What is meant by milk? In the context of infant and childhood nutrition, the term “milk” refers to breast milk and infant formula in young babies (0-6 months). In older infants (> 6 months) and children, the term is also used to describe follow-on infant formulas and unmodified cow milk.

Breast milk is best for babies. The World Health Organization (WHO) recommends exclusive breastfeeding for the first six months of life. Breast milk supplies all the nutrients that a baby needs in this period – it is nutritionally complete. Breast milk also confers a level of immunological protection to the young infant. After six months of age, for nutritional and developmental reasons, a baby needs to have solid foods introduced to his/her diet but milk remains a very important food.

By “nutritionally complete”, we mean that breast milk provides all the nutrients in the right quantities to allow a young baby to grow and develop. These nutrients are as follows:

• Protein for growth and development – Casein and whey proteins.
• Carbohydrate for energy – Lactose, which is also known as milk sugar.
• Fat for energy.
• Vitamins, Minerals and Trace elements – These are important for a number of reasons and deficiencies can cause illness. A mineral that is particularly rich in milk and dairy products is calcium. Calcium is important for many reasons, especially the development of strong bones and teeth.

Breast milk also supplies other non-nutrient substances that are considered very important for the baby’s health.
Some mothers choose not to breastfeed. Others may breastfeed initially but then decide to stop after a few weeks or months. In such cases, standard infant formulas (baby milks) are typically used. These are based on cow’s milk.

Cow’s milk is very different to human milk however - it is more concentrated and levels of certain nutrients differ significantly from breast milk. As such, cow’s milk needs to be significantly modified to make standard infant formula.
Modern technology has allowed the production of infant formulas that are a good nutritional match to breast milk. As technology improves even more, scientists strive to make infant formula even more similar to breast milk but experts agree that breast milk will always be the best option for babies.

When a baby reaches the age of six months, unmodified cow’s milk is usually allowed into the diet. Initially it is mixed in with solid foods, but eventually (around the age of twelve months) it is allowed as a drink as breast milk and infant formula are gradually removed from the diet.