....the strains and species of the mother's vagina that are most similar to those colonizing the newborn's gut...These vaginal microbes are quite a select bunch - far less diverse than those in the mother's gut - but they seem to have a specialist role in the newborn's developing digestive tract...They are part of a group known as the lactic acid bacteria.
The vagina's lactic acid bacteria are milk eaters. They take the sugar found in milk, lactose, and convert it into lactic acid, creating energy for themselves in the process. Babies are also milk eaters, converting lactose into glucose and galactose, which are absorbed by the small intestine into the blood and then converted into energy for the baby. Any lactose that makes it past small intestine undigested is not wasted. It goes straight to the lactic acid bacteria waiting in the large intestine.
...The bacterial communities living in pregnant women's vaginas are different ones from those living in the vaginas of non-pregnant women. Among the normal species of the vagina are species more normally found in the gut...During pregnancy the vaginal microbiota shifts, growing less diverse...When a babies is colonized, its gut microbes are relatively diverse, including some of mum's fecal bacteria as well as the vaginal set. But this initial collection also rapidly slims down to just those bacteria that can help with milk digestion.
The early colony that takes up residence in a baby's gut forms a crucial starting point for the microbiota that will develop over the next few months, possibly setting the trajectory for several years.
...millions of babies are born each year without going anywhere near their mothers' vaginas. In some places, giving birth by Cesarean section is more common than giving birth vaginally.
...Cesarean babies are more susceptible to infections. Up to 80 percent of cases of Methicillin-resistant Staphylococcus aureus (MRSA) infections in newborns occur in those born by Cesarean. As toddlers, children born by C-section are more likely to develop allergies.
...Sampling the gut microbiota of babies can reveal whether they were born by C-section or vaginally for many months after their birth...But whereas the microbiotas of mother's vagina and the child's gut match following a natural birth, C-section babies and their mums cannot be matched up by looking at their microbes.
Even vaginal births are relatively germ-free affairs in the Western world...Beds, hands and tools are all washed with antibacterial soaps and alcohol rubs before they come into contact with the laboring woman or her baby...and there is no doubt that many thousands of mothers and babies are alive because of such hygiene.
Lactose intolerance is the inability of some people to break down the milk lactose using lactase enzyme...There was a difference in the amount of hydrogen in the breath of colicky and non-colicky babies...Excess hydrogen in the breath indicates that bacteria in the gut are breaking down food...If bacteria were producing hydrogen, they must have been receiving a sizable meal.
Oligosaccharides (Oligo- means few) are carbohydrates made up of short chains of simple sugars...They are manufactured in the breast tissue of pregnant and breast-feeding women...Bifidobacteria in microbiota of breast fed babies make enzymes the can use oligosaccharides as their sole food source. As a waste product, the produce the all-important short-chain fatty acids (including lactic acid) that is particularly valuable in babies. These feed the cells of the large intestine, and play a crucial role in the development of a baby's immune system.
Before pathogenic bacterium can do any damage, it must adhere to the intestinal wall using special attachment points on the bacterial surface. Oligosaccharides fit perfectly into these points, depriving nasty species of a foothold.
Checking the blood for migrant microbes shows the route they took. They are stowaways, travelling inside immune cells called dendritic cells. The dendritic cells are willing participants in the trafficking of the bacteria. Sitting among the dense immune tissue that surrounds the gut, these cells are able to reach out with long arms into the intestine to check what microbes are present. Usually, they are responsible for engulfing pathogens, then waiting for another team of immune cells (natural killer cells) to turn up and destroy them. Extraordinarily, the dendritic cells can also pluck unsuspecting beneficial bacteria from among the crowd to engulf and transport through the blood to the breasts.
The microbial content of the colostrum of women who delivered by pre-labor elective Cesarean section is strikingly different from that of women who delivered vaginally...But in women who had in-labor emergency C-sections, the milk microbiota was far more similar to that of mums who delivered vaginally. Something about the labor process sounds a signal, informing the immune system that it is the time to prepare for the baby to be on the outside of the body...many powerful hormones released during labor. Their release alters which microbes are moved form the gut to the breasts in preparation for the emerging baby...
Bottle-fed babies are more prone to infections...Bottle-fed babies are also nearly twice as likely to develop eczema and asthma.
Breast feeding reduces women's risk of type 2 diabetes, high cholesterol, high blood pressure and heart attacks in later life.
Collen, A. (2015) 10% Human: How Your Body's Microbes Hold the Key to Health and Happiness. London: William Collins.
Bottle-fed babies are more prone to infections...Bottle-fed babies are also nearly twice as likely to develop eczema and asthma.
Breast feeding reduces women's risk of type 2 diabetes, high cholesterol, high blood pressure and heart attacks in later life.
Collen, A. (2015) 10% Human: How Your Body's Microbes Hold the Key to Health and Happiness. London: William Collins.
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