Why is colostrum important?

Colostrum is the first fluid produced by the breast. It can start to be secreted as early as 16 weeks into the pregnancy and as late as 22 weeks. Colostrum meets the baby’s nutritional needs for the first few days of life. It contains many important components that promote health and protect the baby against illness. Colostrum has more protein and growth factors than mature milk and less lactose and fat. It promotes gut function and the growth of health-promoting bacteria in the bowel.

A) Describing colostrum

Colostrum can be secreted as early as 16 weeks into pregnancy and as late as 22 weeks. It is a unique liquid designed to meet all of the baby’s nutritional needs for the first few days after delivery, until the mother’s milk comes in, replacing the colostrum.
Colostrum has been called “liquid gold” because of its many health benefits, its usually straw (light yellow) colour, and the small amounts in which it is produced.

Some mothers have unncessary concerns about the adequacy or quality of colostrum and will supplement or replace it with other liquids. 

B) Colostrum components

Colostrum contains a variety of items including (Witkowska-Zimny 2017):

  • Antibodies
  • Lactoferrin
  • Fat-soluble vitamins: vitamin A1, vitamin D, vitamin E, and beta-carotene
  • Water-soluble vitamins: vitamin B1, vitamin B2, vitamin B3, various forms of vitamin B6, vitamin B12
  • Minerals: calcium, potassium, magnesium, sodium, zinc, iron, copper, and manganese
  • Whey proteins
  • Human milk oligosaccharides
  • Antibodies
  • White blood cells, skin cells, and stem cells
  • Growth factors: IGF-1, IGF-2, TGF-β, EGF, prolactin, and insulin
  • Essential and non-essential amino acids
  • Enzymes
  • Health-promoting bacteria
  • Potent signaling peptides (proline-rich peptides)

Colostrum also contains several fatty acids, particularly myristic acid, that attract babies (Gutiérrez-García 2017).

Colostrum is different from mature milk. It has:

  • Higher levels of:
    • Protein
    • Growth factors
    • Components that protect the baby from infection and inflammation
    • Antibodies
    • Lactoferrin
    • White blood cells
  • Lower levels of:

Colostrum is usually straw coloured but can be green occasionally. Rarely, it is bloody.

C) Functions of colostrum

Colostrum promotes gut function and the growth of healthy bacteria in the baby’s bowel (Jenness 1979). Compared with mature milk, it contains three times the level of human milk oligosaccharides, which support the growth of health-promoting bacteria (23 gm/L compared with 7 gm/L) (Smilowitz 2014).

Like mature breast milk, colostrum quickly responds with numerous bioactive compounds if the baby develops an infection (Breakey 2015). Research shows that colostrum protects babies against (Bardanzellu 2017):

  • Allergic and chronic diseases
  • High blood pressure
  • High cholesterol
  • Type 2 diabetes
  • Obesity

Colostrum contains several fatty acids, particularly myristic acid, that attract babies and may encourage their crawling to the breast after birth and calm them (Gutiérrez-García et al. 2017).

Colostrum has unique benefits for premature babies. 

D) The amount of colostrum

Colostrum is produced in small amounts. To compensate, human babies are born with relatively higher levels of fat (about 10%) which can be used for energy until the milk comes in (McClellan 2008).


Bardanzellu F, Fanos V, Reali A. "Omics" in Human Colostrum and Mature Milk: Looking to Old Data with New Eyes. Nutrients. 2017 Aug 7;9(8). pii: E843
Breakey AA, Hinde K, Valeggia CR, et al. Illness in breastfeeding infants relates to concentration of lactoferrin and secretory Immunoglobulin A in mother’s milk. Evolution, Medicine, and Public Health. 2015(1):21-31
Gutiérrez-García AG, Contreras CM, Díaz-Marte C. Myristic acid in amniotic fluid produces appetitive responses in human newborns. Early Hum Dev. 2017 Sep 5;115:32-37

Jenness R. The composition of human milk. Semin Perinatol. 1979 Jul;3(3):225-39
McClellan HL, Miller JS, Hartman PE. Evolution of lactation: Nutrition v. Protection with special reference to five mammalian species. Nutrition Research Reviews. 2008;21(2): 97–116
Smilowitz JT, Lebrilla CB, Mills DA, et al. Breast milk oligosaccharides: structure-function relationships in the neonate. Annual review of nutrition. 2014;34:143-169
Witkowska-Zimny M, Kaminska-El-Hassan E. Cells of human breast milk. Cell Mol Biol Lett. 2017;22:11