Breastfeeding and It’s Role in Early Development of the Immune System in Infants: Consequences for Health Later in Life.
To prevent excessive, destructive, and adverse immunological reactions between mother and fetus that might lead to “immune abortion,” the immune system of the fetus is actively downregulated during pregnancy.
The immune system consists essentially of the innate immune system and the adaptive immune system. The innate immune system is the sum of physical barriers, chemical barriers, and the reactivity of local nonspecific cells and cells recruited to the site of inflammation. The innate nonspecific immune system is not fully developed or active in first year of life.
The skin and the respiratory and intestinal tracts all play pivotal roles in the innate immune response. In the latter 2 organs, the mucosal tissues form the physical and chemical barrier.
In infants, the integrity of the epithelial layer is not complete, as characterized by the existence of a higher permeability of the epithelial layer in both the respiratory and gastrointestinal tracts.
In adults, the creation of a low-pH environment in the stomach and the secretion of proteases and antipathogenic peptides are important features of the chemical barrier, inhibiting and killing invading pathogens. In infants, the secretion of these compounds is not fully developed.
Granulocytes comprise a subset of immune cells that play a crucial role in innate immune responses. It is known that neonatal neutrophils are reduced in number.
Because of the recent hygiene hypothesis, attention has been paid to the role of Toll-like receptors (TLR) in the immune response and immune development. TLR play an important role in sensing bacterial products and in activating and skewing the immune system.
After birth, a rapid activation of the acute-phase response is induced. The acute-phase response plays an essential role in the innate immune response. The brand of formula in question says it contains a “unique patented mix of special prebiotics” — sugars that are naturally found in milk and which are a source of food for so-called friendly bacteria (probiotics). Having a healthy mix of friendly bacteria in the gut is important for overall health because 80 percent of the immune system is located here, and the “good” bacteria can help to push out the “bad” bacteria that can cause disease.
Since breastfeeding is the biological norm, and since organs of the immune system like the thymus can only develop to their full potential through breastfeeding, an inevitable conclusion must be that people who were never breastfed (or those who were weaned too early) will have deficient immune systems — not just in infancy but for the rest of their lives.
From the outside, babies seem to grow well on formula — they certainly get bigger and longer. But on the inside their vital organs may struggle to grow adequately without support from mother’s milk, which has evolved to meet their needs. Perhaps one brand of formula can argue that it is marginally better than another brand, but can it possibly claim to be “inspired by breastmilk” or to “strengthen the immune system”? Those are claims that the real science simply does not support.