Nutritional Composition of Breast Milk

Nutritional Composition of Breast Milk

breastfeeding milkThanks to scientists and baby-formula manufacturers, the nutritional composition of breast milk has been de-mystified. So what exactly is in breast milk to make it the “perfect food” for babies?<

1. Fats in Nutritional Composition of Breast Milk

The nutritional composition of breast milk begins with fat. If you take all the water out of breast milk, half of what’s left behind is fat. And, there’s lots of cholesterol too. Don’t worry: babies, infants, and young children need fats because it is needed for the development of the nervous system. Specifically, fats are need to cover & protective nerve cells. They are also integral parts of cell membranes.Researchers have found that breastfed babies grow up to be adults with lower cholesterol. It is suggested that exposing babies to cholesterol in the breast milk allows their bodies to learn how to regulate cholesterol so that as adults, they have lower cholesterol levels.

In breast milk, there is an enzyme called lipase. Lipase breaks down fat so that the fat is in small globules. This allows for better digestion and absorption in Baby’s stomach.

In contrast, the fat globules in baby-formula are large because they are from cow’s milk (cow’s milk is used to make most formulas). The fat from cow’s milk is not absorbed as well by human babies. Formula manufacturers have tried to correct this by replacing cow’s milk fat with plant oils (corn, coconut, olive, peanut, and others).

nutritional composition of breast milk
The nutritional composition of breast milk includes fats and cholesterol. These components are necessary for developing babies. Research published in the journal of Pediatrics show that the high levels of cholesterol in breast milk may lead to lower levels of cholesterol in adults. Photo from

2. Carbohydrates in Nutritional Composition of Breast Milk

The next big component of breast milk is carbohydrates (37%). Most people know carbohydrates as the macromolecule found in bread, pasta and rice. But in breast milk, most of the carbohydrates are in the form of lactose. Lactose is a disaccharide: it is made up of two sugars (galactose and glucose) linked together. Lactose provides Baby with energy so that he can do the things that babies do: breath, eat, cry, wriggle, poop, learn, grow, and develop. Lactose is converted to lactic acid by the Lactobacillus (a naturally occurring gut bacterium). The lactic acid makes Baby’s stomach acidic. This in turn prevents the growth of harmful bacteria that are not supposed to be in Baby’s stomach. Cow’s milk (used to make baby formula) has less than 10% lactose. Formulas manufacturers try to match the nutritional composition of breast milk by adding more lactose.

lactose in breast milk
Lactose is a disaccharide composed of one glucose and one galactose unit. Lactose is the predominant carbohydrate in breast milk. Photo from

3. Proteins in Nutritional Composition of Breast Milk

There are high levels of protein in colostrum and the levels gradually decrease as Baby grows older and older. By six months of age, Baby should get an external source of protein, for example in baby cereals or other solid foods.

Mature milk has many different kinds of proteins but the two major players are whey and casein. Whey is a smooth, liquidly-type of protein whereas casein is a coarse protein that tends to curdle. In breast milk, 60% to 80% of the proteins are of the whey type. Whey is easier to digest and it is absorbed well in Baby’s stomach. Because of this, babies fed on breast milk will have runny poops, and be hungry more often. Cow’s milk has more casein and less whey. Casein is harder to digest & absorb because it clumps in Baby’s stomach. Formula-fed babies are hungry less often because the formula isn’t being digested. As well, when the Babies poop, the poops are more solid. Formula manufacturers try to correct for this by adding emulsifiers to help break apart the casein. Other than whey and casein, there are many other important proteins:

  • antibodies (helps fight against bacterial and viral infections),
  • lactoferrin (binds to iron and helps Baby absorb iron. It also prevents the growth of harmful microorganisms that use iron),
  • bifidus factor (encourages the growth of lactobacillus which helps prevents the growth of other harmful stomach bacteria),
  • lipase, amylase, lysozyme, and other enzymes (helps in digestion and creates a healthy environment in Baby’s intestines).

proteins antibodies in breast milk
An antibody is a kind of protein. It is often shown as a Y-shaped molecule. Antibodies work by binding to and incapacitating foreign particles such as bacteria. Photo from

4. Vitamins, Minerals, & More in Nutritional Composition of Breast Milk

Breast milk contains vitamins and minerals which, for the most part, can be simulated in formulas. However, the nutritional composition of breast milk includes over 100 different components most of which we still do not know how they affect Baby’s growth and development. Currently, formula manufactures have not been able to recreate, exactly, the nutritional composition of breast milk. Click here to see the nutritional composition of breast milk.

vitamins in breast milk

Breast milk is considered to have the perfect combination of nutrients. Formula manufacturers use the contents of breast milk as the standard in which to compare with.