Where do we begin. There are so many reasons to breastfeed. It is harder to think of reasons not to breastfeed than to list all the ways it is best for you and your baby.
Nutritionally: Everyone knows breast milk is the best choice for your baby’s needs. It has just the right amount of digestible proteins, carbohydrates, fat, vitamins, and minerals. This perfect food also helps to colonize your baby’s
gut with the right bacteria (microbiome) to support a healthy digestive system, something that continues as they
begin to eat regular foods. It contains living cells from your body that are transferred to your baby, cells that help support your baby’s immune system.
Efficiency: Breastfeeding is free and always accessible. It is portable and dispensed at the perfect temperature. You don’t need gadgets, bottles, or an electric outlet to breastfeed your baby. You can do it anytime, anywhere and your body will continue to make it no matter what you eat.
Emotionally: Many cultures consider the first month after a baby is born as the “fourth trimester” of pregnancy. Breastfeeding is an important part of this transition time because it physiologically helps to heal your body and bond with your baby. When your baby nurses on your breast, your brain secretes bioactive hormones to contract your uterus to its prepregnancy size, establish your milk supply, release milk from your breasts, and calm your emotions. One of these hormones, oxytocin, is also called the love hormone because it is the same hormone our brains secrete when we fall in love.
What is in Breastmilk?
Kcalories – 60-75 kcal/100 ml
Water – 90g/100ml water
Protein – 0.8-1.3 g/100 ml, 30% casein and 70% whey
Whey proteins include alpha lactalbumin, lactoferrin, lysozyme, serum albumin, secretory immunoglobulin IgA (sIgA), insulin, epidermal growth factor (EGF), and many enzymes. These proteins serve many functions, such as host defense, nutrition, and enzymatic activity. Specifically oligosaccharides protect the gut from bacterial attachment; immunoglobulins, primarily sIgA, protect the gut lining from infection; and whey proteins kill bacteria, viruses, and fungi.
Casein has low solubility and can turn into clots or curds. Whey proteins are soluble and remain in liquid form, making them more easily digestible. Human breast milk is lower in casein than most animal milks, such as cow’s milk, which has 18% whey and 82% casein. Excessive casein can overwhelm the infant’s maturing kidneys. Lactoferrin, sIgA, lysozyme, and alpha lactalbumin are found only in human milk. Human milk does not contain beta-lactoglobulin, found in cow’s milk, which infants cannot digest. For all these reasons, a cow’s milk-based formula is a common cause of infant intolerance.
Carbohydrate – 6.9 to 7.4 g/100 ml, 90 to 95% lactose.
After colostrum transitions to mature milk, the lactose concentration remains constant. It is mainly used as an energy source, but a small amount is not absorbed and promotes softer stools. It also contains 1g/100ml of 100 or more oligosaccharides. These are carbohydrate polymers that control intestinal flora by promoting certain bacterial strains to grow in the gut, therefore protecting against infection.
Fat – 3 to 5 g/100 ml, mostly in the form of palmitic and oleic acids.
Fats provide 50% of the calories in human milk and therefore are a major source of energy. The fat content of milk is variable throughout the day and increases over the course of breastfeeding. It is present mostly in the alveolar sacs and distal ducts, so the infant must first drain the “foremilk” to get to this fat rich “hindmilk.” Lipids are present in fat globules, lipase, and many essential fatty acids in the form of triglycerides. Certain fatty acids are of interest—DHA (docosahexaeonic acid) and ARA (arachnidonic acid)—because they are found only in human milk. They are important in neurological and visual development of the infant.
Vitamins and Minerals – 0.2g/100ml in total, including:
- 25mg/100ml calcium,
- 9mg/100ml phosphorus
- 200mg/100ml sodium
- 3.5mg/100ml magnesium
- 5mg/100ml vitamin C
- smaller amounts of iron, copper, zinc, vitamin A, pantothenic acid, nicotinic acid, iodine
- Trace amounts of vitamins K, D, E, and B
Zinc, Iron, Vitamin D
There is a high concentration of zinc initially, but it declines over the first 6 months of nursing. Also, there is a low concentration of iron. Infants are born with sufficient iron stores at birth, but they decline over the first 6 months of life. Similarly, vitamin D is present in low concentrations in human milk and is not easily supplemented to the mother. Current recommendations from the American Academy of Pediatrics include vitamin D supplementation for infants who are exclusively breastfed for the first 6 months of life. Solid foods are introduced at 6 months, resolving the need for iron and zinc.
Breast milk contains maternal cells (such as leukocytes) and epithelial cells, such as stem cells, lactocytes, myoepithelial cells, and progenitor cells. Neutrophils are present in greater concentrations in colostrum. They decrease in mature milk and are replaced by macrophages and lymphocytes.