Most people think that bacteria or microbes are “bad,” that “bacteria are nasty, bacteria make us sick. We must get rid of them.”
So, unwittingly, mothers refuse to put their babies on the floor, setting them up for motor deficiencies later on in life or buy special soaps to kill bacteria and thereby contribute to antibiotic resistance and beg complacent doctors to prescribe antibiotics which end up wiping out helpful gut bacteria.
All bacteria are not bad. We may think all of the cells in our body are human but in 2012 Katrina Ray, a senior editor of Nature Reviews, seriously asked the question, “are we more microbes than man?”
It turns out that there are more bacteria in and on our body than we have human cells. Microbes outnumber our own human cells ten to one. Every one of us is host to about 100 trillion bacteria, which all together weigh around three pounds.
Are we just carriers for a mass of micro organisms housed in a human shell then? Or are we, as has been argued, “a superorganism, a communal collective of human and microbial cells working as one?”
The highest density of and diversity in these micro organisms is in our intestines, which is home to trillions of bacteria, collectively called the gut microbiota.
It includes about 1,000 different types of bacteria and this diversity is very important. Most of the bacteria in our gut are as specific to us as are our fingerprints, except that they can change.
We are not just on “friendly” terms with our gut bacteria, the relationship is infinitely more intimate than that, we are married to them.
We are colonised by bacteria from birth, and potentially in utero. Our mothers play a vital part in providing the first bacteria for the development of our resident microbiota, jump-starting the initial colonisation of our intestines and the rest of the human body through skin-to-skin contact and breastfeeding.
Babies who are born vaginally or breastfed have very different gut bacteria compared to babies who are born through Caesarian section or formula fed. These bacteria, unfortunately, are associated with disease.
Gut bacteria have a crucial role in nutrition and health. Their functions are considered so important to our life that the gut microbiota is now being likened to other human organs, similar to any other body part like the skin or brain or muscle or liver, a vast collection of cellular organisms that belong to us and work with us to produce a unique biological phenotype, us.
Some gut bacteria have a fundamental role in synthesising vitamins B and K.
Some assist with the absorption of salts and water. Others help in breaking down substances that the small intestine is not able to digest by itself and provide more energy to the human body. Obese individuals have been found to have an excess of these bacteria in their large bowel.
This now has to be factored into the “eat less, exercise more” equation of losing weight so beloved of physicians.
Some gut bacteria assist intestinal cells to grow and regenerate. Others secrete antimicrobial chemicals or regulate inflammatory cells. Most, simply by being present in the gut, prevent harmful bacteria from taking up residence.
Like societies all over the world, our gut microbiota is losing its diversity and that is having serious repercussions on our health. The distortion in the microbial balance in the human gut is increasingly linked to serious, chronic illnesses like inflammatory bowel disease (ulcerative colitis & Crohn’s); celiac disease (gluten intolerance); nonalcoholic fatty disease; chronic reflux; Type 1 diabetes; obesity; cancers (colon, liver and pancreas); cardiovascular disease; autoimmune diseases like multiple sclerosis and rheumatoid arthritis; and asthma and allergies.
The causes for this change in gut bacteria, from helpful bacteria to harmful bacteria are many and include, as suggested above, Caesarian sections and infant formula feeding, antibiotics and diet.
Diet, whether early (breastfeeding vs formula) or later (processed vs natural food), plays a crucial role in the development of a healthy microbiota.
Most people are aware of this. Caesarian sections and antibiotics may come as a surprise. But look at the association between Caesarian sections and obesity.
Babies born by Caesarian section are much more likely to be overweight or obese as adults than those delivered vaginally. Caesarian sections encourage the growth of bacteria in the gut from the mother’s skin or worse, from the attending doctor or nurse, rather from the birth canal and these bacteria encourage absorption of energy from the gut.
Antibiotics pretty much wipe out most of the bacteria in the gut, helpful or otherwise. This allows other types of bacteria to colonise the gut, affecting some of the functions above and potentially giving rise to the diseases mentioned.
Antibiotics should be used carefully. I would think most children in T&T have received an average of two to three antibiotic courses a year by the time they start primary school. This cannot be good.
Gut bacteria from healthy individuals have become so important to our health that preliminary attempts are being made to transfer these bacteria to ill persons with successful outcomes in some cases.
If we can ever get over the “yucky factor,” then perhaps faecal microbiota transplantation may one day take its place among the other forms of organ donation.
There might be a better way to do it though: through human milk or some of its thousands of components.