Amino Acids

Feeding Amino Acids 9 essential amino acids = can’t be made by body If deficient in essential amino acids à negative nitrogen balance Maternal nutrition Low body mass and insufficient adipose à delays puberty & causes amenorrhoea Obesity also à decreased fertility Energy requirements increased by 200kcal / day During pregnancy expect to gain 12.5kgs wt Loose wt during lactation (increased fluid requirement – and will require 500kcal / day extra) Folic acid required as co-factor for DNA and protein synthesis. Deficiency à increased incidence of NTDs Nutritional Requirements – of INFANTS Fluid 150ml/kg/day (can be 200 in prems) 30mls = 1 oz 60mls à 90 à 120 à 150mls / kg / day If IUGR – then feed at 50th centile for gestation NOT actual body weight Inappropriate ADH is common in prems OR in term if lung / cerebral disorder à dilute serum & concentrated urine Treat by fluid restriction until diuresis Energy 100kcal/kg/day in term infant (120 if prem, 140+ if SGA) Carbohydrate = 40% of total energy requirement In human milk is 90-95% lactose (à glucose & galactose), small amount oligosaccharides Due to prem difficulty in lactose breakdown, prem formula is higher in glucose Fat Protein ½ of energy requirement 4-6g / kg / day Breast milk fat easier absorbed than cows milk Unsaturated fats > saturated absorption Medium chain fatty acids > long chain absorption Long chain polyunsaturated ? role in brain development – supplemented in prem formula 10% of energy requirement 2.5-3.5g/kg/day (increased in prem) Milk proteins are curds (casein) and whey (lactalbumin) Human milk more whey, cows = more curd Prems fed with formula high in casein can à metabolic acidosis from inability to excrete acids from protein metabolism Minerals & Trace elements Important for bone etc Iron Depletion occurs at 3m in prems & 5m in term infants (stores used up) Breast milk provides sufficient iron to 6m (even though 0.6ml/L at 2/52 and 0.3mg/L at 5/12) Prems – on either milk – should be supplemented Vitamins Fat soluble are stored well, water soluble can be lost with fluid Prems need vit D supplements to prevent rickets Breast fed babies are at risk of Vit K def therefore supplement at birth NB: Babies can lose up to 1oz/lb (up to 10%) of their bodyweight after birth Should regain within 7 days. Should gain 6oz a week (25 g/day = 175g/week) Feeding Very Low Birth Weight Infants LBW babies have more water & less protein & fat compared to term infants Should aim to gain 18g/kg/day from 24-28/40 16g/kg/day from 28-32/40 14g/kg/day from 32-36/40 Should be same balance as term infants re carb/fat & protein (NB 1g protein = 3.8kcal, 1g Carb = 3.8kcal, 1g fat = 10kcal Energy expenditure 50kcal = resting 15kcal = activity 10kcal = thermoregulation 10kcal = thermic effect from feeding 10kcal = faecal loss of energy 25kcal = storage (growth) = 120kcal/kg/day NB: if using TPN can exclude gut uses à 80-90kcal/kg/day Protein Prems lose 1.4g/kg/day of protein if only given IV glucose (because using protein breakdown to provide calories) Protein in EBM is insufficient alone for prem à fortifier Fats 0.5g/kg/day needed to prevent deficiency in fatty acids Deficiency à dermatitis, Thrombocytopenia, infection & FTT Give 3g/kg/day = extra used as calories Feeding Early introduction of feeds is beneficial for bowel adaptation, cholestasis etc BUT should be avoided for 5-7 days if high risk NEC (absent / reverse EDF) NG is preferable to NJ (higher death with NJ) No advantage of continuous over bolus Use TPN for shortest possible time Breastfeeding Only 21% of babies in UK are exclusively breast fed at 6 weeks, Only 1% are entirely breast fed at 6 months, and only 25% get any breast milk WHO advises entirely breast until 6 months & breast milk + food until 2yrs 67kcal / 100ml (54% fat, 40% carb, 6% protein, whey:casein = 0.7) Better absorbed due to smaller fat globules & human milk contains lipase Early breast milk contains high sodium & protein (as baby kidneys unable to retain Na) Lactose increases with age 90% of breast milk is taken in 1st 4 mins Preterm breast milk has even higher Na, Protein & IgA = more protection against NEC Establishing milk production During pregnancy ducts and alveoli in ducts multiply Placenta secretes lactogen à preparation for milk production Pituitary secretes prolactin à maintains milk production Suckling stimulates prolactin (anterior pituitary) and oxytocin (post pituitary) Oxytocin à let down response = milk ejection Feeding pattern 1st 24 hours = 3+ feeds Aim for skin-to-skin in 1st hour. 1st feed usually only 7mls 2nd 24 hours = 6+ feeds 10-20mls (each feed) 3rd 24 hours = 8-12 feeds 25-50mls (each feed) (in clusters) st End of 1 week= 70mls/feed. 5-35mins duration If baby opts to stop feed then offer the other breast Getting enough milk? Urine – 1 wet nappy for each day of age – 5-6/day by end of 1st week Stool – colour change (black à yellow mustard) Wt loss – as usual Constituents of Breast milk Carbohydrates as disaccharide (lactose) Fat as triglycerides and lipoproteins (based on mothers diet) Low protein (but easily digestible) as whey (lactalbumin, lactoferrin, lysozyme, IgA) Colostrum = early milk – rich in protein & cells, inc IgA, small volume Mature milk = diurnal variations in content. Risk of transfer of HIV, CMV & Hep B Advantages For mother – contraception, decreased anaemia risk, Decreased Ca Breast & ovary, & osteoporosis Aids wt loss, bonding, easy, free For baby Ideal Nutrients Anti-infective – Immunoglobulin = 90% IgA (high in colostrums), also IgG & IgM, Cells (B & T lymphocytes) Lysozyme (against e.coli) Lactoferrin (bins iron to stop bacteria multiplying – esp E.coli) Antiviral (bt IgA & interferon), Probiotics (bifidus factor = promotes growth of lactobacillus à metabolises lactose à lactic & acetic acid à decreased pH à inhibits bacterial growth) & lactobacilli à inhibits e.coli) Low allergy (lower risk of cows milk intolerance) Low SIDS, Lower risk of infant Type 1 DM, IBD, obesity & adult CVS disease. Intellectual advantage Premature babies fed formula have 20x risk of NEC than if fed breast milk Disadvantages Father unable to help, Embarrassment / fear, Difficult to monitor volume taken Contraindications Maternal health (untreated HIV), drugs (increased transfer if fat soluble, unionised, NOT protein bound, antihistamines, aminophylines, opiates & antidepressants, low molecular weight), Infant technical probs/food intolerance Formula Milks Infatrini Nutrini Nutriprem 2 Breast milk Neocate Pregestamil 100kcal/100mls 100 75 67 67 67 Modulen Galcomin 19 for crohns / IBD for glucose-galactose malabsorption fortified for prems for CMPI (or neutramigen / pepti junior) for galactosaemia / CMPI Cow’s milk NOT recommended in 1st 12 months Can transfer TB / Brucellosis if not treated Empties from stomach slower than breast milk Higher Curd:Whey ration than Breast milk Higher Iron than breast milk, BUT iron is absorbed better from breast milk High renal solute load Lack of Vit C & essential fatty acids High Ca, PO4, NA & K Cows milk protein intolerance Can be immediate hypersensitivity (test via skin prick) or delayed à diarrhoea & FTT Clinical diagnosis Usually self-limiting & resolves by 2 years old 20% will have / develop associated soy milk allergy Acute Sx should stop within 48 hours of milk withdrawal, chronic within 7d Caution needed if re-challenging infants Soy milk Increased aluminium Lower Ig levels Poorer response to vaccinations Neonatal Hypoglycaemia = failure of metabolic adaptation NO reliable Sx exist Changes to occur at birth IV (supply of glucose from placenta) to enteral Continuous to bolus Glucose to fat (majority of calories) Immature enzymes & hormone systems Concurrent CVS & RS adaptation At Birth Glucose supply stops Delay before insulin down-regulates = physiological hypoglycaemia (should recover by 3 hours) Brain & heart protected as ketones generated (by oxidation of FFAs) Brain needs 3.7mg/kg/min of glucose Body can supply 2.5mg/kg/min à therefore generates ketones Therefore not possible to define hypoglycaemia Safe levels (term babies) Hyperinsulinaemia (e.g. DM mum) > 3.3 (if insulin cannot generate ketones) Unwell baby >2.6mmol/l At risk, no Sx >2.0mmol/l Baby – Asphyxia, Infection, Rh disease Mum – DM, Labetalol, IV glucose NB: breast feeding stimulates ketogenesis à no need to check unless sx or at risk Preterm infants Less able to generate ketones therefore dependent on glucose Rx if BM < 2.0 IUGR If absent EDF / < 3rd centile / wasted appearance can be high risk as may have been hypoglycaemic in utero à cord glucose If cord glucose < 2.0 à start IV glucose straight away If Sx Increase feeds / IV Recheck If Sx not resolve then NOT due to hypoglycaemia If term baby then à ? hypopituitary / fatty acid oxidation disorder / hyperinsulin Further Ix required if: Term, well grown à severe hypo with seizures / coma At risk infants & Persistent / recurrent Resistant to > 10mg/kg/min of glucose Neuro Sx Acidaemia (include FH of SIDS / dev delay) Ix to do Metabolites Glucose Lactate 3-hydroxybutyrate Galactosaemia screen Hormones Insulin Cortisol GH Urine Organic acids Reducing substances Ketones Weaning Ideally breast feed for 6 months then start to introduce “complimentary feeds” e.g. baby rice etc Finger feeding at 12m Spoon feeding by 2y Knife & fork by 5 yrs Artificial Feeding Should allow feed to be taken within 15 mins – but not so fast that baby splutters Can be from bottle, spoon, cup or NG tube NB: cows milk is very high solutes and low in iron & vitamins Formula milk – decreases maternal milk supply as it keeps tummy full for longer, changes bowel flora, increases allergy and affects maternal confidence Functional gut Normal Absorption Long term support required à If no à TPN à If no à special formula (e.g. elemental) à If no à NG / NJ à If yes à enterostomy Risk of aspiration? à If no à gastrostomy à If yes à jejunostomy / gastrostomy + Nissen’s NB: bolus feeds stimulate GI hormones but continuous reduces aspiration risk TPN Lipid = fat + fat soluble vitamins Vamin = AA + Glucose + trace elements + ions + water soluble vitamins Need to provide minimum 1.5g/kg/day – aim for 3.5) Main indications in neonates Preterm <30/40 & < 1kg > 30/40 but unlikely to be on full feeds by day 7 Severe IUGR with abnormal dopplers NEC GI anomalies Administration Via central / long line Content Carb – mainly dextrose Protein – crystalline L amino acids Fats – high proportion of essential long chain fatty acids 1g/kg/day on day 1, 2g on day 2, 3g on day 3 and stay at 3g/kg/day Vitamins, minerals & trace elements – should be balanced Complications Infection – most commonly staph epidermidis Hyperglycaemia Metabolic disturbance Cholestatic jaundice – due to lack of hepatic stimulation if no enteral feeds Hyperammonaemia Lipaemia & fat accumulation in lungs – avoid by covering infusion & add Vit C Metabolic acidosis Venous thrombosis of long line site Tissue injury due to extravasation Decreased gut activity & therefore immunity from Peyers patches Neonatal feeding problems Vomiting Possets are common regurg of milk Vomits can be non-organic e.g. overfeeding, incorrect preparation of feeds, overstimulation of baby, crying & air swallowing Or organic e.g. infection, reflux, gastritis, hiatus hernia, bowel obstruction, pyloric stenosis, GI intolerance, food allergy Bilious vomiting is obstruction until proven otherwise. Also beware NEC Investigation – X-ray for obstruction, US for malrotation, Barium for reflux / hiatus hernia, urine microscopy & septic screen, stool cultures. pH probe & manometry Gastritis – can be due to swallowing of meconium / blood pre birth Reflux / Hiatus hernia – due to incompetent lower oesophageal sphincter (esp. if prem or neuro prob) delayed emptying & poor oesophageal contractility, Occurs mainly at end of feed / during winding. Can à structure, failure to thrive, SIDS (due to apnoea), aspiration. Treat by head up, antacids, thickeners etc Pyloric stenosis – rare to occur before 1/12, can occur in 1st week. Colic Constipation Diarrhoea – check maternal diet, formula make-up, infection, intolerance & CF Failure to thrive – should double birth wt by 5m & triple by 1y NUTRITIONAL REQUIREMENTS OF CHILDREN Carbohydrates 4 Kcal/g Starch à amylase Sucrose à sucrase Lactose à lactase Disaccharide digestion occurs on the brush border. Uptake of sugars is dependent on Na cotransport Some carbs pass to intestine à colon à fermented into short chain fatty acids Some starch will also pass into colon (e.g. unripe banana, raw potato) Protein Fats Meat, dairy and cereals Amino acids required for growth Denatured by gastric acid (& pepsinogen à pepsins) + pancreatic protease Brush border uptakes amino acids and di/tri peptides Synthesised back into proteins in the liver Excess cannot be stored à de-aminated à urea à excreted by kidneys 9 Kcal/g Meat, Milk, Fish, Fried foods Mostly ingested as triglycerides Pre-duodenal lipase in stomach + pancreatic lipase + bile salts à emulsifies to droplets Micelles enter enterocytes Free-fatty acids à carrier proteins Required for cell membranes and neuronal development Teenagers Rapid growth & brain development Gain 50% of adult wt and skeletal mass + 20% of adult height during puberty Nutritional requirements in disease May need increased intake if increased losses (e.g. D&V), failure of digestion/absorption (e.g. CF, celiac) or increased energy requirements (e.g. CP) IBD Induce and maintain remission Need to increase calories + Fe, Folate, B12 and Zn Elemental feeds aid absorption and can help with remission CF 85% have pancreatic insufficiency. Increased appetite but low wt gain, increased requirements and losses) Give 150% of estimated calorie requirements and CREON and ADEK Coeliac Exclude gluten PKU (Phenyl-ketonuria) Dietary restriction of phenylalanine (excess metabolites damages developing brain) although need a small amount as cant be synthesised. Aim for levels 3-15mg/dl Diabetes 55% carbs (70% complex), 30% fat, 15% protein Neuordisability Consider chewing & swallowing probs May require PEG VITAMIN DEFICIENCIES Vit A = Xerophthalmia à Blindness, photophobia, keratoconjunctivitis, xeropthalmia Vit A found in dark green leafy veg Vit C = Scurvy Connective tissue disorder à bleeding from capillaries + poor healing Presents with painful periosteal bleeds or persistent superficial haemorrhages Vit D = Rickets Found in fish, eggs, butter, margarine & from sunlight – mother needs high levels Vit D aids Ca2+ absorption and bone formation Deficiency à Softening & deformity (esp. in long bones) Newborn craniotabes (soft skull) 3-6month rachitic (rosary enlargement of rib ends) 12-18month bowed legs Excess vitamin D Sx similar to hypercalcaemia Decreased tone, anorexia, irritability, constipation, polydipsia, polyuria, pallor Increased Ca in blood & urine à metastatic calcification Dehydration, aortic stenosis, vomiting, raised BP, retinopathy & clouding of cornea & conjunctiva 2o rickets Due to processing defects in Vit D pathway or renal defects à excess loss Vit K = bleeding Low Vit K in breast milk à all babies have Vit K injection @ birth Otherwise present @ 7 days with bleeds from mouth, umbilicus & bowel B12 = Cobalamin Deficiency à pernicious anaemia B6 = Pyridoxine Deficiency à irritable with convulsions (co-enzyme for Fatty acid metabolism) Pyridoxine (Vit B6) dependent seizures Usually present in new-born period High doses needed to control fits EEG normalises within 2-6 mins Vitamin E deficiency Common in malabsorption & body stores deplete quickly Peripheral neuropathy with haemolytic anaemia & acanthocytes Cerebellar signs develop later Can get retinitis pigmentosa if replacement is inadequate Thiamine Deficiency à Polyneuritis & cardiac failure Beri-Beri (endemic in some parts of world) Hoarse cry due to paralysis of laryngeal nerve Pseudomeningitis with irritability, vomiting and seizures Can get “wet form” with high output cardiac failure Chromium Needed for glycaemic regulation & insulin metabolism Found in Yeasts Deficiencies Fluorine à dental caries Niacin à pellagra Biotin à dermatitis & seborrhoea Copper à refractory anaemia, neutropenia, depigmentation, ataxia & osteoporosis Selenium à Keshian cardiomyopathy, muscle weakness & arthritis (cofactor for glutathione peroxidase Marasmus Emancipation but reasonable appetite Born undernourished / severe illness / twins with insufficient milk Survival relies on maintaining feeds & prognosis good if food available Kwashiorkor Protein & calorie deficiency Symptoms mainly due to low protein (low intake / abnormal loss) due to infection / synthesis failure Usually presents at weaning à Muscle wasting with fat preservation Marasmus à Apathy, irritable, inadequate growth, loss of muscle, increased infections, oedema (low albumin) à Secondary immune deficiency à Fatty infiltration of the liver & failure to thrive & cardiomegaly à Darkening of the skin (due to low Zn), sparse thin hair (can be red of grey) à Chronic infections à anorexia, vomiting & chronic diarrhoea à Coma & death Encourage continuation of breast feeding & give high protein weaning foods Treatment with iron early in the disease can make it worse Obesity Kwashiorkor BMI > 95TH centile Can be assoc with syndromes e.g. Prada-willi (+ short stature etc) Increased risk of DM, SUFE, high BP, varicose veins, piles + skin crease problems. Also depression & truancy. Increased risk Ca Breast, Kidney & prostate Poor healing & poor outcome from heart & lung pathology Prevention – don’t enforce plate clearance. If high risk wean late, aim for regular exercise & small frequent meals Treatment Diet & exercise regime à increasing self esteem Assess for underlying psych problem (depression etc) Orlistat = pancreatic lipase inhibitor à steatorrhoea Surgery if BMI > 40 or > 35 + comorbidity Sibutramine = anti-satiety agent, now withdrawn due to increased risk of MI & CVA