Breast Milk Composition and Benefits

Breast milk is the most optimal and healthy way to feed a baby (Read: Breastfeeding – For a healthy child and a healthy mother). Most mothers know this, but breastfeeding is not always easy. For some mothers, breastfeeding is easy and satisfying from the beginning. For others, it is difficult, painful, and unpleasant. It is good to think about breastfeeding before the baby is born. To better understand how important and irreplaceable mother’s milk is for the child, you have to familiarize yourself with its composition.


Colostrum – Composition and Benefits

Colostrum is a beneficial yellowish fluid produced in the first few days of lactation before mature milk. In the first days after giving birth, it provides the child with everything it needs. This is surprising because a newborn baby drinks only 50-100 ml of colostrum per day.

Compared to mature milk, colostrum has less lactose, fat, and vitamins soluble in water and more protein, fat-soluble vitamins, sodium, and zinc. 100 ml of colostrum has a calorific value of 48-64 kcal and is composed of 5.3g of lactose, 2.3g of protein, and 2.9g of fats. 

Colostrum is like the first natural baby vaccine. It has the highest concentration of immunoglobulins, leukocytes, and many other immune regulators essential for the immunity of the newborn baby.

The first food also contains prostaglandins – hormones that are not digested by the stomach of the newborn but settle on it and other organs to protect them. In this way, it prevents, among others, the colonization of pathological microorganisms on the surface of the intestinal mucosa.

Most importantly, colostrum also contains natural growth factors GH, IGF-1, GnRH, TGF-α, TGF-β, EGF, FGF, NgF, and PdgF, which support healthy development. Growth factors have a special impact on the normal development of most organs of the infant, including the intestines, blood vessels, nervous system, and hormonal glands.

Vitamins contained in colostrum: Vitamin A, thiamine (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), cobalamin (B12), pantothenic acid, folic acid, Vitamin C, cholecalciferol (D3), tocopherol (E ), and ubiquinone (Q10).

Mineral salts contained in colostrum: chlorine (Cl), chromium (Cr), zinc (Zn), phosphorus (P), aluminum (Al), cobalt (Co), magnesium (Mg), manganese (Mn), copper (Cu) , potassium (K), selenium (Se), sulfur (S), sodium (Na), calcium (Ca), and iron (Fe).

This unique food helps a child to adapt to the new environment right after leaving the mother’s womb. Even a small amount of colostrum is enough to nourish and protect the tiny body of a newborn.

The concentration of substances in the colostrum undergoes significant changes in the hours and days following birth, leading to its gradual transformation into milk. The transformation time depends on the mother’s body and varies from individual to individual. Sometimes it takes several hours, and sometimes, a few days. However, the richest colostrum is the secretion from the first lactation, i.e., in the first moments after its occurrence. Later, the substance slowly turns into the so-called transitional milk and then into ripe milk.


Transitional milk

This food appears between the fifth and fourteenth day of a child’s life. Women usually observe their bodies producing much more milk during this time than in the first phase (colostrum). Its composition changes gradually. Fat and basic carbohydrates or lactose levels go up while the amount of protein is reduced. The milk has a more watery consistency and greater transparency.


Ripe milk – Composition and benefits of mature milk

When the child is a month old, the milk will be fully ripe. From that moment, its composition will be permanent and will not change anymore.

Mature milk contains several ingredients to protect the child against bacterial and viral infections. This is not by chance. As a child grows older, he gets more exposed to external factors, e.g., when he begins to touch and put different objects in his mouth.

Ripe milk contains an average of 75 kcal/100 ml.


Mature milk mainly contains whey proteins that are easily digestible and do not reside in the stomach of the child. An important protein present is casein, which affects the absorption of copper, calcium, and zinc in the body. The mother’s milk contains up to 18 types of easily digestible amino acids.


Fats are an extremely important ingredient. They provide energy and form the building blocks for the brain and the nervous system. The fats in mother’s milk are easily digestible due to the presence of the lipase enzyme. Free fatty acids from breast milk have anti-inflammatory, antiviral, antifungal, and antibacterial benefits.

Sugars (lactose) 

They are used to build the brain tissue and absorb calcium as well as oligosaccharides or prebiotics, which stimulate the growth of normal bacterial flora in the child’s digestive tract.

The vitamins in breast milk include Vitamin A, which affects the development of skin, mucous membranes, and retina and Vitamin E, which protects against free radicals. The rest of the vitamins, which offer a wide spectrum of benefits for the infant are B1, B2, B6, B12, C, carotene/niacin, folic acid, pantothenic acid, and biotin.

The only vitamins that are lacking in sufficient amounts in breast milk are Vitamins D3 and K, which is why they are given to children as supplements.

Mineral salts contained in milk include sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), phosphorus (P), chlorine (Cl), iodine (I), zinc (Zn), copper (Cu) , cobalt (Co), manganese (Mn), fluorine (F), selenium (Se), aluminum (Al), chromium (Cr), and molybdenum (Mo).


As previously mentioned, mother’s milk contains several substances that support the development of the immune system. They include specific antibodies produced “regularly” by the mother’s body after contact with pathogenic microorganisms from the environment, blood elements, living cells, lactoferrin, nucleotides, interferon, and many others. In addition, mother’s milk also contains stem cells that can regenerate and transform into other types of cells. Their role is not yet fully known to scientists.

The presence of hormones in the milk, which control appetite and insulin processing in the child’s body, puts breastfed babies at less risk of obesity in later years.

And finally, the bonus. The food eaten by the nursing mother significantly affects the taste of breast milk, which is yet another advantage of choosing to breastfeed. The child will be able to learn new flavors, which cannot be said about formula milk.


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