Human milk: nutrient and beyond

Mother's milk. 

Babies will cry for it when they want it and want it fast. 

But it's not just a matter of pure hunger or an egocentric desire. There's a big biological reason behind the baby's need for breast milk. 

Human breast milk is recognized as thenutritional ‘gold standard’ for infants. It contains all the essential nutrients they need for healthy growth and development¹.

The contents of breast milk are complex. While it may seem straightforward, the composition of breastmilk is quite dynamic. It varies within a feeding, diurnally, over lactation, and between mothers and populations.² 

Amazingly, the breast milk adapts to the nutritional needs of an individual infant and will varyover time. The mother’s body knows exactly what the baby needs and naturally formulates it in the breast milk, which contains protein, fats, sugar, vitamins, minerals, and many protective bioactive components. 

It's like an automatic made to order milk that's biologically catered to the precise demands of an infant's system. 

Due to this variability, the nutritional content of breast milk is typically provided as average values of nutrients in mature breast milk. 

• Lactose: Milk sugar, known as lactose, is the primary carbohydrate in breast milk. Human milk contains more lactose than cow's milk. Carbohydrates are a preferred energy source for the brain.

• Fats: Fats are a major source of energy. Fats only make up about 4% of breast milk, but they provide over half of the calories that your baby receives from breast milk. Fats also provide the infant with essential fatty acids and long chain polyunsaturated fatty acids (LCFAs), which help to develop the baby's brain, nervous system, and vision. 

• Human Milk Oligosaccharides (HMO): HMOs are the third largest solid component in breast milk after fat and lactose. They are a group of non-nutritive components that range from three to 32 sugars in size. One of the major benefits of HMOs is to encourage the growth of ‘good’ bacteria in the baby’s gut, which is where 70% of the immune system is located. HMO also protects your baby against infection at a time when they are most vulnerable.

• Proteins: The proteins in breast milk are easy for babies to digest and they are essential for infants’ healthy growth and development. Protein helps to build, strengthen, and repair the body's tissue, as well as the production of hormones, enzymes, and antibodies. There are two major types of protein present in mature breast milk: whey (60%) and casein (40%). Breast milk also provides lactoferrin, which has antibacterial and immune stimulating function.

• Minerals and Vitamins: Breast milk contains a wide range of vitamins and minerals needed to support your baby's health as they grow. Vitamins are important for the immune system and needed for energy and protein metabolism. They are also involved in blood clotting and support healthy bones, eyes, and skin. Minerals are used to maintain proper fluid balance, build strong bones and teeth, produce red blood cells, and promote proper muscle, nerve and immune function.

Beyond the Nutrients: Bioactive Substances and Human Milk Oligosaccharides (HMO)

Not only is breast milk a complete source of nutrition and hydration, but it also contains hundreds to thousands of bioactive substances that protect against infection and inflammation and contribute to immune function, organ development, and healthy gut microbiota.²These bioactive substances include immunoglobulins, oligosaccharides, insulin, lactoferrin, lysozyme, cytokines, epidermal growth factors, leukocytes, nucleotides and bacteria.³

Yeah, it's a lot. 

So by now, you can likely see that breast milk is far more complex and nutritive than the off-the-shelf cow's milk you find at the grocery store. 

Both are whitish liquids. The similarity ends there. 

One of the most studied bioactive molecules from breast milk is the HMO. HMOs make up as much as ten percent of human milk, which is even higher than protein.  Surprisingly, the third most abundant component of human milk (HMOs) has virtually no nutritive value, but provides unique benefits and exerts lifelong impact on overall health.

HMOs are essential to infants’ growth and development. They stimulate the immune system, support brain development, and provide protection against diseases. These health benefits are achieved both directly through the interaction of the gut epithelial cells and indirectly through the establishment of the gut microbiota as prebiotics.

There can be more than 200 different varieties ofHMOs in human breast milk. HMOs are unique and differ in composition from any other mammal.⁴ Among the various compositional differences between human breast milk and cow’s milk, is the presence of HMOs in human milk, which are virtually absent in cow milk and infant formula.⁵ 

Human breast milk contains three major HMO types: fucosylated HMOs (35%–50%), sialylated HMOs (12%–14%), and nonfucosylated neutral HMOs (42%–55%). Amongst the synthesized HMOs, 2′-fucosyllactose (2′-FL) and lacto-N-neotetraose (LNnT) are widely studied and are considered safe for infant nutrition.⁶

How and what the infant is fed influences the development and competence of the immune system.⁷ Through unique nutritional composition and bioactive substances, human milk supports healthy growth and protects the infant during this vulnerable period. 

How to get HMOs

There are a couple great HMO products for adults available quite conveniently through Amazon.com

• PureHMO™ Prebiotic Capsules have 1300mg of human milk oligosaccharide per serving and sell for just $20.89 on Amazon
• PureHMO™ Prebiotic Powder is the same product in straight powder form ready to be scooped into drinks. With this version you avoid the collagen capsule and get faster absorption into your system. It sells for $28.99 on Amazon

References:

1. Spencer, Rachael, Sheila Greatrex-White, and Diane M. Fraser. "I was meant to be able to do this’: A phenomenological study of women’s experiences of breastfeeding." Evidence Based Midwifery 12.3 (2014): 83-88.
2. Ballard, Olivia, and Ardythe L. Morrow. "Human milk composition: nutrients and bioactive factors." Pediatric Clinics60.1 (2013): 49-74.
3. Yahaya, Tajudeen, and Ufuoma Shemishere. "Association between Bioactive Molecules in Breast Milk and Type 1 Diabetes Mellitus." Sultan Qaboos UniversityMedical Journal20.1 (2020): e5.
4. Newburg, David S., Guillermo M. Ruiz-Palacios, and Ardythe L. Morrow. "Human milk glycans protect infants against enteric pathogens." Annu. Rev. Nutr. 25 (2005): 37-58.
5. Bode, Lars. "Human milk oligosaccharides: every baby needs a sugar mama." Glycobiology 22.9 (2012): 1147-1162.
6. Hegar, Badriul, et al. "The role of two human milk oligosaccharides, 2′-fucosyllactose and lacto-N-neotetraose, in infant nutrition." Pediatric gastroenterology, hepatology & nutrition 22.4 (2019): 330-340.
7. Donovan, Sharon M., and Sarah S. Comstock. "Human milk oligosaccharides influence neonatal mucosal and systemic immunity." Annals of Nutrition and Metabolism 69.Suppl. 2 (2016): 41-51. 

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