The main components of breast milk are water, fat, proteins, lactose (milk sugar) and minerals (salts). Milk also contains trace amounts of other substances such as pigments, enzymes, vitamins, growth hormones, and antibodies. It is normal for breast milk to separate (the fatty part of the milk rises to the top).

Other facts about human milk:

• Fat content during a feed is determined by the fullness of the breast, not what you eat. The emptier the breast, the higher the fat content in the milk
• The longer time between feeding or pumping, the lower the initial fat content at the start of the next feed. The fat level at the start of one feed may not be the same as the fat content at the start of the next.  The longer the gap between feeds, the higher the water content and lower the fat content.
• Length of feed is irrelevant – some babies take a full feed in 5 minutes while others need 40 minutes to get the same amount. You can’t tell anything about fat content from the length of the feed.
• There are millions of live cells in milk, including immune-boosting white blood cells and stem cells, which may help organs develop and heal.
• Over a 1,000 proteins help baby grow and develop, activate the their immune system, and develop and protect brain neurons
• More than 200 complex sugars act as prebiotics in your milk, feeding ‘good bacteria’ in baby’s gut
• Enzymes are catalysts that speed up chemical reactions in the body. 40 different ones in your milk have jobs like helping baby’s digestion and immune system
• Growth factors that support healthy development. These affect many parts of your baby’s body, including her intestines, blood vessels, nervous system, and her glands, which secrete hormones.
• Hormones send messages between tissues and organs for them to work right. They help regulate baby’s appetite and sleep patterns
• There are 5 basic forms of antibodies in your milk, protecting baby against illnesses and infections by neutralising bacteria and viruses.