What Are The “Ingredients” in Human Milk?

I recently saw on a blog here the food label for infant formula, and a “guess what this is”. People were pretty shocked at the ingredients on the label. Have you ever wondered exactly what is in human milk?

As a Certified Lactation Educator/Counselor, I feel it is important to get the word on what human milk is made up of…because this is some pretty amazing stuff that our body can produce! Human milk is constantly changing in composition from feeding to feeding. As the baby gets older, the composition of human milk changes as well. Human milk contains more than 200 known components, and some that have yet to be discovered! Human milk is a living substance, full of some amazing properties. The benefits of human milk for both baby and mama are well known.

Recently I perused through some my education tools/links to put together a resource describing some of the many amazing nutrients in human milk. There is no way I can include everything, so I am focusing on just a few components. I think you will find that human milk is pretty incredible stuff!

There is nothing more primal than breastfeeding!


Here is a link to a chart that breaks down many of the components of human milk. I found this chart be a very helpful educational tool.

For the first approximately zero to seven days colostrum is a thicker form of human milk that helps the baby learn to suck and swallow. There may be only ½-1 tsp produced at first, but babies tummy is approximately the size of a marble on that first day! Colostrum is high in carbohydrates, protein, and antibodies and low in fat. It is often referred to as “babies first immunizations” Colostrum is very easy to digest, and very high in nutrients. It helps baby pass their first stool, and helps prevent jaundice. Colostrum is yellow in color because of it’s high levels of beta carotene. Colostrum helps to coat and seal the infant gut to protect it from harmful pathogens. It “seals” the loose junctions in the newborn gut. According to “Counseling the Nursing Mother, 5th edition”, Judith Lauwers, BA, IBCLC, FILCA and Anna Seisher, MBA, IBCLA (pages 188-189) Colostrum is composed of approximately 70% leukocytes. Leukocytes defend the body against infectious diseases and foreign materials. The mother produces antibodies to all the diseases which she has already acquired. Colostrum contains many antibodies produced by her body. She passes these antibodies through her colostrum and her milk.

After approximately day 3-7 mature milk starts to come in. Here are some of the awesome components in mature human milk:

The first ingredient in human milk is water. Babies need no other form of hydration. At the beginning of the feeding the milk is more diluted. This quenches the babies thirst. As the feeding goes on, the milk becomes more concentrated and nutrient rich. Many people refer to it has “foremilk” and “hindmilk”, so there is a misconception that there are two different kinds of milk. It’s all the same milk, and there are not two separate compartments. It just gets more concentrated toward the end of the feeding.

Human milk is very sweet. As one of my nurslings once said “It tastes like strawberries!” The infant brain grows very fast that first year and requires a ton of energy. The carbohydrates are lactose and these amazing things called Oligosaccharides-these are complex sugar molecules specifically designed for human consumption. They actually have a protective mechanism against infections. This study demonstrated “HMO (human milk oligosaccharides) reach the colon intact where their prebiotic effects promote healthy gut colonization. HMO can also function as soluble decoy receptors and block adhesion of microbial pathogens to epithelial surfaces.”

There are several different proteins in human milk. However, proteins comprise only about .8% of human milk. Human milk contains human specific casein and whey. Human milk whey contains lactoferrin-which has a protective mechanism against GI infections.

One pretty amazing protein/fatty acid in human milk is known as HAMLET (Human Alpha-lactalbumin Made LEthal to Tumour cells). What is amazing about HAMLET is that it kills cancer cells but not healthy cells! “ According this THIS Science Daily article: HAMLET was discovered by chance when researchers were studying the antibacterial properties of breast milk. Further studies showed that HAMLET comprises a protein and a fatty acid that are both found naturally in breast milk. So far, however, it has not been proven that the HAMLET complex is spontaneously formed in the milk. It is speculated, however, that HAMLET can form in the acidic environment of the babies´ stomachs. Laboratory experiments have shown that HAMLET kills 40 different types of cancer, and the researchers are now going on to study its effect on skin cancer, tumours in the mucous membranes and brain tumours. Importantly, HAMLET kills only cancer cells and does not affect healthy cells.”

There are also several non protein amino-acids, peptides, nucleotides. Here are a few of the 20 essential amino acids:
“Taurine is the second most common amino acid found in breast milk. It is nonexistent in cow’s milk. It functions as a neurotransmitter or a neuromodulator in the brain and retina. In addition, it supports conjugation of bile acids. Many companies are adding this amino acid to formula now.
Nucleotides are significant in protein synthesis and they promote growth and differentiation of organs and tissues. They also improve the metabolism of lipids. There are 10 times more nucleotides in breast milk than in cow’s milk. Carnitine is vital for catabolism of long chain fatty acids.”

There are several different kinds of fatty acids in human milk. According to “Counseling the Nursing Mother, 5th edition”, Judith Lauwers, BA, IBCLC, FILCA and Anna Seisher, MBA, IBCLA (pg 190), Fat in human milk provides 50% of the infants energy needs. There are more than 200 fatty acids found in human milk. There are both saturated and unsaturated fatty acids (primarily medium and long chained in form), as well as DHA from linoleic acid, which is essential for the development of visual acuity.
Medium Chain Fatty acids are among the unique components of human milk. According to the Coconut Research Center, medium chain fatty acids are in human milk because they are easy for an infant’s immature digestive system to absorb and utilize. They help give the baby the nutrients and energy it needs to grow and develop properly. Because they also have antimicrobial properties they give the infant some degree of protection against viruses such as HIV and herpes, bacteria such a chlamydia and H. pylorus, fungi such as Candida and protozoa such as giardia.

Vitamins and Minerals:
According to “Counseling the Nursing Mother, 5th edition”, Judith Lauwers, BA, IBCLC, FILCA and Anna Seisher, MBA, IBCLA (page 192), generally all vitamins are available in sufficient quantities in human milk. One major concern people have is about adequate vitamin D levels, and whether or not it needs to be supplemented. Kellymom.com (my FAVORITE go to evidence-based breastfeeding resource) has a great vitamin D resource page here. Kellymom.com also has a great resource page here for parents on vitamin supplementation for mom and baby-when and if it is necessary.

Growth Factors and Hormones:
Hormones in human milk help with satiety, comfort, growth, appetite regulation, and digestion. There are growth hormones, such as epidermal growth factor, that aids with growth and healing of the infant gut. Oxytocin is a “relaxing” hormone released during milk let-down. This hormone relaxes both mom and baby during nursing. According to this publication “Data accumulated over recent years have significantly advanced our understanding of growth factors, cytokines, and hormones in breast milk. Here we deal with leptin, adiponectin, IGF-I, ghrelin, and the more recently discovered hormones, obestatin, and resistin, which are present in breast milk and involved in food intake regulation and energy balance.” There are digestive hormones that are triggered when baby sucks-these digestive hormones may help the baby feel satiety.

Live Enzymes and Probiotics:
My favorite part of human milk is that it is a living substance loaded with protective prebiotics, probiotics, and enzymes! I always felt like a superhero providing these unique nutrients. There are several antibacterial, antiviral, anti parasitic factors found in human milk (such as Secretory IgA and IgG) that actually kill off harmful bacteria such as e-coli, viruses, the flu as well as many other toxins and bad bacterias. According to “Counseling the Nursing Mother, 5th edition”, Judith Lauwers, BA, IBCLC, FILCA and Anna Seisher, MBA, IBCLA (page 196) Immunoglobulins present in both colostrum and mature milk protect the infant’s GI tract against penetration by organisms and antigens. Immunoglobulin A (aka IgA) has a very high anti-viral factor. “It binds to bacteria and prevents pathogens from binding to receptor sites and invading the gut.” Lymphocytes and macrophages digest bacteria and make IgA and other protective substances.

Human milk protects the infant against a host of disease and confers lifelong immunities!

There is so much more to human milk (and probably several important components that I left out). Human milk is very complex and different in composition from mother to mother. The nutrition content changes as the baby gets older. Toddler human milk is less copious (as toddlers eat more solids) yet more nutrient dense and high in fat.

My hope is that this leaves you with a greater appreciation for and understanding of the components that make up human milk!


* Please note: This is a personal blog. I am not a Doctor or a Dietician. All data and information provided on this site is for informational/educational purposes only. It is not intended to be a substitution for professional medical advice.




  1. Laura Midura says:

    Another great post! I enjoyed reading this (while Sophie snuggled in for a nurse and nap). :)

  2. Thank you so much Kathy! Tons of info, thanks for generously sharing!

  3. Wow this is so interesting! Haven’t thought too much about human milk since I gave birth to my daughter a few years ago 😉 Thanks for sharing your knowledge about this topic with us.

  4. Wow we make some great stuff huh? So cool to see the components that make up our milk.

  5. It’s funny– I’ve never really stopped to think about the ingredients in breast milk…or the fact that it even HAS ingredients…because we make it without thinking about it (sorry if that sounds weird 😉 ) Thanks so much for sharing this– I’m not a mother yet, but this info will definitely be useful someday!

  6. Aliza Chana Zaleon says:

    This is so interesting! I’m not a mother yet, but hope to be one day, and this is so informative, making me feel even more confident that breast feeding is the best choice whenever possible! I struggle with chronic illness, and that worries me that it may interfere with my future breast feeding ability. I’m hoping not!


  1. […] You can find many answers to all your breastfeeding questions and concerns on this website. Here is a blog post I wrote about the amazing ingredients in human milk. If breastfeeding does not work […]

  2. […] You can find many answers to all your breastfeeding questions and concerns on this website. Here is a blog post I wrote about the amazing ingredients in human milk. If breastfeeding does not work […]

  3. […] You can find many answers to all your breastfeeding questions and concerns on this website. Here is a blog post I wrote about the amazing ingredients in human milk. If breastfeeding does not work […]

  4. […] all marketing. Literally. I remember when I would not start weaning my 1 year old from my milk (read here the ingredients in human milk) to pasteurized cow’s milk I had a well-meaning friend warn me several times that he may be […]

Speak Your Mind