Breast Milk Increases Infant Immunity

Babies are born with immature immune systems. An important function of breast milk is to support the development of the infant’s immune system. Breast milk enables the baby to build a stronger immune system for life.

Every human being carries different types of bacteria in the body, specifically the gastrointestinal tract, called darmflora (or gut flora). These bacteria are necessary for the continuation of normal life. About three-quarters of an individual’s immune system is located in an individual’s intestines.

As soon as the baby is born, bacteria settle on the skin, in the intestines, oral cavity, nasal cavity, and the upper respiratory tract. It is the safest for these bacteria to come from the mother’s milk, since it contains components that will assist in suppressing the immune response against these good bacteria, which help the body protect itself from potentially harmful bacteria and other pathogens outside the body. It is important to introduce the baby’s immune system to various kinds of pathogens so that it can learn to recognize these threats. The immune system grows by exposure to germs. And if a pathogen remains in the intestine and is not transmitted to the blood, a baby’s cells will memorize it.

Breast milk contains several substances that attack pathogens and prevent an infant’s inflammatory reactions (fever, swelling, decreased appetite, etc.) to them. Inflammatory reactions occur because pathogens enter the bloodstream and infect the tissues. Breast milk coats the intestinal wall, stimulates its maturation, and prevents the absorption of these pathogens. Breast milk also contains certain antibodies that neutralize toxins that are excreted by some pathogens once they enter the body.

As mentioned above, several compounds in breast milk attack intestinal pathogens. The best known and most important of these are the antibodies (immunoglobulin A, or IgA). These antibodies are of a different type than the antibodies that protect a baby in the womb (IgG). The antibodies in breast milk are mainly active in the intestines and on the mucous membranes, while the antibodies that protect the baby in the womb (IgG) come into action as pathogens enter the blood and the tissues. Antibodies from human milk attach themselves to the intestine to protect against bacteria and viruses. Thus, pathogens are prevented from penetrating the blood and causing inflammatory reactions. The antibodies are adapted from breast milk to fight a variety of pathogens, namely all that the mother has ever been in contact with. Antibodies also neutralize toxins excreted by certain pathogens.

Breast milk contains lactoferrin, an iron-binding protein that helps obtain iron from human milk in such a way that it reduces the amount of iron available in the intestine. An iron-rich environment is favorable for harmful bacteria. Lactoferrin also plays a role in fighting pathogens. It weakens the cell walls of harmful bacteria, after which lysozyme, another protein, can destroy the bacteria. Lactoferrin appears to stimulate the growth of certain beneficial bacteria strains. It also inhibits the production of pro-inflammatory messenger substances, which reduces the risk of inflammatory response.

Breast milk also contains many living white blood cells that act as pathogens that swallow and destroy. These cells do some good things, however, since their main function is to protect mammary gland tissue. The mother's immune cell uptake that generally occurs during breastfeeding ensures that the baby learns the tissues of the mother's body; it is much more likely for a breastfed child to better accept a kidney donation from the mother than the father.

Breast milk contains fats that are degraded to fatty acids by enzymes in the baby’s digestive tract. These fatty acids inhibit the growth of various pathogens. Breast milk also contains more than 90 different types of long sugar chains. These attach themselves to the pathogen, which is then prevented from entering the bloodstream.

Immune cells have to learn their job and build memory of infections so they can be recognized and fought quickly. This “ripening” of the immune cells occurs in the thymus, an organ that can be found above the heart. Non-breastfed children have a thymus that is half the size of that of breastfed infants. A larger thymus means more immune cells and a better functioning immune system. In developing countries, a baby's chance of survival is directly related to the size of the thymus.

Breast milk contains copies of pieces of pathogen informatiom (anti-idiotype antibodies). A vaccine is a safe version of a pathogen, so this substance is a harmless replica that the body to make memory cells directed against a specific pathogen. Breastfed babies’ optimal immune response after vaccination is directly related to the anti-idiotype antibodies in breast milk.

The growing immune systems of young children need many nucleotides, which are building blocks of DNA (genes) that are located in every cell of the body. Breast milk contains a large number of these nucleotides. Lactation affects the bacterial composition (the microflora or intestinal flora) present in the baby's gut. The growth of harmless bacteria is stimulated significantly, which improves the infant’s overall intestinal health, for life in some cases.

Please note that much of the information in this article is based on Dr. Lars A. Hanson’s Immunobiology of Human Milk.

Are you a new mother who is embarking on the breastfeeding journey? Are you having trouble with, or are you worried about, breast milk production? You’ll definitely want to check out this wonderful natural product that is guaranteed to boost your milk production.