This may be off center some but I've three daughters. My two oldest were not breast fed. My youngest was. When my girls would get sick, colds flu other virus's. the oldest two would have a tough time of it. Most of the time had to take them to the Doc for anti biotics etc. But my youngest little girl would get a raging fever, and be well the next day. She was always a little healthier it seemed to me than my older girls. They're all fine now but I wonder if breast fed kids have stronger immune systems than kids who are fed formula. I think they do.
they do. The first "milk" that comes in is called colestrum. It's very important first food for all babies, not just human. I got the nit and gritty details from wiki below:
Newborns have very immature digestive systems, and colostrum delivers its nutrients in a very concentrated low-volume form. It has a mild laxative effect, encouraging the passing of the baby's first stool, which is called meconium. This clears excess bilirubin, a waste-product of dead red blood cells, which is produced in large quantities at birth due to blood volume reduction from the infant's body and helps prevent jaundice.
Colostrum is known to contain immune cells (as lymphocytes)[12] and many antibodies such as IgA, IgG, and IgM. These are some of the components of the adaptive immune system.
In preterm infants some IgA may be absorbed through the intestinal epithelium and enter the blood stream though there is very little uptake in full term babies.[13] This is due to the early "closure" of the intestinal epithelium to large molecule uptake in humans unlike the case in cattle which continue to uptake immunoglobulin from milk shortly after birth.
Other immune components of colostrum include the major components of the innate immune system, such as lactoferrin,[14] lysozyme,[15] lactoperoxidase,[16] complement,[17] and proline-rich polypeptides (PRP).[18] A number of cytokines (small messenger peptides that control the functioning of the immune system) are found in colostrum as well,[19] including interleukins,[19] tumor necrosis factor,[20] chemokines,[21] and others.
Colostrum also contains a number of growth factors, such as insulin-like growth factors I (IGF-1),[22] and II,[23] transforming growth factors alpha,[24] beta 1 and beta 2,[25][26] fibroblast growth factors,[27] epidermal growth factor,[28] granulocyte-macrophage-stimulating growth factor,[29] platelet-derived growth factor,[29] vascular endothelial growth factor,[30] and colony-stimulating factor-1.[31]
Colostrum is very rich in proteins, vitamin A, and sodium chloride, but contains lower amounts of carbohydrates, lipids, and potassium than mature milk. The most pertinent bioactive components in colostrum are growth factors and antimicrobial factors. The antibodies in colostrum provide passive immunity, while growth factors stimulate the development of the gut. They are passed to the neonate and provide the first protection against pathogens.