top of page

under the scope

Image Source Dr. Sarah Jensen

Mind-Blowing Components of Breastmilk

Breast milk perfectly meets the needs of your infant.  Scientists have done extensive research into the incredible composition of this liquid gold.  Here, we break down that research, so you can know exactly what your little is ingesting.  Breast milk is made up of several elements with a general composition of 87% water, 3.8% fat, 1.0% protein, and 7% carbohydrates (mostly in the form of lactose).  Together, the fat and lactose make up 90% of the total milk energy [1]. 




Variations in protein quantities adjust from 1.5g/100mL at birth down to 0.7g/100mL by the time they are six months old [2].  Breast milk contains both casein and whey proteins, with 50%-80% of that being the latter.  That is significant because whey only makes up 18% of cow’s milk protein.  Infant formulas also typically contain high levels of casein which can make it harder to digest than breast milk [3]. 



Fat content in breast milk is vital for neurological development, vitamin absorption, and calorie denseness.  Research has shown that the mean fat content is significantly higher during the day and evening compared to morning and night.  Breast milk also contains two essential fatty acids, which can be converted to AA, EPA, and DHA which are vital to growth, immune responses, cognitive development, and motor functions. 


Fat is not known to change with the infant’s age and intake is not related to feeding frequency [4].  However, fat content may vary depending on the maternal diet.  Regardless, breast milk always contains adequate nutrients for the child regardless of the mother’s nutritional deficiency.



Breast milk contains carbohydrates known as oligosaccharides.  Specially formulated, these protect the child from Salmonella, Listeria, and Campylobacter by binding the pathogens to keep them off the intestinal walls [5].  Oligosaccharides also help to promote a diverse microbiome and strengthen the immune system.  These carbohydrates are attached to lactose in the milk.  Lactose helps in mineral and calcium absorption. 



Research has shown that vitamin content in breast milk is directly connected to the mother’s dietary intake.  Continuation of prenatal vitamins can ensure mothers maintain proper nutrition to appropriately supplement their breast milk.  Unfortunately, breast milk does not contain high enough levels of vitamins D and K.  Due to this, pediatricians recommend a vitamin D supplement to protect infants from disorders such as rickets [3]. 



Minerals found in breast milk are vital to forming special enzymes and molecules.  Interestingly, mineral concentrations (such as iron, zinc, and copper) have been shown to be independent of mom's diet.  This is also known as active transport because these minerals are being actively moved to mammary tissue based on the infants needs rather than based on the mothers blood concentration [6].  


These living immune cells, also known as white blood cells, are only transferred to infants through breast milk.  Colostrum contains high levels of these cells before leveling out to a low baseline percentage.  The decrease in antibody concentration reflects the baby's reduced needs as their immune system matures.  Each time the infant or mother gets ill, that percentage radically increases in response to the infection [7]. 


Speaking of being ill, as leukocytes increase in breast milk, so does the presence of the appropriate antibody for the disorder.  A type of leukocyte, known as lymphocytes, travel to the mammary glands.  Lymphocytes secrete antigen-specific antibodies.  Breast milk is known to contain antibodies protective against many different enteric and respiratory pathogens [8].  Due to this direct nature, scientists believe that this not only provides infant protection, but also that studying human milk can aid in immunization strategies [9].  



Children who are breastfed have been shown to have lower risks for obesity later in life.  This may be due to hormones which are present in breast milk which could have downstream effects on appetite regulation [10]. 




Breast milk is perfectly created for your infant.  It is the exact cocktail of fats, proteins, carbohydrates, living cells, minerals, hormones, and SO MUCH MORE.  It is literally alive.  A part of your body that you can pass on to your child in order to keep them sustained, healthy, and happy.  


  1. Guo LH, Popov AP, Li HY, Wang YH, Bliznetsov V, Lo GQ, Balasubramanian N, Kwong DL. A small OCA on a 1/spl times/0.5-mm/sup 2/2.45-GHz RFID tag-design and integration based on a CMOS-compatible manufacturing technology. IEEE electron device letters. 2006 Feb;27(2):96-8.

  2. Jackson JG, Janszen DB, Lonnerdal B, Lien EL, Pramuk KP, Kuhlman CF. A multinational study of α-lactalbumin concentrations in human milk. The Journal of nutritional biochemistry. 2004 Sep 1;15(9):517-21.

  3. Martin CR, Ling PR, Blackburn GL. Review of infant feeding: key features of breast milk and infant formula. Nutrients. 2016 May 11;8(5):279.

  4. Domellöf, M., Lönnerdal, B., Dewey, K. G., Cohen, R. J., & Hernell, O. (2004). Iron, zinc, and copper concentrations in breast milk are independent of maternal mineral status. The American journal of clinical nutrition, 79(1), 111-115.

  5. Kent JC, Mitoulas LR, Cregan MD, Ramsay DT, Doherty DA, Hartmann PE. Volume and frequency of breastfeedings and fat content of breast milk throughout the day. Pediatrics. 2006 Mar 1;117(3):e387-95.

  6. Domellöf, M., Lönnerdal, B., Dewey, K. G., Cohen, R. J., & Hernell, O. (2004). Iron, zinc, and copper concentrations in breast milk are independent of maternal mineral status. The American journal of clinical nutrition, 79(1), 111-115.Gura T. Nature's first functional food.

  7. Pitt J. Breast milk leukocytes. Pediatrics. 1976 Nov 1;58(5):769-70.

  8. Andreas, N. J., Kampmann, B., & Le-Doare, K. M. (2015). Human breast milk: A review on its composition and bioactivity. Early human development, 91(11), 629-635.

  9. Noguera-Obenza, M., Ochoa, T. J., Gomez, H. F., Guerrero, M. L., Herrera-Insua, I., Morrow, A. L., ... & Cleary, T. G. (2003). Human milk secretory antibodies against attaching and effacing Escherichia coli antigens. Emerging infectious diseases, 9(5), 545.

  10. Savino F, Liguori SA. Update on breast milk hormones: leptin, ghrelin and adiponectin. Clinical Nutrition. 2008 Feb 1;27(1):42-7.

bottom of page