Chapter 13: Infant Feeding – Milk Composition, Formula, Weaning & Health

Human milk composition · Formula manufacture · Renal solute load · Milk consumption · Soya formula · Weaning (complementary feeding) · Weaning problems · Vitamin supplements · Dental health · Drinks & water · Pasteurized cow’s milk
📌 Core principles: Human milk provides optimal nutrition (fat, lactose, protein, IgA). Infant formula modified to resemble breast milk. Renal solute load lower in breast milk – formula increases risk of dehydration with fever/diarrhea. Weaning at 6 months with iron‑rich foods. Vitamin D for breastfed infants. Water not needed exclusively breastfed <6 months. Pasteurized cow’s milk not as main drink <12 months (low iron, high renal load).

📖 Core summary: milk composition, formula, weaning, dental health, drinks

🥛 Human milk composition
Macronutrients: fat (3‑5%), lactose (7%), protein (0.9‑1.2% – whey dominant). Immunoglobulins (IgA), oligosaccharides, lactoferrin, lysozyme, probiotics. Changes from colostrum to mature milk.
🏭 Manufacture of infant formula
Based on cow’s milk – demineralized whey, vegetable oils, lactose, vitamins, minerals. Heat treated (spray drying). Iron‑fortified (12 mg/L). Whey:casein ratio 60:40.
💧 Renal solute load (RSL)
RSL = solute load requiring renal excretion (protein, Na, K, Cl). Breast milk RSL low (8‑10 mOsm/100 kcal). Formula higher (30‑35). Cow’s milk very high – risk of dehydration with illness.
🍼 Milk consumption & soya formula
Infant intake 150 mL/kg/d. Soya formula used for galactosemia or CMPA if hydrolysed not tolerated. Contains phytoestrogens – not first line.
🥄 Weaning (complementary feeding)
Start at 6 months. First foods: iron‑fortified cereal, pureed meat, veg, fruit. Textures progress. Allergenic foods not delayed. Avoid honey (<1y), whole nuts, salt, sugar.
⚠️ Weaning problems
Feeding refusal, choking, gagging, constipation, food allergies (CMPA, egg, peanut). Iron deficiency anemia (late weaning, poor intake).
💊 Vitamin supplements & dental health
Vitamin D 400 IU/d (breastfed). Iron 1 mg/kg/d from 4‑6 months. Dental health: avoid bottle propping, sugar‑containing drinks, brushing with fluoride toothpaste from eruption.
💧 Drinks & water
Exclusively breastfed <6 months – no extra water needed. Formula fed – small amounts water if hot. Avoid fruit juice (<6 months). Pasteurized cow’s milk as main drink only after 12 months (low iron, high protein/renal load).
📊 Key differences: Breast milk lower protein, higher lactose, lower renal solute load, contains IgA. Formula higher iron (fortified), more consistent, higher renal load.

🔍 Clinical approach – feeding problems & weaning

1
Constipation after weaning – Increase fluid (water between feeds), high‑fiber purees (prunes, pears), avoid rice cereal if constipating. Review formula preparation.
2
Feeding refusal / picky eating – Rule out organic (GERD, CMPA, teething). Responsive feeding, no force, model eating, repeated exposure (10‑15 times).
3
Suspected cow’s milk protein allergy (CMPA) – Trial of hydrolysed formula; breastfeeding mother eliminate dairy. Symptoms: vomiting, diarrhea, blood in stool, eczema, poor weight gain.
4
Introduction of allergenic foods (peanut, egg) – No delay. Early introduction (4‑6 months) may prevent allergy, especially in high‑risk infants (eczema, family history).
5
Dental caries prevention – Avoid bottle at bedtime (except water), no sugar in bottles, brush with fluoride toothpaste (smear <3y, pea size >3y).

📋 Stepwise management – weaning, supplements, weaning problems

1
Weaning schedule (6 months) – Start with iron‑fortified single‑grain cereal mixed with breast milk/formula. Introduce pureed vegetables, then fruits, then meat. One new food every 3‑5 days.
2
Vitamin supplementation – Vitamin D 400 IU/day for breastfed infants. Iron 1 mg/kg/d for exclusively breastfed from 4‑6 months. Term formula fed no supplements (iron‑fortified).
3
Water intake – Exclusively breastfed <6 months: no extra water (breast milk sufficient). Formula fed: small amounts if hot weather or constipation. After 6 months, offer water with meals.
4
Pasteurized cow’s milk – Not as main drink <12 months (low iron, high protein, renal solute load). Can be used in small amounts in cooking after 6 months.
5
Soya formula indications
Galactosemia (absolute). CMPA if hydrolysed formula not tolerated or economic constraints. Not first line due to phytoestrogen concerns.
6
Dental health advice
Start brushing with fluoride toothpaste as soon as first tooth erupts (smear). Avoid sugary drinks, bottle propping. First dental visit by age 1.
⚡ Key reminder: Renal solute load is higher in formula and cow’s milk. During febrile illness, formula‑fed infants need extra water to prevent dehydration. Breastfed infants get all fluid from breast milk.

🧠 Reflex prompts – milk composition, weaning, dental health

🥛 Main protein in mature human milk?
Whey (60‑80%). Casein lower than cow’s milk. Easier digestion.
💧 Why is renal solute load important?
Higher solute load (formula, cow’s milk) increases risk of dehydration during illness (fever, diarrhea). Breast milk lowest.
🥄 Recommended age to start complementary feeding?
6 months (WHO). Not before 4 months.
💊 Vitamin D supplementation for breastfed infant – dose?
400 IU/day from birth.
🦷 When to start fluoride toothpaste?
With first tooth (smear of toothpaste). Pea‑sized at age 3.
🍶 Pasteurized cow’s milk as main drink – from what age?
12 months. Before that, use iron‑fortified formula.