Breastmilk is a Miracle of Evolution
November 29th, 2021
After the birth of a child, a beautiful event occurs and provides a point of visceral connection physically and epigenetically between mom and her babe. That event is breastfeeding. Mother’s milk is an evolutionary marvel whereby a mother dedicates part of her energy stores to her offspring for survival. She gives of herself literally and figuratively even during periods of food scarcity. Over thousands of years, humans have evolved this dynamic and rich fluid to promote species
survival in the context of our dependent selves as babies. We have massive brains needing large amounts of energy to grow and mother’s milk is the culmination of the species learned process of survival. Human milk is the perfect dynamic personalized food for an infant to thrive. It is different for each mother child dyad. It changes based on environmental and human flux. It is in simple terms the best food for a newborn while simultaneously being the best medicine for all that ails a newborn.
What is breastmilk?
It is the amazing human derived source of infant nutrition for the first many months of a child's life. Let's start by looking at infant and childhood disease reduction as a result of exclusive breastfeeding:
1) Reduces the risk of illness from most forms of bacterial and viral disease in infancy
2) Reduced rates of sudden infant death syndrome by 30%
3) 50% reduction in necrotizing enterocolitis, a life-threatening intestinal disease of preterm infants
4) Reduces hospital readmission rates for preterm infants during their first year of life
5) Better neurodevelopmental outcomes
6) Infant mortality rates are reduced by 21%
7) Provides protection against the development of allergies, especially with a strong family history of allergic disease
8) Reductions in inflammatory bowel disease and celiac disease
9) Reductions in autoimmune diabetes and some forms of cancer
10) Reduced metabolic disease and excess weight gain
And much more....
If there were a drug that would do all of this, would there be a parent on earth that wouldn't give it to their child? I think not Yet, we see parents every day in clinic and the hospital choosing to use cow milk based formula instead. Is it a lack of knowledge, convenience, difficulty with breastfeeding, socioeconomic pressure based or some other reason? The answer is that it does not matter why the choice is made. We are not going to judge it so much as continue to do our job to counsel regarding the scientific truths of nursing human milk as opposed to formula.
An infant is gaining metabolic programming from mom via the breastmilk. This is to say that the child learns epigenetically and nutritionally from mother's milk what the outside world is going to look like. Is it feast or famine? Is it cold or warm? This is happening real time as mom consumes a certain local diet and experiences her world and has her world view. These signaling mechanisms are critical to human adaptability and survival. Without these signals, I believe that the non breastfed children will lose out on the ability to have a more nuanced adaptable approach to health. They are beholden to the constant macro and micro nutrient makeup of the milk as well as the slow evolution of what is added back to it based on the molecular understanding of what is in breastmilk.
What do we know about the differences of these two milk types?
Human milk is dynamic on a minute to minute and day to day basis which is not so for formula. Human milk is plastic and capable of responding to external forces in the environment by the mammary glands ability to change the levels of hormones, macro and micro nutrient makeup and immune factors to give the infant a selective survival advantage in whatever environment the maternal child dyad is found in. Formula has no ability for change. It is a static calorie source without any ability to follow the child's needs and also cannot affect immune function in a positive way.
Human milk has two classes of protein: casein and whey. The casein protein curdles in the stomach when acid mixes with it. Whey remains as a liquid in the stomach acid and is easier to digest. Breastmilk is composed of between 50 and 80% whey protein depending on the date post partum. The whey/casein ratio in human milk fluctuates between 70/30 and 80/20 in early lactation and decreases to 50/50 in late lactation. In cow’s milk formula, the whey protein component is only 18%. Thus, cow milk formulas are much higher in casein than human milk, making them harder to digest compared to human breast milk. We are seeing this play out in clinic all of the time with children struggling with immunologically tolerating the casein protein. They present colicky and congested with loose green stools, reflux and eczema of the skin. Removal of the dairy protein is curative.
Other proteins present in breast milk include, lactoferrin and lysozyme, which prevent the growth and colonization of pathogenic bacteria which in turn reduces intestinal inflammation while also preventing illnesses. The maternally derived IgA antibody inhibits bacterial growth while sitting inside the mucous layer of the mucosal surface of the gut. These actions all have an immune balancing effect to induce tolerance to normal proteins in food and the environment which in turn prevents allergic and autoimmune types of disease.
One specific amino acid is also highlighted as a difference between milks. Glutamine, the most abundant free amino acid is important for providing ketoglutaric acid for the citric acid cycle which generates energy eventually, acting as a neurotransmitter in the brain and serving as a major energy substrate for intestinal epithelial cells to maintain a normal intestinal barrier. Glutamine is critical to prevent leaky gut and intestinal inflammation. Glutamine abundance varies from low in the early stages as colostrum to 2 log fold higher in mid to late first year of life. Again, formula has a static amino acid profile that cannot adjust to the child's needs.
Fats make up 4% of breast milk of which 95% is made up of triglycerides which is the storage form of fat. The other critical fat in the remaining percentage is the polyunsaturated fats known as PUFAs, linoleic and alpha linolenic acid. The most important of which is EPA and DHA which are precursor molecules to resolvins and protectins which decrease inflammation broadly after an insult especially in the brain.
Eighty percent of brain's DHA is acquired from the 26th week of gestation until birth. Premature babies lack the enzymes to convert the PUFA fats to the DHA and EPA which poses a great risk to these early babies. Mothers provide these fats during pregnancy and through breast milk assuming that she herself has adequate stores. Thus, it is critical that premature infants receive some breastmilk to prevent disease like Necrotizing enterocolitis from the dysbiosis.
Breastmilk provides for over 220 milk oligosaccharides (HMO) or small sugars that are indigestible by the human infant but are digestible by the infants intestinal microbes. This is an incredible evolutionary task for a mother to use her energy to make a food source for bacteria that is roughly 15% of breastmilk composition. The reason is clear. There is a profound symbiosis between a human and the intestinal microbiome. As discussed in the podcast with Dr. Shafizadeh, the specific intestinal microbes that are present in the intestines will dictate which HMOs' are metabolized and thus conferring health benefits to the child. Breastmilk is loaded with diverse HMO's and are giving a child the best health outcomes. Formula has recently added 2 HMO's out of the 220+ in order to meet this scientific health understanding. Thus, with the lack of diversity, it is only a matter of time until we learn about all of the missing benefits of the other HMO's in breastmilk.
This is by no means an exhaustive view of the disparate nature of formula and breastmilk, however, it shows a distinct difference and a lack of flux with formula as opposed to breastmilk. Science has clearly dictated that where and when possible, breastfeeding should be encouraged, supported and promoted nationwide.
Ballard Pediatric Clinics North America
Bravi American J Clin Nutrition
Robertson Cell Trends in Microbiology
Hegar Pediatric Gastro Hepatology
Breastfeeding CDC Report
Klein Evol Med Pub Health