Infant Nutrition and Special Nutritional Needs of Children PDF

Infant Nutrition and Special Nutritional Needs of Children Prof. Ibrahim Al-Adham Dr.Dania Alhyari Taken from Handbook of Nonprescription Drugs 1 Human Milk Human milk is most physiologically suited to infants and is the optimal...

Infant Nutrition and Special Nutritional Needs of Children Prof. Ibrahim Al-Adham Dr.Dania Alhyari Taken from Handbook of Nonprescription Drugs 1 Human Milk Human milk is most physiologically suited to infants and is the optimal milk source for feeding infants until 12 months of age. It is recommended to use human milk as the sole source of nutrition for infants during the first 6 months of life. For infants whose mothers choose not to breastfeed, the nutritional quality, safety, and convenience of infant formulas make them an appropriate alternative A health care provider should be able to provide information to parents or other caregivers to encourage successful breastfeeding. This service requires knowledge of infant and child nutrition needs, breastfeeding, and commercially prepared infant and pediatric formulas, including differences in formula composition and specific uses for therapeutic formulas. 2 Gastrointestinal Maturation By the end of the second trimester of pregnancy, all segments of the fetus’s GI tract are formed and display some physiologic function. The third trimester, however, is the period of maximal GI tract growth and differentiation. Therefore, premature infants (those born before 37 weeks gestation) often have reduced GI tract function, especially those born prior to 32 weeks gestation. 3  Unabsorbed lactose that enters the colon undergoes bacterial fermentation (colonic salvage) to short chain fatty acids, which creates an acidic environment that favors growth of acidophilic bacterial flora (lactobacilli) and suppresses growth of more pathogenic organisms. This acidity also promotes water absorption and prevents osmotic diarrhea. Because of the relative abundance of glucoamylase, compared with lactase, in the premature infant’s intestine, glucose polymers are digested and absorbed better than lactose. Newborns exhibit low pancreatic lipase concentrations and slow rates of bile acid synthesis, both of which are important for fat absorption. 4  Infants born earlier than 34 weeks gestation, however, may exhibit steatorrhea (i.e. the excretion of abnormal quantities of fat with the faeces owing to reduced absorption of fat by the intestine) Maturation of the kidney is also important in nutrition, because it determines the ability of the kidney to excrete a solute load. After birth, the rate of glomerular filtration increases until growth stops, toward the end of the second decade of life. 5 Growth Birth weight is determined primarily by maternal prepregnancy weight and pregnancy weight changes. The average birth weight of a term infant is approximately 3500 grams. Premature infants are categorized on the basis of birth weight: Low birth weight infants weigh less than 2500 grams Very low birth weight infants weigh less than 1500 grams Extremely low birth weight infants weigh less than 1000 grams Micropreemies weigh less than 750 grams. 6 Infant Nutritional Standards FDA sets specifications for minimum amounts of 29 nutrients and maximum amounts of 9 of those nutrients. Components of a Healthy Diet Infants require the same dietary components as adults: fluid, carbohydrates, proteins, fats, and micronutrients. However, the desired proportion of these components in the infant diet differs. Fluid Water is an important part of an infant’s diet, given that it makes up a larger proportion of the infant’s body weight than in older children or adults. 7 8 Carbohydrates Under normal circumstances, an infant can efficiently use a diet with 40%-50% of total calories from a carbohydrate source. Carbohydrate intake should be balanced with adequate fat intake to allow proper neurologic development. Children with seizures may receive an essentially carbohydrate free diet, the ketogenic diet, because these metabolic effects may facilitate seizure control. 9 Lactose Lactose, the primary carbohydrate source in human milk and most milk based formulas, is hydrolyzed to its monosaccharide components, glucose and galactose, by gastric acid and lactase. Congenital lactase deficiency is a rare type of lactose intolerance resulting from an inborn error of metabolism. Infants born prematurely, prior to the maturation of significant lactase activity (before approximately 36 weeks gestation), are relatively lactase deficient. 10 Lactase Secondary lactase deficiency is a temporary reduction in intestinal lactase caused by gastroenteritis or significant malnutrition. Because of low lactase activity, infants with congenital lactase deficiency, premature infants, and infants recovering from diarrhea or severe malnutrition may be unable to completely metabolize the quantity of lactose found in human milk or milk based infant formulas. Lactose intolerance symptom in diarrhea, abdominal pain or distention, bloating, gas, and cramping. 11 Protein and Amino Acids The protein’s amino acid composition (i.e., chemical value) is also important. Amino acids are classified as essential (or indispensable), nonessential, conditionally essential. The amino acids cysteine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, tyrosine, and valine are considered essential for infants because the human body cannot synthesize them from other amino acid and carbohydrate precursors. 12  Taurine is an especially important amino acid in infancy. Quantities in human milk are high, and all infant formulas are supplemented during the manufacturing process to provide the same margin of physiologic safety as that provided by human milk. Taurine is not an energy source and is not used for protein synthesis, but it serves as a cell membrane protector by attenuating toxic substances (e.g., oxidants, secondary bile acids, and excess retinoids) and acting as an osmo regulator. Taurine deficiency can result in retinal dysfunction, slow development of auditory brain stem evoked response in preterm infants, and poor fat absorption in preterm infants and children with cystic fibrosis. 13 Fat and Essential Fatty Acids Fat is the most calorically dense component in the diet, providing 9 kcal/g compared with 4 kcal/g for both protein and carbohydrates. Fat accounts for approximately 50% of the nonprotein energy in both human milk and infant formula. Infant feeding practices, especially fat and calorie intake, are increasingly being linked to obesity and other diseases (e.g., diabetes and cardiovascular disease) in adulthood. Despite these concerns, children younger than 2 years (the time of most rapid growth and development requiring high energy intakes) should not receive a fator cholesterol restricted diet unless medically prescribed. Children between 12 months and 2 years who are at increased risk for cardiovascular disease (CVD) because of a family history of obesity, dyslipidemia, or CVD may be candidates for reduced fat milk products. 14  Fat and Essential Fatty Acids children between 2 and 5 years of age should adopt a diet that contains 20%-30% of total calories from fat, with less than 10% of calories from saturated fats and less than 1% from trans fatty acids. The diet must also contain small amounts of the two essential polyunsaturated fatty acids (PUFAs): linoleic acid, an omega 6 (n6) fatty acid, and linolenic acid, an omega3 (n3) fatty acid. Linoleic acid represents the bulk of PUFAs in infant formulas. These fatty acids are precursors for the n3 and n6 long chain PUFAs: docosahexaenoic acid (DHA) and arachidonic acid (ARA), respectively. 15 Micronutrients Infant formulas are supplemented with adequate amounts of vitamins and minerals to meet the needs of most term and premature infants when the appropriate formula is chosen. 16  Infant Food Sources Human milk and cow milk-based formulas are the primary food sources for most infants. Soy protein based formulas and goat milk are alternatives. 17  Human Milk It is recommend that infants be breastfed without supplemental foods or liquids for approximately the first 6 months (i.e., exclusive breastfeeding). It is reinforcement of breastfeeding and human milk as the reference normative standards for infant feeding and nutrition and reaffirmation of the recommendation to exclusively breastfeed for 6 months, followed by continued breastfeeding for 1 year or longer as mutually desired by mother and infant. Cow Milk Cow milk is the primary nutrient source for commercially prepared milk based infant formulas. 18 Average Composition of Mature Component Whole Cow Milk Mature Human Milk Human and Whole Cow Milk Water (mL/100 mL) 87.1 87.2 Protein (g/100 mL) 0.9-1.3 3.3-3.4 Whey:casein ratio 72:28 18:82 Alphalactalbumin (g/100 mL) 0.3 0.1 Alphalactoglobulin (g/100 mL) -- 0.4 Lactoferrin (g/100 mL) 0.2 Trace Secretory IgA (g/100 mL) 0.1 Trace Albumin (g/100 mL) 0.04 0.04 Fat (g/100 mL) 3.9 3.4-3.8 Carbohydrate (g/100 mL) 6.77 4.7-4.8 Minerals Calcium (mg/L) 200-280 1200 Phosphorus (mg/L) 120-140 960 Calcium:phosphorus ratio 2:1 1.3:1 Sodium (mg/L) 120-250 500 Potassium (mg/L) 400-550 15-60 Chloride (mg/L) 400-450 10-20 Magnesium (mg/L) 30-35 120 19 Average Composition Component Mature Human Whole Cow Milk of Mature Human Milk Vitamin A (international units/L) Vitamins 2000 1000 and Whole Cow Milk Thiamin (mcg/L) 200 300 Riboflavin (mcg/L) 400-600 17-50 Niacin (mg/L) 1.8-6 0.8 Pyridoxine (mg/L) 0.1-0.3 0.5 Pantothenate (mg/L) 2-2.5 3.6 Folic acid (mcg/L) 80-140 50 Biotin (mcg/L) 5-9 35 Vitamin B12 (mcg/L) 0.5-1 4 Vitamin C (mg/L) 80-100 17 Vitamin D (international units/L) 22 24 Vitamin E (international units/L) 2-8 0.4-0.9 Trace Minerals Chromium (mcg/L) 45-55 20 Manganese (mcg/L) 3 20-40 Copper (mg/L) 0.2-0.4 100 Zinc (mg/L) 1-3 3.5 Iodine (mcg/L) 150 80 Selenium (mcg/L) 7-33 5-50 Iron (mcg/L) 400 460 Fluoride (mcg/L) 4-15 -- 20 Whole Cow Milk Whole cow milk is not suitable for providing nutrition to infants younger than 1 year. Because of the low concentration and poor bioavailability of iron, whole cow milk has been associated with iron deficiency anemia Sensitivity to dietary proteins, most commonly cow or soy milk proteins, can manifest as occult GI bleeding, further increasing the risk of anemia. Milk protein intolerance and/or allergy can also result in rash, wheezing, diarrhea, vomiting, colic, and anaphylaxis when whole cow milk is used. When whole cow milk is fed with solid food, infants receive unnecessarily high intakes of protein and electrolytes, resulting in a high renal solute load (RSL) 21 Reduced Fat Cow Milk Reduced fat cow milk has been advocated to prevent obesity and atherosclerosis as part of a “healthy diet.”, such as skim milk (0.1% fat), lowfat milk (1% fat), reduced fat milk (2% fat), However, when the low fat diet recommended for adults is imposed on children younger than 2 years, it puts them at risk for failure to thrive and impaired neurologic development. Reduced fat milk is not recommended during episodes of diarrhea because of the possibility of hypertonic dehydration. It is not recommended to use of low fat diets during the first 2 years of life, except for children between 12 months and 2 years with a family history of CVD. 22 Evaporated Milk Evaporated milk is a sterile, convenient source of cow milk with standardized concentrations of protein, fat, and carbohydrate. However, it is not recommended for infant feeding. Goat Milk Although goat milk is the primary milk source for more than 50% of the world’s population Goat milk is commercially available in powdered and evaporated forms. It contains primarily medium and short chain fatty acids; therefore, the fat is more readily digested than the fat in cow milk. Unfortified goat milk is not recommended during infancy because it is deficient in folate and low in iron and vitamin D. The evaporated form of goat milk, however, is supplemented with vitamin D and folic acid. Powdered goat milk is supplemented with only folic acid; therefore, it is recommended only for children older than 1 year. Because the powder formulation is not a complete formula, vitamin supplementation is required if it is used for infant nutrition. 23 Commercial Infant Formulas - Milk Based Formulas Milk based formulas are prepared from nonfat cow milk, vegetable oils, and added carbohydrate (lactose). The added carbohydrate is necessary, because the ratio of carbohydrate to protein in nonfat cow milk solids is less than desirable for infant formulas. The most widely used vegetable oils are corn, coconut, safflower, sunflower, palm olein, and soy. Replacement of the butter fat with vegetable oils allows for better fat absorption. Therapeutic Formulas Various therapeutic formulas, including soy protein based, casein based, casein hydrolysate based or whey hydrolysate based, and low electrolyte and low mineral formulas. Formulas intended for use by premature infants and those formulated specifically for children from 1-10 years of age are also considered therapeutic formulas. 24  Pre thickened Milk Based (e.g. AR) This formulas were developed specifically for infants with gastroesophageal reflux. These iron fortified formulas contain rice starch. Before ingestion, the viscosity is much lower than a standard infant formula thickened with rice cereal. Therefore, these formulas flow better through a nipple than standard infant formula thickened with rice cereal. Once ingested, however, the viscosity increases dramatically in the stomach’s acidic pH, reaching a viscosity equal to the combination of standard infant formula plus rice cereal. This effect may be minimized in infants receiving a histamine 2 receptor antagonist (e.g., ranitidine or famotidine) or proton pump inhibitor (e.g., omeprazole, lansoprazole, or esomeprazole) for treatment of their gastroesophageal reflux, if the gastric pH is greater than 5.4. it is recommended for use in premature infants because neither will adequately meet their needs, especially for protein, calcium, and phosphorus. 25  Soy Protein Based Formulas. Soy protein based formulas contain a soy isolate fortified with l-methionine;none contain lactose. Soy formulas are a safe and nutritionally sound alternative for normal growth and development in infants who are not fed human milk, who do not tolerate cow milk based formula, or whose parents choose them for other reasons (e.g., vegetarians). However, because soy formulas have insufficient amounts of calcium, phosphorus, and vitamin D in relationship to some infants’ increased needs, they are not recommended for patients weighing less than 1800 grams. Food allergy occurs in infants because the immature digestive and metabolic processes may not be completely effective in converting dietary proteins into non- allergenic amino acids. 26 Soy Protein Based Formulas. Cow milk protein allergy occurs in 2%-3%of infants and is defined as symptomatology involving: the respiratory tract (wheezing), skin (rash), or GI tract (diarrhea and bloody stools) disappearing when cow milk is removed from the diet and reappearing on two separate challenges when cow milk is re-introduced during a symptom free period. Symptoms of cow milk protein intolerance generally regress within 3-4 years in most children. Soy protein based formulas are appropriate for infants with lactose intolerance resulting from lactase deficiency and with documented immunoglobulin E (IgE) mediated allergy to cow milk protein. In addition, soy protein based formulas are not recommended for infants with cystic fibrosis, because these children do not use soy protein adequately, will lose substantial nitrogen in their stools, and will develop hypo-proteinemia or even anasarca (generalized infiltration of fluid into subcutaneous connective tissue). infants with cystic fibrosis do well nutritionally when given an easily digested formula that contains semi-elemental protein and medium chain triglycerides 27 (MCTs) (e.g., a casein hydrolysate based formula). Casein Hydrolysate Based Formulas (hypoallergenic) Protein is supplied by enzymatically hydrolyzed, charcoal treated casein rather than by whole protein in casein hydrolysate based formulas, These formulas are classified as semi-elemental and contain non-antigenic polypeptides with molecular weights less than 1200 daltons; therefore, they can be fed to infants who are sensitive to intact milk protein. Casein hydrolysate based formulas are supplemented with l-cysteine, l-tyrosine, and l- tryptophan, because the concentrations of these amino acids are reduced during the charcoal treatment. 28 Whey Hydrolysate Based Formulas. Enzymatically hydrolyzed whey protein is another protein source used in infant formulas. Infants who have GI intolerance to cow milk but are not allergic to it often tolerate whey hydrolysate based formula. This product is promoted as having a pleasant taste, smell, and appearance. It may be better accepted than casein hydrolysate based formulas, which parents and infants find differ noticeably from cow milk and soy protein based formulas in both appearance and taste. 29 Amino Acid Based Formulas. Occasionally, infants are intolerant to even hydrolyzed casein and require a free amino acid based formula. Neocate Infant contain 100% free amino acids and are considered hypoallergenic. They are used for infants with cow milk protein allergy, multiple food protein allergies, or intolerance to casein hydrolysate formulas. 30 High mediu mchain triglycerides (MCT) Formulas. They are unique formulas because of their high MCT content. They also contain higher concentrations of both lipid and water soluble vitamins than are found in casein hydrolysate based formulas. The higher concentrations of MCTs and vitamins in these formulas help compensate for the impaired digestion and absorption of long chain fats in patients with pancreatic insufficiency (e.g., cystic fibrosis), bile acid deficiency (e.g., biliary atresia or cholestatic jaundice), and intestinal resection. Another use is to decrease lymphatic flow in patients with lymphatic anomalies such as chylothorax (i.e. a type of pleural effusion due to either disruption or obstruction of the thoracic duct) and chylous ascites (i.e an accumulation of lipid-rich lymph in the peritoneal cavity due to disruption of the lymphatic system secondary to traumatic injury or obstruction). Children with fat malabsorption who receive this formula can develop essential fatty acid deficiency. Linoleic acid (e.g., corn or safflower oil, or Microlipid) can be given in the diet, either by mixing with the formula or by syringe through a feeding tube, to prevent essential fatty acid deficiency. 31 Low potential renal solute load (PRSL) Formulas. an infant formula with lower mineral (potassium and phosphorus) and protein (1.5 g/100 mL) content, and therefore lower PRSL than standard infant formulas. It is most appropriately used for infants with renal insufficiency. It may also contains less calcium and iron than standard infant formulas; supplementation of these minerals may be necessary. 32 Preparation of the formula - note the failure to properly dilute a concentrated infant formula can result in a hypertonic solution that could result in diarrhea and dehydration. In extreme cases, the ingestion of an overly concentrated formula can lead to hypernatremic dehydration (induced by water deficit), metabolic acidosis, and renal failure. Excessive formula dilution can lead to water intoxication that can result in irritability, hyponatremia, coma, brain damage, or death. 33