The Composition of Breast Milk

My Baby Eats What?

Have you ever wondered what exactly is in breast milk? What is it composed of? Over the past few years of breastfeeding I have wondered what is actually in the milk they drink daily. Why is breast milk considered the best choice for my boys? What is it made of that makes it so special? Well, I have finally sat down and taken the time to understand the composition of breast milk a little more. What IS the stuff that comes flowing out of our now giant boobs after baby is born? Let me enlighten you!

Why Do You Breastfeed?

“So, why do you breastfeed?” Have you ever been asked this question? I cannot say that I personally have. If you have read my post A Love Like This, or Breastfeeding: My Experience, you would understand why I made this choice! However, researching the makeup (composition) of breast milk has only added to my list of reasons for breastfeeding my kids! So let’s get started.

Breast Milk Contains A Lot of AMAZING Things!

I have done my best to simplify my research and put the composition of breast milk into simpler terms for your basic understanding. Bear with me, as I am still learning, and certainly do not know ALL there is to know about the makeup of the liquid gold! As discussed in the National Library of Medicine’s article Human Milk Composition: Nutrients and Bioactive Factors, breast milk is composed of a lot of amazing things! You can follow the link to the NIH article if you are interested in all of the details.

• Macronutrients: These are the type of nutrients we need in larger quantities in order to have the energy we need to survive. Macronutrients include proteins, fats, lactose and energy. An interesting fact I learned is that if a baby is born premature, your breast milk will actually contain higher levels of protein than it would if your baby made it to term before delivery. How cool is that! This is just one way our breast milk is designed to be exactly what our specific baby needs at each point of his or her early life.
• Micronutrients: These are the vitamins and minerals our bodies need to function and stay healthy. Like most healthy foods do for us, breast milk contains most of the vitamins and minerals a newborn baby needs. According to the article by NIH, it can vary between mothers, but most breast milk contains vitamins A, B1, B2, B6, B12, D and iodine. Another interesting fact is, because some mothers’ diets postpartum are not what NIH describes as “optimal”, it is recommended mothers who breastfeed continue a multivitamin after delivery – hence the recommendation to continue the prenatal vitamin. Ever wonder why babies receive a vitamin K injection? A major reason is because breast milk is low in vitamin K! This helps prevent hemorrhagic disease in the baby.
• Bioactive components: to sum this up, breast milk contains elements that directly support the overall body function and health of the baby. These include growth factors which support the development of multiple body systems, and immune factors that protect baby against infection and disease. When babies are first born, they depend very much on their mother for immune protection. That is why women are highly encouraged to at least feed colostrum (more on this shortly) to their babies, even if they are planning to formula feed. The immune protecting factors in breast milk protect the development and strength of the immune system which is so important in their very early lives.

The above facts are definitely simplified for basic understanding, but still show some of the amazing qualities breast milk has. And these are not even all of the positive things that can be found in breast milk’s ingredient list! Another fun fact I have discovered in my time breast feeding, which is backed by the CDC, is that your baby’s saliva can change the constitution of breast milk to be what it needs at each developmental stage! As baby grows, their saliva helps it change to be exactly what their bodies need. That is probably one of the coolest facts I know yet. It was amazing to learn yet another way babies and mommies are perfectly designed for each other. We as mothers are our babies’ life line for the first several months to years of their lives.

The Stages of Breast Milk Development

Breast milk develops in stages. Some of these stages are visibly identifiable, and the others are less so. There are three stages described by NIH that are involved with the development of breast milk.

Stage One: Colostrum

In the first days and sometimes just before baby is born, a mother’s breast milk is produced in the form of colostrum, or the thick, yellow milk that babies drink right after being born. This stage of milk is only present for a few days to maybe a week or two, and has less volume than later stages. The reason for the small amount of colostrum that is produced is because baby’s stomach is so small just after birth. That being said, colostrum is rich in immune supportive components as well as growth and developmental factor. The primary functions of colostrum is to support immunity, provide nutrition and help the digestive system develop in the growing baby.

Stage Two: Transitional Milk

The next stage of breast milk development involves the transitional milk. This milk gradually replaces the colostrum that was so thick and rich in nutrients. Transitional milk has similar characteristics as colostrum, but focuses more on nutrition and developmental support, while colostrum focused on immune health also. Did you notice your boobs were suddenly huge and engorged a few days after delivery? It is hard to miss. When engorged, your breasts are usually warm, hard and tender. This is a sure sign that your transitional milk has come in!

Stage Three: Mature Milk

By about 4 to 6 weeks, your milk has fully matured and is comprised of most of the nutrients, factors and other bioactive components discussed in the previous section, that the baby needs to continue growing and developing. And don’t forget the baby’s saliva, which helps the milk continue to change as he or she grows. This milk continues to support developmental, immune and nutritional needs until baby is ready to be weaned and rely solely on food.

Breast Milk is Best

When you take into account all of the science, as well as the experiential evidence of mothers who breastfeed their babies, it is only obvious that breast milk is the best choice for your baby, at the very least immediately after birth. I cannot wait to learn more about why breastfeeding is so beneficial and so important, and I hope you will continue alongside me! To re-iterate what I have said before, I do not judge, nor do I condone or think negatively of any mother who chooses an alternative method of feeding their babies.

Every mother knows what is best for her child and herself, and these things are important to consider. I want to get into this more in a separate post, but I understand and know that there are several reasons why a mother might choose differently. These reasons might include psychological, physical and emotional. However, I also believe that many mothers give up on breastfeeding too early. I cannot wait to provide what I can as support for mothers who struggle with breastfeeding in the beginning.

If you would like a comprehensive and simplified summary of what I have discussed in this post, feel free to use the fact sheet included at the end!