What Are the Substances That Inhibit Bacterial Growth in Human Milk?

Human breast milk is free, convenient, and nutritious. Breast milk has special components that boost a baby's immunity and protects against infections caused by various germs, such as those caused by bacteria.

Immunoglobulins

• Breast milk contains human immunoglobulins, or antibodies whose levels increase with maternal exposure to specific germs. Levels are especially high in the first three to five days after a baby is born. Some antibody levels remain high in the milk during a nursing baby's first year.

Lysozyme

• Breast milk contains high amounts of a digestive enzyme called lysozyme, which affects the types of bacteria in a baby's digestive tract, encouraging the growth of beneficial bacteria.

Growth Factors

• Breast milk contains growth factors that boost levels of lactobacillae, which prevents infection by harmful bacteria. Infants fed formula have lower levels of lactobacillae.

Lactoferrin

• Lactoferrin, a protein that binds iron, is also found in breast milk. It encourages healthy bacteria in the gut and acts as an antibiotic for E. coli and staphylococci. Lactoferrin levels remain high in the milk during the first year of a nursing baby's life.

Vitamins and Minerals

• Human breast milk contains the appropriate vitamins and minerals for human babies to develop strong bodies and immune systems to resist all types of infections. The milk changes and adjusts to the baby's needs as it grows.