Sara Connolly, MD, FAAP, is a Board Certified Pediatrician who practices in Palm Beach County, Florida.
When your baby was first born, his or her immune system was like a book full of blank pages. Because your baby had never been exposed to bacteria or viruses, your baby had virtually no immunity. But the immune system is an amazing and complex system that begins to develop literally within hours of birth, as your baby’s body “learns” what pathogens are in his or her environment and how to fight them. Bundoo pediatrician, Dr. Sara Connolly, talks about how the immune system develops and how to help your baby avoid (and recover from) colds.
Bundoo: We’ve all heard about colostrum, that yellowish substance that a mom’s breasts begin to produce for the first few days of life and that bolsters baby’s immunity. How does colostrum work exactly? What is it doing to help boost immunity?
Dr. Sara Connolly: Colostrum is an amazing liquid in that it provides a significant amount of both nutrients and protective molecules in a very small volume. Colostrum contains proteins called immunoglobulins and leukocytes that work to protect the newborn from pathogens, such as viruses and bacteria. These immunoglobulins offer protection from illness at the mucosa, mouth, nose and digestive system. Think of the immunoglobulins as little soldiers lined up along the baby’s intestines, keeping out any harmful pathogens. Leukocytes identify, decrease, or destroy any harmful cells that are present. Studies show that the immune cells present in colostrum, and then in mature breast milk, adapt to the changing environment of the mother and baby. Because mothers and babies are (usually) in close proximity, the protective cells learn what the baby is exposed to and act accordingly. Colostrum also contains growth factor, thought to help in the maturation of the digestive system, which is a large part of the mature immune system.
Doctors talk about two types of immunity: innate and acquired. Can you give us a simple explanation of what these are and how they work in a young baby?
The innate immune system can be thought of as the first defense of the body. The skin, which is an excellent barrier to infection, is the best example of the innate immune system. Dirt, bacteria, and viruses sit atop the skin and are unable to get inside the body unless that skin is damaged. If the skin is broken, and bacteria enters the body, the rest of the innate immune system goes to work, surrounding the bacteria, killing it, and removing it. The acquired immune system is the advanced system. The cells involved here are exposed to a bacteria or virus, develop a response specifically to that threat and then combat it. If that threat returns in the future, the cells of the acquired immune system recognize it and are ready to fight once again. In essence, the acquired immune system has a memory! Scientists have taken advantage of the acquired immune system when creating vaccines. Vaccines are little particles taken from viruses or bacteria and injected into the body to stimulate the acquired immune system so that when the actual bacteria (or virus) enter the body, the body is ready to fight because it recognizes the particle as being familiar and dangerous.
Parents are often advised to avoid taking their babies out into public for the first few weeks of life. Why isn’t it a good idea to expose your baby to germs early on, so he or she can develop immunity more rapidly?
While we cannot keep our babies cocooned at home forever, keeping them at home initially offers some protection from common viruses and bacteria. Their immune systems are immature and not yet ready to mount a full attack against a pathogen. Viruses that may be easily tolerated by older infants and toddlers, such as RSV, can cause real trouble in newborns. Simple infections can become serious quickly in the first month of life, which is why doctors will take blood, urine, and even spinal fluid out of a newborn with a fever (100.4 or greater). Keeping them healthy decreases the amount of medical intervention they need.
Is there anything parents can do — with diet, supplements, or lifestyle — to help their baby’s immune system become stronger?
Give your newborn breast milk, if possible. Take advantage of colostrum, even if you decide to supplement with formula. Vaccinate all caregivers of newborns against the flu and whooping cough. Wash hands frequently, and make sure all people who hold and care for your newborn do the same. Keep your infant away from cigarette smoke because it can have a negative impact on the health of his or her lungs. Infants who are exclusively breastfed should take a vitamin D supplement daily.
Reviewed by Dr. Sara Connolly, August 2019