December 26, 2018December 26, 2018 by evanengelstad

Breastfeeding is Unbelievable!

I am a 31-year-old married man. I do not have mature mammary glands. (Yet.) I do not have a thirsty newborn. But I do have an insatiable interest in breastfeeding after reading a fascinating article in The Stranger entitled “The More I Learn About Breast Milk, the More Amazed I Am.” I fell deep into the rabbit hole and this blog post attempts to scratch the surface of the amazing topics of breastfeeding and breast milk. It is our first food source, fully customized and full of specialized elements. Perhaps we can learn more about adult nutrition by examining its composition. Researching breast milk has decidedly strengthened my appreciation of the human body and everything it does without our even thinking or knowing about it. I hope you enjoy the following remarkable aspects of breast milk.

Composition of Breast Milk

If you sold human milk in stores, could you put an accurate nutrition facts label on it? What are the ingredients of breast milk, anyway? Well, “it depends.” It depends on the age of the infant. It depends on if the baby was born preterm or not. It depends on the diet of the mother. It depends on the immune status of mother and child. It even depends on the gender of the baby! All of these factors (and more) can change the composition of human milk.

Stages of Development

The composition of breast milk is constantly changing depending on the needs of the baby. In terms of macronutrients, for example, the protein composition of breast milk tends to go down gradually as the infant gets older. The first milk a mother produces – colostrum – is full of immune factors that help build a baby’s immune system and prebiotics to help grow the baby’s microbiome. As the infant grows, the composition of milk shifts to become richer in calories (fat and carbohydrates) and less rich in immune proteins. And in premature babies, mothers tend to produce higher protein and fat milk (perhaps to help them catch up and grow quicker).

Diet of Mother

The fatty acid composition of breast milk is much more dependent on the mother’s diet than the carbohydrate or protein composition. Drawing from Milligan and Bazinet’s research, Katie Hinde summarizes in her fascinating blog post “How Special is Human Breast Milk? Part II”

Women consuming a “Western” diet have 0.32% DHA (omega-3) in milk, whereas women consuming a lot of fish have 0.93% DHA, but vegetarian and vegan women have 0.22% and 0.14% DHA respectively.

DHA stands for docosahexaenoic acid, a conditionally essential fatty acid. In order to be optimally healthy, humans need to consume two types of essential fatty acids: linoleic acid (LA) and alpha-linolenic acid (ALA). ALA is converted to DHA in the human body so that it can be used in brain and retina tissue, as well as to create anti-inflammatory prostaglandins. Most people do not efficiently convert ALA to DHA and thus need to consume more preformed DHA in their diet. Due to DHA’s importance in the neurodevelopment of growing infants, it is important for nursing mothers to have sufficient levels of DHA in their breast milk. Eating fish is one proven way to accomplish that. An excellent article by Arthur Haines entitled “Why You Should Consume Seafood Despite the Warnings” might help you decide whether or not to eat fish in the face of warnings about mercury and other pollutants in fish. And DHA status does not just affect infant brain and retina development. Analysis of two clinical trials showed that pregnant women are less likely to have preterm births if they have sufficient DHA status.

The mother’s diet not only affects the macronutrient composition of breast milk, but also its taste! Leave it to Canadians to use a trained panel of adults to taste test breast milk from different mothers. Elizabeth Barker noted in the abstract of her dissertation entitled “Sensory Characterization of Human Milk”

Off-flavours noted in fresh human milk were described as metallic, fruity, sour and spicy. Frozen milk, subject to more frequent and more intense off-flavours, was described as metallic, cardboardy and soapy.

More recent research looking at differences between bottle fed and breastfed infants shows that babies can indeed taste differences in flavor and that it can influence their later experience of food. For example, mothers who recently ate spicy food create more “peppery” breast milk which in turn conditions their babies to develop a taste for the flavor that appears to continue into adulthood.

Gender

It turns out that in some cases, mothers make more energy-dense and fat-rich breast milk for baby boys than for baby girls. However, it may be that baby girls get a higher volume of breast milk from mothers so that the energy density is the same regardless of gender. The research is fairly sparse and has limitations, but it brings up an important question: if an infant does not have access to breast milk, do we need to have separate formula options depending on gender?

Immune Status of Infant

In another amazing blog post by Katie Hinde, she lays out the scientific plausibility of how the composition of mother’s milk can rapidly adapt to the immune needs of the infant. Here is how it basically works. While suckling, negative pressure is created around the nipple that takes a mixture of baby saliva and breast milk back into the milk ducts. This explains how a mother can then create breast milk with specific immunofactors to help the infant fight off an infection that the mother does not have. The combination of breast milk and baby saliva also creates a chemical reaction resulting in the formation of hydrogen peroxide that helps prevent harmful bacteria from growing and encourages the growth of helpful bacteria. Breast milk is an amazing mixture of not only lactose, fatty acids, and proteins, but of micronutrients, growth factors, hormones, immune factors, bacteria, and even stem cells!

In Part II of this blog post, I will compare breastfeeding to bottle feeding and how it can affect infant mortality, intelligence, and even the structure of the jaw. I will also dive into the Nestle controversy and boycott. Stay tuned!