Most of us are scared to death of bacteria and other “bugs.” They create a lot of misery and illness, we are told. So we wash our hands ad infinitum, and disinfect everything in sight. We need to kill all the bugs, don’t we?
No, we don’t.
Even if we wanted to, we could not come close to killing all of them. Because our bodies harbor about 100 trillion of them, on average. They are bacteria, viruses, and fungi. They live on our skin, in our mouths, and in our intestines. They outnumber the cells of our body by 10:1.
What are they?
These are tiny microbes which have been evolving for tens of thousands of years. And they are a diverse lot.
My gut microbes are different from yours. Their composition depends on multiple factors, including personal hygiene, genetics, diet, and antibiotic therapy, among others.
Do they have names?
Many of the gut microbes have no names or descriptions at present. Research into this field is still at an early stage.
What do they do?
These micro-organisms create byproducts, which enter our bloodstreams. It is suspected that they can be of significant benefit to us, but can also carry a potential for harm.
Some of these byproducts have anti-inflammatory effects. Some are anti-oxidants. They affect the health of the lining of our intestine. They are also felt to play a role in metabolic disorders, and influence immunity.
These bugs are also a manufacturing powerhouse.
Exercise and gut bacteria
Preliminary data suggest that athletes who exercise vigorously have a greater variety of microbes living in their guts. Greater diversity in gut microbes is generally believed to be beneficial.
Athletes have also been shown to have low levels of inflammation markers in their blood. Some rugby players have demonstrated large numbers of bacteria (Akkermansiaceae) shown to be associated with a low risk of obesity in previous trials.
On the other hand, researchers looking at non-athletic healthy men doing light exercise, and also overweight or obese sedentary men, found high blood levels of markers of inflammation and relatively low numbers of Akkermansiaceae bacteria.
So exercise appears to have a positive effect on gut bacteria. And this is beneficial for general health.
Obesity and the gut microbiome
We have all seen people who appear to eat a lot and never put on weight. How can that be possible?
The obese mouse
Believe it or not, if you take the microbes from the gut of an obese mouse, and give them to a slim mouse, that mouse also becomes obese. And vice versa.
So clearly, there is some connection between gut bacteria and weight issues. At least in mice.
Of mice and…men?
The pan-European HIT consortium organized a study on nearly 300 volunteers from Denmark. These volunteers included both lean and obese people.
The diversity of their gut flora was then analyzed and correlated with signs of metabolic problems.
People with low diversity in gut flora had more insulin resistance (which can lead to type 2 diabetes), higher levels of inflammation markers, and other warning signs of metabolic disorders.
Obese volunteers who also had low diversity in gut flora put on significantly more weight over 9 years of follow-up compared to other participants.
Bugs work with your diet?
A French study organized by the ANR MicroOrbes group evaluated the effects of a low-calorie diet on obese and overweight people.
The people who had low diversity in their gut bacteria at the beginning of the study improved significantly with the diet. The signs of metabolic disorders improved, and their bacterial diversity also got better.
The improvement with diet was not as significant in people whose gut bacterial diversity levels were already high to begin with.
Timing of bacterial colonization
A baby in the uterus has a sterile gut. Shortly after birth, bacteria, viruses and fungi begin to move in.
As solid food is started, and the baby is weaned from breast milk, there is a change in the composition of the microbial guests. By the age of 3 years, the baby’s gut microbes are fairly similar to the parents’. Incidentally, couples living in the same house tend to have similar flora in their intestines.
Manufacturing via bugs
The gut microbes are involved in the production by the body of several important substances, such as amino acids (building blocks of proteins), short -chain fatty acids, Vitamin K and B series, and chemicals needed for signal transmission in the brain, like serotonin.
Appetite
It also appears that the gut bacteria produce chemicals which act as signals affecting our digestion, appetite, and sensations of “fullness,” or satiety.
Milk and bugs
The nature of your gut bacterial colony depends heavily on your diet.
There is a difference between the gut flora of bottle-fed babies and breast-fed babies. Mother’s milk is a prebiotic, or a food for the gut microbes, which are helpful for the babies. It is also a probiotic, containing colonies of helpful microbes being put into the baby’s body.
Bottle-fed babies have intestines which have suboptimal colonization by helpful microbes. It is possible that these babies have inadequate protection against some diseases.
Diet and bugs
Whole grains, fiber, and the presence or absence of meat and processed foods in our diet affects the composition of our guts’ tiny resident guests.
The Western gut is less diverse than the Eastern one, and the rural gut also looks different.
Does this affect the incidence of chronic diseases and metabolic diseases so much more common in the West? It is too early to tell.
Conclusions
- It is time to stop thinking of “me,” and start thinking of “my bugs & I.”
- A diverse group of gut bacteria are essential for our health.
- Diet, genetics, and lifestyle play a vital role in our intestinal composition.
- Many diseases, especially chronic diseases common in the West, might be linked to poor protection from a less diverse gut microbial flora.
- More research is necessary, and is ongoing, to clarify the association of gut bacteria and serious diseases.
- Obesity and gut bacteria may well be linked.
Stay tuned!
In a subsequent post, we will discuss:
- Antibiotics and gut bacteria
- Cesarian section births and gut bacteria
- Artificial sweeteners and gut bacteria
- How to look after your gut bacteria and
- Other relevant issues.
interesting information.