I have taken the following facts from a paper that was published in the New York Times, based on the article: Important Facts: Breastfeeding the Microbiome, by Ed Yong, July 22, 2016. Elements
The 3rd most plentiful ingredient in human milk after lactose and fats, is Human milk oligosaccharides known as H.M.O. Research has found that babies cannot digest them, despite their structure being a rich source of energy. So then came the question by the chemist, Bruce German (famous for studying the components of human milk) …
Why would a mother use so much of her energy making these complicated chemicals if they were useless to her baby?
What else these could H.M.O’s could be used for?
He found that the H.M.O.’s pass through an infant’s stomach and small intestine undamaged and land in the large intestine, where most of our bacteria live. So, he hypothesised what if nature did not intend these H.M.O to be used as food for the baby, instead as food for the microbes that live in the large intestine.
Alongside this research, paediatricians were studying the stools of breast fed infants compared with formula fed infants and what they had found were microbes called Bifidobacterium (BIFS). These were more common in the stools of BF infants and they argued that human milk must contain some substance that nourished the bacteria. They called this the BIFIDUS FACTOR.
They assumed that the H.M.O.’s and the bifidus factor were one and the same and they nourished the gut microbes in the breast fed baby. It is now the 1990’s and we now know that there is more than a hundred H.M.O.’s in human milk, but only a few had been characterized. German was not satisfied with not knowing what each specific H.M.O.’s looked like. It was assumed that all the H.M. O’s nourished all the species of bacteria (BIF’s) equally. But… German thought otherwise. He wanted to know which Human Milk Oligosaccharide was feeding which Bifidobacterium.
SO…Together with a team of chemists, microbiologists, and food scientists, German identified all the H.M.O’s, and pulled them out of the human milk and fed them to all the bacteria, but to their surprise nothing grew. They concluded that H.M.O’s are not an all- purpose food for the BIF’s and in 2006, the team found that the sugars (HMO) selectively nourish one subspecies, BIFIDOBACTERIM LONGUM INFANTIS.
If you provide this specific B.Infantis with H.M.O’s it will outcompete any other gut bacteria. B.Infantis uses thirty genes to devour every scrap of H.M.O’s and no other bacterium has this genetic makeup, so nature has intended human milk to nourish this microbe.
What does this mean?? Well as it digests the H.M.O’s it releases short chain fatty acids, which feed an infant’s gut cells.
These gut cells are fed so that they can make adhesive proteins which keep microbes out of the blood stream and out of the ant inflammatory molecules that regulate the immune system. These changes only happen when B. Infantis feed on H.M.O’s.
The second thing that happens is the release of sialic acid, and we know that the human brain depends on sialic acid for growth. Our brain is very large for a primate, and the growth in the first year of life is extremely fast. Another researcher ( David Mills) has hypothesised that the reason why human breast milk contains 5 x as many HMO’s as cow’s milk is to fuel this growth.
So, by keeping the bacterium well fed we can raise brainier babies. Our evolution from ape to man. Food for thought! As there is only these H.M.O’s in breast milk, the microbe’s full potential is only unlocked when it feeds on breastmilk. So, these Nourishing, inflammatory and anti-infective process that happen when Bacterium infantis consumes H.M.O.’s are setting up the foundations of our immune systems and brain development.
I know it all sounds very technical and it has taken me some time to sift through all my lecture notes on this topic to try and simplify it as much as I can without losing the main objective. I love a good scientific rationale for explaining something that has been intuitively know for some time!
Hamlet
So, the second thing that research is trying to explain, is how breast fed infants and mothers are less likely to develop some types of cancers. Again, it is a very complex hypothesis and the research articles are a bit to in depth for our purposes. It can be researched further by doing a literature search on HAMLET as it is quite fascinating. Breastmilk contains a compound called HAMLET (Human Alpha- lactalbumin Made Lethal to Tumour cells). HAMLET is formed when the protein: alphalactalbumin, is mixed with a fatty acid called oleic acid at a low PH. It can attack cancer cells by reducing the strength of the cancer cells outer defence mechanism, or by targeting the cancer cells mitochondria (power house) and effectively deleting the information contained in its nucleus. This causes the cancer cell to lose energy and memory and it dies in a process called apoptosis. The scientists have been busy working on mice to discover that this HAMLET can kill or limit the development of brain, colon and bladder in genetically susceptible mice and can kill over 40 different types of cancer. The other amazing thing they have discovered is that only targets and kills cancer cells, leaving the healthy cells unharmed, unlike chemotherapy. As they are finding out more and more about HAMLET, the newest hypothesis is once again it is the infants gut that promotes the formation of HAMLET due to the perfect PH balance of a breastfed gut, the environment is perfect to produce HAMLET and they now wonder if that is why childhood cancers such as leukaemia and lymphomas are less prevalent in a breast-fed child.