milk
• Foods for Infants

Breast-fed Infant

• Breast milk is the best food for the infant because its composition is designed to provide the necessary energy and nutrients in appropriate amounts.
• The composition of human milk is different from cow's milk and is, therefore, not recommended for an infant's consumption until 1 year of age.

Composition Differences of Breast Milk & Cows Milk

• Energy: Breast Milk and Cow's milk both provide 20 kcal per ounce.
• Protein Breastmilk - provides 6-7% of energy while Cow's milk provides 20%.
• Whey: Breast Milk - 60% while Cow's milk provides 20%.
• Casein: Breast Milk- 40% while Cow's milk provides 80%.
• Amino acid (Taurine and Cystine): Breast Milk- in higher concentrations, Cow's milk provides in lower concentrations.
• Lactose: Breast Milk - provides 42 % of energy while Cow's milk Cow's milk provides 30% of energy.
• Lipids: Breast Milk - Provides 50 % of energy while Cow's milk provides 50% of energy.
• Oleic Acid: Breast Milk - predominant fatty acid.
• Linoleic acid: Breast Milk - provides 4 % of energy.
• Arachidonic acid (ARA): Breast Milk - present while Absent in Cow's milk.
• Docosahexaenoic acid (DHA): Breast Milk- Present while absent in Cow's milk
• Cholesterol: Breast Milk: 747m/d while Cow's milk provides 10-35mg/dl
• Vitamin B-complex: Breast Milk- adequate amount while Cow's milk provides adequate amount.
• Vitamin C: Breast Milk- adequate amount while Cow's milk provides insufficient amount.
• Vitamin A Breast Milk - adequate amount. Cow's milk - breast milk is higher.
• Vitamin E: Breast Milk-is a richer source (2 IU/L) compared to cow's milk
• Vitamin D: Breast Milk Small amounts while Cow's (fortified with 400-IU/L)
• Iron Absorption Breast Milk - 49 % of Iron is absorbed compared to Cow's milk less Iron absorption.
• Zinc bioavailability -breast milk is higher compared to cow's milk
• Contains factors that provide protection against certain bacteriologic infections, diarrhea, and otitis media.
• Human milk and colostrum contain antibodies and anti-infective factors which are not present in cow's milk; these factors are responsible for the lower incidence of infections among breast-fed infants.
• Secretory immunoglobulin (IgA), the predominant immunoglobulin in breast milk, plays a role in protecting the infant's immature gut from infections.
• Lactoferrin, the iron-binding protein in human milk, deprives the bacteria of iron and therefore slows down bacterial growth.
• Lysozyme, a bacteriolytic enzyme found in human milk, destroys the cell membranes of bacteria after they have been inactivated by the peroxides and ascorbic acid found in human milk.
• Breast milk enhances the growth of Lactobacillus bifidus that produces an acidic gastrointestinal environment and interferes with the growth of certain pathogenic organisms.
• Allergic reactions to human milk are relatively rare.
• The intestines of a newborn are permeable to large molecules.
• Secretory IgA promotes closure of the gut and decreases permeability of allergens.
• B-Lactoglobulin & albumin, the cow's milk protein, are the most common allergens in infancy.
• The closeness between the mother and newborn during breast-feeding facilitates attachment and bonding.
• Skin contact during breast feeding wherein the infant is held and cuddled facilitates bonding or attachment of both the mother and her child.
• Providing milk to feed her newborn can be a favorable experience for the mother and child as this promotes maternal involvement and interaction.

Breast feeding

• Breastfeeding is advantageous to both the mother and the child.

The first six months

• The mother should be encouraged to nurse her infant immediately after birth.
• Infants should be held or cuddled during feeding whether breast or formula-fed.
• Once a feeding rhythm is established, infants will become fussy or cry when feeling hungry or smile & fall asleep when satisfied.
• Infants should establish their feeding schedules.
• At first: most infants feed at intervals of 2-3 hours.
• At 4 weeks: most extend the feeding intervals to 4 hours.
• At 2-4 months: sufficient maturation has occurred to omit the night feeding.
• Human milk should be used as the ONLY source of food for the first 4-6 months.
• The introduction of solid foods may lead to a decrease in breast milk intake and early weaning.
• WHO recommends that supplementary feeding be given at 6 months of age.

After the first six months

• Breastfeeding should be continued up to one year of age.
• Solid foods should be introduced.
• Cereals, fruits, and vegetables are introduced first; hard-cooked eggs and cooked dried beans such as munggo and peanuts follow this at 7 months.
• At 8 months: fish, liver, meat, and poultry may be added.
• Cereals fortified with iron may be consumed to supplement the iron needed by the infant.
• Infants should be offered foods that contain vitamin C to aid in improving iron absorption; examples of good sources of vitamin C are fruits and vegetables.
• Frequent feeding at mealtimes helps children become familiar with a variety of flavors and textures, leading to acceptance of other foods.
• High-fiber foods such as cereals and raw vegetables should not be fed in large quantities since they are bulky and low in calories.
• Meat and milk products are good sources of protein and minerals for bone and muscle development.

Examples of first foods to be introduced:

• Cereals: rice porridge, oatmeal, boiled rice
• Fruits: banana, papaya, mango, avocado
• Vegetables: leafy greens and yellow vegetables

Supplementary Feeding Guide

Recommended Vitamins & Mineral Supplementation for Full Term Infants

• Iron:
  • Breast-fed infant: About 1 mg/kg/day by 4-6 months of age, preferably from supplemental foods.
  • For breast-fed infants younger than 12 months: only iron-fortified formulas for weaning or supplementing breast milk.
  • Formula-fed infants: only iron-fortified formula during the first year of life.
• Vitamin D:
  • An intake of 400 IU daily is recommended; most formulas provide 62 IU/100 to meet this recommendation. Adequate sun exposure for 30 min/week if clothed in diaper only or 2 hrs/week if fully clothed (no hat).
• Vitamin K:
  • Supplementation soon after birth to prevent hemorrhagic disease the newborn.
• Fluoride:
  • 0.25 mg/day after 6 months if the water supply is less than 0.3 ppm

Formula-Fed Infant

• Commercial formulas made from heat-treated non-fat milk are designed to:
  • Provide the necessary nutrients in a well-absorbed form and approximate closely the composition of human milk.
• Mothers unwilling or unable to breast-feed should feed their babies with infant formula based on cow's milk or soy product.
• The use of iron-fortified formulas has caused the declining prevalence of anemia in infants.
• Commercial formulas are available in ready-to-feed form, as concentrates, and in powder form.

Nutrient Levels in Infant Formulas Based on the Infant Formula Act (US FDA)

• The US Food and Drug Administration (FDA), through the Infant Formula Act, regulates the manufacturing of infant formulas.

Selected Nutrient Composition Levels (Per 100 kcal)

• Soy-based formulas are available for infants who cannot tolerate cow's milk-based formulas; this formula is recommended for:
  • infants of vegetarian families
  • infants with galactosemia or primary lactase deficiency, as well as those recovering from secondary lactose intolerance
  • infants who are potentially allergic to cow's milk but have not shown clinical manifestations of allergy
• Infants fed with said formula grow as well as and absorb minerals at a rate similar to infants fed cow's milk-based formula.
• A concern regarding soy formulas is the greater exposure of infants to phytoestrogens or isoflavones compared with breast milk or cow's milk-based formula, but the significance of this elevated level on infant development is not yet understood.
• For infants who cannot tolerate soy products, they can use formulas made from casein hydrolysate.

Good Sanitation Practices (For Preparing Commercial Infant Formulas)

• No need to sterilize the formula (in the majority of households with good sanitation practices).
• All equipment such as bottles, nipples, spoons, measuring cups, and top of can should be thoroughly washed.
• The infant should be fed right after the formula is prepared, and milk not consumed should be thrown away.
• Opened cans of formula should be covered and stored in the chiller or refrigerator.

Unmodified Cow's Milk

• Not recommended for an infant's consumption in their first year of life due to the presence of tough and hard curd that develops on this specific milk; this curd is difficult for the infant to digest, and a lesser amount of fat is absorbed compared with human milk.
• Has a much higher protein and ash content that can lead to a higher renal solute load; the ingestion of goat's milk may result in an even higher renal solute load.
• Infants on cow's milk-based formulas are found to have lowered intakes of iron, linoleic acid, and vitamin E and excessive intakes of protein, calcium, phosphorous, sodium, and potassium.

Problems Encountered on infants who were introduced with unmodified cow's milk before one year of age.

• Iron-deficiency anemia
• Chronic constipation
• Anal fissures
• Low fat and non-fat milks are also inappropriate for infants until 2 years of age.

Foods For Infants

• A variety of commercially prepared foods for infants are widely available in the market, including ready-to-serve infant cereals (that are iron-fortified), strained and junior vegetables & fruits, strained and junior meats, and dessert items such as puddings & fruit desserts.
• Mothers or parents can make their own baby food; home-prepared foods are more concentrated in nutrients compared with commercial foods because less water is used.
• Salt should not be added to home-made baby foods; sugar should be used sparingly.

Infant and Adult Food Labels

• Different serving sizes are based on average amounts that infants under 2 years usually eat at one time.
• The total fat content shows the amount of total fat in a serving of food and does not list calories from fat, saturated fat, and cholesterol.
• Percentage daily values are listed for protein, vitamins, and minerals.

Infant's Development of Feeding Skills

• Infants at birth can coordinate sucking, breathing, and swallowing; they are also prepared to suck liquids but not foods with texture.
• During the first year, normal infants develop head control, the ability to move into and sustain a sitting position, the ability to grasp (first with a palmar grasp & then with a pincer grasp), develop a mature suck and rotary chewing, and progress from being fed to feeding themselves using their fingers.
• Palmar Grasp - The ability to intentionally grasp an object in the palm and wrap the fingers around it.
• Raking Grasp - The ability to intentionally use their fingers to "rake" an object in the palm of their hand
• Inferior Pincer Grasp - The ability to pick up small objects between the pads of their thumb and forefinger.
• Superior Pincer Grasp - The ability to pick up small objects between the tips of the thumb and forefinger.
• Developmental readiness and nutrient needs are the criteria used to determine appropriate times to add various foods.
• During the first 4 months, the infant attains head & neck control, and oral motor patterns change from a suck to a suckling to the beginnings of a mature sucking pattern; pureed foods are consumed in the same manner as liquids, with each suckle followed by a tongue-thrust swallow.
• At 4-6 months, the mature suck is refined; munching movements or up & down chopping motions start to manifest; during this stage, it is relevant to introduce strained foods such as cereals and a variety of home-prepared foods.
• It is crucial to introduce foods one at a time to identify allergies to certain foods; infants gradually increase their acceptance of new foods by increasing the amount they eat.
• As oral-motor maturation proceeds, rotary chewing develops, showing a readiness for more textured foods such as mashed vegetables; learning to grasp shows readiness for finger foods such as toast or biscuits.
• During the last quarter of the first year of life, babies can approximate their lips to the rim of the cup and can drink if the cup is held for them; by their second year, they can rotate their wrists and elevate their elbows so they can hold the cup by themselves.
• They may be messy feeders at first, but by the age of 2, most children become skillful self-feeders.
• The infant's interest in food changes as they mature, and their growth slows down.
• Between 9-18 months, most reduce their milk intake and become finicky on what and how much to eat; in the weaning stages, infants learn manipulative skills such as chewing, swallowing of solid foods, and use of utensils; they learn to eat a variety of food (with different textures and flavors), to finger feed, then help themselves.
• Food should be easy to handle & eat; meats, raw fruits & vegetables should be cut into bite-sized servings (vegetables can be mashed); utensils (cups & dishes) should be small & manageable; serving sizes should be kept in proportion to their age.
  • 1 Tbsp of each food for each year of age
  • At 1 year of age, babies eat 1/3 to 1/2 the amount an adult normally consumes
  • By 3 years of age, this has increased to half of an adult portion or a little more
  • By 6 years of age, this has increased to 2/3 the amount of an adult portion

Weaning

• The introduction of solid foods into an