Breastfeeding And Breast Milk

This article is not meant to scrutinise or diminish the hard work of mothers that don’t choose to or can’t breastfeed their babies. It’s not an easy task being a parent, especially to a first child, which is something I’m currently going through myself as a first-time father. Parents should have the right to decide what’s best for their child and we have to understand that many mothers are not in a position to be able to provide their own milk. This article is meant to provide everyone (not just parents) with information about this absolutely astounding compound that a human body is able to produce.

Nutrition in the first year of life is crucial to an infant's development and lifelong health. Deficiencies are intrinsically linked to impaired mental and physical growth, risk of developing metabolic and cardiovascular diseases such as obesity, diabetes, and hypertension later in life. Human breast milk provides all the nutrients, vitamins, minerals, and even prebiotics and immune cells to enable the baby not only to survive but to grow and thrive. The ageing process is never as potent as it is in the first years of life. By observing babies we can learn a lot about the mechanisms that cause ageing and what to do to slow down its effects when we are older.

Breastfeeding Stages

The delivery of the placenta triggers a rapid drop in progesterone and elevated levels of hormones cortisol and prolactin. The breasts swell, and copious milk production begins. Maintaining lactation requires both mechanical and hormonal inputs. Nipple stimulation and subsequent milk removal promote the continued release of prolactin and oxytocin. In turn, these hormones drive the ongoing production and release of milk (respectively).

The first liquid that a mother produces is a thick sticky fluid called colostrum. Its function is more immunological than nutritional. Next is transitional milk which comes in the first few weeks after childbirth and is high in lactose. Four to six weeks after childbirth, a mother’s milk is considered mature.

During an early part of a single feeding session, the milk has a more watery consistency and is high in lactose (called foremilk) and during the later part of the feeding session, it is more creamy and high in fats (called high milk). The milk is incredibly dynamic, it changes during the feeding session, throughout the day and the lactation period in response to the baby’s needs. Incredibly, it is influenced by circadian rhythms as well, to help the infant establish their own sleep/wake cycles. The nighttime feeds contain more melatonin and amino acids like tryptophan to help the baby sleep. Certain nucleotides peek during the day and others during the night to help this process further. For this reason, if the infant is fed with previously expressed breast milk, they should be provided with the milk expressed at the same time of the day they are being fed.

The composition of breast milk

As mentioned, human breast milk contains all the proteins, fats, carbohydrates, minerals and vitamins needed to grow a human life.

Although there have been approximately 415 proteins identified, the total protein content in human breast milk is lower than milk from other species, which corresponds to the slower growth rate of human infants compared to let’s say a calf. Along with nutrition, proteins also provide antimicrobial and immunological factors.

Fats represent around half of breast milk’s total calories. In addition to providing babies with the necessary energy for growth, fats aid in the maturation of the infant's gastrointestinal and central nervous systems and provide protection from pathogens, including group-B Streptococcus bacteria. Most infant formulas do not contain the same properties of fat molecules, what’s worse most of them are laden with highly inflammatory vegetable oils.

The types of fatty acids in the milk are highly reliant on the mother’s diet, especially when it comes to the all-important omega 3 fatty acid which plays a key role in the baby’s mental and psychomotor development. DHA is the most abundant omega 3 fatty acid in the newborn's brain. The study has shown that the infants of lactating mothers who took 400mg of DHA supplement had 123% more DHA in breast milk compared to a placebo group and lower omega 3 to omega 6 ratios which is crucial in reducing many chronic diseases and inflammation. Their babies also had larger volumes of brain regions that relate to consciousness, communication, memory, attention and integration of motor, sensory and cognitive performance.

The main carbohydrate is lactose (it provides the necessary energy for the infant's brain) followed by a non-nutritional compound called human milk oligosaccharides (HMOs) which average at around 20g per litre of milk. HMOs are prebiotics that serve as food for the child’s developing gut microbiome. More than 200 HMOs have been identified, their quantity and composition are genetically determined and differ slightly between women. Not only do they enable the baby’s friendly gut bacteria to thrive, but they also prevent the colonisation of pathogenic bacteria in the newly formed and still vulnerable infant’s gut.

HMO’s also protect the gut from the infection-causing bacteria by serving as a decoy. When the bad bacteria enter the gut, the HMOs mimic the shape of specific carbohydrates that line the gut. This way they lure the bad bacteria to bind to them instead. Moreover, they increase the membrane permeability of the pathogenic bacteria making them more vulnerable to antimicrobials and antibiotics. HMOs are very specific to human milk and have not yet been replicated in formulas.

Newborns and infants are regularly exposed to antibiotics and other medication that disturbs the healthy gut biodiversity. Likewise, babies born by C-section lack exposure to vaginal bacteria which would enable them to form a strong base for the developing immune system. So repopulating babies’ microbiome with healthy bacteria is extremely important. Many of the microbes we develop by the age of five will be with us for the rest of our lives, so we really want to start that relationship in the best possible way. Breast milk is not a sterile solution, it’s actually packed with hundreds of types of bacteria. They arrive there through mothers skin, infant’s saliva and other means. Exposure to this rich bacterial community by breastfeeding may contribute to the differences observed in the gut microbial population between breastfed and formula-fed infants.

Breast milk also contains vitamins and minerals which are heavily dependent on the mother’s diet and tissue stores. If they are depleted, supplementation might be necessary. However, vitamin K1 which is important for blood clotting is low in breast milk regardless of the diet and it’s often recommended for babies to receive an injection shortly after birth to prevent hemorrhaging. Iron is another element that is low in breast milk and plays a key role in infants growth. It might seem counterintuitive, but microbes require iron for their growth too, so this is nature’s way of preventing infection especially immediately after birth. To prevent the development of anemia, the introduction of iron-rich foods after 6 months of age is recommended. Breast milk also contains low levels of vitamin D, but studies have shown that mothers who take a daily dose of vitamin D of 6,000 IU provide their babies with enough of this vitamin to prevent deficiency.

Drugs and breast milk

Infants are not as good at metabolising drugs in the early stages of life, especially in the first two months of age. Drugs to absolutely avoid during breastfeeding are anti-cancer drugs, lithium, oral retinoids, high dose iodine, amiodarone, and gold salts. But even social drugs like alcohol, caffeine, and cannabis can carry risks to the infant.

Keep in mind that anything a mother eats, drinks, supplements or smokes can end up in her breast milk. For example, heavy metals like cadmium which is a carcinogen and can impair the metabolism of nutrients like selenium, zinc, copper, and magnesium. Smoking cigarettes not only introduces toxic chemicals to breast milk but also inhibits the absorption of many nutrients and should be absolutely avoided in this period. Passive smoking is also dangerous to babies’ health, so avoid handling babies in the same clothes you smoked in or putting them in a closed environment in which smoking was present. Women that were exposed to second-hand smoke were 30% more likely to stop breastfeeding early compared to women in non-smoking households. Nicotine has a host of harmful effects on infants who excrete it four times slower than adults. Shorter sleep, respiratory infections, colic, and increased risk of SIDS (sudden infant death syndrome) are just a few to mention. Smoking marihuana while breastfeeding in the first month of an infant's life is shown to result in decreased infant’s motor development.

Alcohol passes through breast milk but due to the infant’s high body water content, the amount they are exposed to is low. However, infants detoxify alcohol less efficiently than adults do and can cause negative effects like impaired motor development. Alcohol is broken down at a constant rate so exercise or water drinking won’t speed up the process.

Caffeine is low in breast milk, approximately 1% of that in maternal blood concentration and usually peaks 1-2 hours after ingestion. Caffeine metabolism in infants is very poor. Infants from mothers who consumed high amounts of caffeine (750mg per day or more - approx 6-7 cups of coffee) could achieve toxic levels of caffeine from breast milk.

Caution is advised when using all these commonly used social drugs.

Other benefits of breastfeeding

Incredibly, breast milk also contains immune cells that correspond with the baby's needs via constant communication with the mother’s body that happens while breastfeeding. The immune system is the last one to get fully developed and it can take years to match the one of adults. Breast milk is full of compounds that work together to provide a compensatory immune system: antimicrobial and anti-inflammatory agents, T-cells, and leukocytes among many others. The concentration of leukocytes (living white blood cells that represent an active immune system) are highest in colostrum and they slowly drop as the milk matures reaching a baseline level. But if the infant, mother or both get an infection the number of leukocytes can increase up to 94% above baseline! Children who are breastfed for any length of time are 64% less likely to develop gut infections and the effects last up to two months after the cessation of breastfeeding! Additionally, case-controlled studies show that infants who were exclusively breastfed for more than four months are 72% less likely to be hospitalised due to lower respiratory infection in the first year of life compared to formula-fed infants. Other studies show great reductions in eczema, celiac disease, and childhood cancers.

Breast milk is incredibly dynamic and its composition is constantly changing: when the baby is dehydrated it becomes more watery when it needs to gain weight it becomes more caloric dense when an immune response is needed it’s adjusted again.

If that’s still not enough, breast milk contains stem cells too! Stem cells are the body's raw materials - cells from which all other cells with specialized functions are generated. These specific stem cells from the mother are called mammary stem cells. Some preclinical trials suggest they may help establish organs like the liver, kidneys, pancreas and brain. This phenomenon where mother’s cells are found in the offspring and remain there long term suggests that they were transmitted via breast milk and can help boost infant's development early in life.

A large clinical trial of more than 13,000 children from 13 hospitals found that total and exclusive breastfeeding led to increased performance in intelligence tests at the age of six. Breastfed children averaged around 7.5 points higher than formula-fed ones. Another study showed 20-30% more white matter in exclusively breastfed two-year-olds, especially in regions related to cognition, emotion regulation and language.

Breastfeeding is especially important for premature babies. A large study of 900 babies showed that exclusive breastfeeding reduced cardiovascular complications associated with pre-term birth that result later in life as hypertension and poor metabolic function. Another study also showed they had lower blood pressure at the age of 13-16 years.

Breastfeeding has benefits for mothers too. A reduction in breast and ovarian cancer has been observed and quicker return to normal weight after birth.

WHO recommends exclusive breastfeeding for the first six months of an infant's life and then continued breastfeeding while introducing age-appropriate foods until an infant is 2 years old or beyond if desired. In Australian Federal Law breastfeeding is a right, not a privilege, so never hesitate to feed your baby in public if you feel the need to do so. It is illegal to discriminate against breastfeeding. This includes expressing milk by hand or a breast pump to feed the baby later.

Breastfeeding can present many challenges in the first weeks for new mothers so help from a lactation consultant might be considered. If there isn’t sufficient milk or there are other health concerns, donor breast milk might be a viable alternative. Having said all that, this article is not meant to criticise the decisions of mothers who decide not to breastfeed. The main goal is to educate and spark conversations.

The article was modified from the dr. Rhonda Patrick podcast #056 and other sources.