Infant Nutrition

Milk provides all the nutrients needed by newborn infants for the first 6 months of life. Breast milk is the ideal milk for human babies, but formula milk may be needed as an alternative in some cases. The newborn infant has high calorie and fluid requirements and to achieve optimal growth requires approximately 150 mL/kg per day of fluid and 110 kcal/kg per day (462 kJ/kg per day). About 40% of this energy comes from carbohydrate (mostly lactose) and 50% from fat. Milk also contains protein in the form of casein, lactalbumin and lactoferrin. Colostrum is the thin yellow milk produced in the first few days which is high in immunoglobulins.

Infants also require adequate amounts of minerals such as calcium and phosphate, as well as vitamins and trace elements. Breast milk is deficient in vitamin K, and so all newborn infants are given vitamin K at birth to prevent haemorrhagic disease of the newborn. Weaning on to solids usually starts around 6 months, and infants should not have cow’s milk until they are over a year.

The stool pattern of breast-fed babies differs from that of bottle-fed babies. They have non-offensive, porridge-consistency, yellow stools, initially after each feed. The frequency then reduces so they may have only one per week without being constipated.

Technique of Breast-Feeding

Mothers should be encouraged to put their babies to the breast soon after delivery. Little milk is produced but the suckling stimulates lactation. Colostrum is produced in the first days, which is rich in energy and anti-infective agents. It is important that the baby is taught to ‘latch on’ to the breast properly with a widely open mouth, so that the areola and not just the nipple is within the baby’s mouth. The majority of the milk is taken by the baby in the first 5 minutes. Time after this is spent in non-nutritive suckling. Mothers can feel their breast ‘emptying’. Babies should not be pulled off the breast, but the suck released by inserting a clean finger at the side of the baby’s mouth. Each feed should start on the alternate breast.

In the first few days the breasts may become painfully engorged with milk and the nipples sore, especially if the baby’s position is not optimal. Mothers need a lot of encouragement and advice to get through this time.

It is important to try to avoid alternating breast and formula feeds. Formula feeds should only be introduced if breast-feeding is contraindicated or has failed completely. It is not appropriate to ‘top up’ with formula or use bottles to give the mother a rest. This may help in the short term but leads to tailing off of milk production and breast-feeding failing altogether.

Weaning

Current recommendations are to start weaning at 6 months of age. Generally cereals, rusks or rice-based mixtures are introduced first, mixed with expressed breast milk or formula milk. This semi-solid mixture can be given by spoon before milk feeds. Puréed fruit or vegetables are also suitable. Modern baby cereals are gluten-free, which may be associated with a fall in the incidence of coeliac disease (see p. 000). As the child grows older the feeds can become more solid and are given as three meals a day. From 7 to 9 months they will enjoy finger-feeding themselves and can chew on rusks or toast. From about 9 months they can generally eat a mashed or cut-up version of adult food. Undiluted full-fat pasteurized cow’s milk can be given from 1 year of age. An earlier introduction of cow’s milk or the persistence of exclusive breast-feeding can lead to iron deficiency. Vitamin supplements may be needed from 6 months in breast-fed babies, until they are on a full mixed diet.

Nutrition in the Preschool Years

As a toddler the child becomes more adept at holding a spoon and can feed independently, and can drink from a beaker or cup. Milk is no longer the main source of nutrients, although the child should still drink a pint a day. Whole-fat milk should be used until age 5 years to provide plenty of calories, unless the child is overweight. A well-balanced diet should include food from the four main groups:

• Meat, fish, poultry and eggs
  
• Dairy products (milk, cheese, yoghurt)
  
• Fruit and vegetables
  
• Cereals, grains, potatoes and rice.

In order to avoid dental caries and obesity it is important to avoid frequent snacking on sugary foods or drinks—three meals and two snacks is recommended, although this may be adapted to the individual child. Iron-deficiency anaemia (see Chapter 47) is common at this age, due to high requirements for growth and poor dietary intake, especially in the ‘faddy eater’. Vitamin C present in orange juice can enhance iron absorption from the gut.

Nutrition in the School-Age Child

At school, children have to learn to eat food outside the family setting. They usually have a midday meal, and fruit or milk may be provided at break times. The principles of healthy eating should be maintained, although peer pressure to eat crisps or sugary snacks is often high. Schools have an educational role to play in encouraging healthy eating and a healthy lifestyle. During adolescence there is a greater energy requirement to allow for increased growth. This may coincide with a lifestyle that leads to snacking and missing meals, or to restrictive dieting or the over-consumption of fast food. Obesity and eating disorders often have their onset around this time.