The Biome
There are 10 popular bacteria listed in the "Human environment" - "Biological environment" section of this website.
The human microbiome refers to the collection of microorganisms (such as bacteria, viruses, and fungi) that live in and on the human body. These microorganisms play a crucial role in human health and well-being, and their presence and diversity are essential for maintaining a healthy immune system, digestion, and overall physiology.
The human microbiome is composed of trillions of microorganisms, the majority of which are bacteria. These microorganisms are found in a variety of habitats on the body, including the skin, gut, oral cavity, and respiratory tract. The gut microbiome, in particular, is considered one of the most important and diverse microbiotic communities in the human body, with more than 1000 different species of bacteria.
The human microbiome plays a crucial role in many physiological processes, including digestion, metabolism, and immune function. For example, the gut microbiome helps to break down complex carbohydrates and fibres that are indigestible by human enzymes, and produces short-chain fatty acids that are essential for gut health. Additionally, the gut microbiome plays a role in the development and function of the immune system, and has been linked to the development of certain types of cancer.
As many as 90% of our cells are bacterial. In fact, bacterial genes outnumber human genes by a factor of 100 to one.
The gut is an immensely complex microbial ecosystem with many different species of bacteria, some of which can live in an oxygen-free environment. An average person has approximately 1.5 kilograms of gut bacteria. The term “gut microbiota” is used to describe the bacterial collective.
Gut microbiota send signals to the brain via the brain-gut axis and can have dramatic effects on animal behaviour and health.
In one study, for example, mice that were genetically predisposed to obesity remained lean when they were raised in a sterile environment without gut microbiota. These germ-free mice were, however, transformed into obese mice when fed a faecal pellet that came from an obese mouse raised conventionally.
There is growing evidence to support the role of gut microbiota in influencing why we crave certain foods.
We know that mice that are bred in germ-free environments prefer more sweets and have greater number of sweet taste receptors in their gut compared to normal mice. Research has also found that persons who are “chocolate desiring” have microbial breakdown products in their urine that are different from those of “chocolate indifferent individuals” despite eating identical diets.
Many gut bacteria can manufacture special proteins (called peptides) that are very similar to hormones such as peptide YY and ghrelin that regulate hunger. Humans and other animals have produced antibodies against these peptides. This raises the distinct possibility that microbes might be able to directly influence human eating behaviour through their peptides that mimic hunger-regulating hormones or indirectly through antibodies that can interfere with appetite regulation.
The neurotransmitters and signaling molecules produced by gut bacteria that are thought to influence our food choices and preferences include:
Serotonin: A neurotransmitter that affects our mood and is involved in regulating appetite and satiety.
Dopamine: A neurotransmitter that is associated with pleasure and reward and can affect food cravings.
Ghrelin: A hormone that regulates appetite and is involved in promoting food intake.
Leptin: A hormone that regulates energy balance and satiety.
Peptide YY: A hormone that regulates appetite and food intake.
Faecal transplantation is also now an accepted treatment for those patients that have a severe form of gut bacterial infection called Clostridium difficile, which has been unresponsive to antibiotics.
The use of such targeted strategies is likely to become increasingly common as we better understand how gut microbiota influence our bodily functions, including food cravings.
The human microbiome also plays a role in mental health, and is linked to various psychiatric disorders, including depression, anxiety, and autism. Studies have shown that changes in the composition of the gut microbiome can lead to changes in the brain and behavioural patterns, and that the gut-brain axis is a key mechanism in this relationship.
The human microbiome is constantly changing and adapting to the environment, and is influenced by various factors such as diet, antibiotics, stress, and environmental toxins. The balance and diversity of the microbiome are important to maintaining good health, and disruptions to the microbiome, known as dysbiosis, can lead to various health problems.
Overall, the human microbiome is a complex and dynamic ecosystem that plays a crucial role in maintaining human health and well-being.
Several strains of bacteria have been identified that are capable of producing and releasing neurotransmitters such as GABA and glutamate. Here are a few examples:
Lactobacillus brevis: This bacteria species is commonly found in fermented foods such as kimchi, sauerkraut, and pickles. It has been shown to produce GABA in the gut, and studies have found that consumption of Lactobacillus brevis-containing foods can lead to an increase in GABA levels in the blood and brain.
Bifidobacterium dentium: This bacteria species is commonly found in the human digestive tract and has been found to produce glutamate. Studies have suggested that Bifidobacterium dentium may play a role in the regulation of glutamate levels in the gut and brain.
Streptococcus thermophilus: This bacteria species is commonly used in the production of yogurt and other fermented dairy products. Studies have found that Streptococcus thermophilus is capable of producing GABA, and consumption of Streptococcus thermophilus-containing yogurt has been found to increase GABA levels in the blood and brain.
Lactobacillus rhamnosus: This bacteria species is commonly found in the human digestive tract and has been shown to produce GABA. Studies have found that consumption of Lactobacillus rhamnosus-containing foods or supplements can lead to an increase in GABA levels in the blood and brain.
Some of the bacteria that are capable of producing neurotransmitters such as GABA and glutamate can establish long-term colonies in the gut, while others may be more transient.
For example, several strains of Lactobacillus and Bifidobacterium, which are known to produce GABA and glutamate, respectively, are commonly found in the human gut and can establish long-term colonies in the digestive tract. These bacteria are part of the normal gut microbiota and can play important roles in maintaining gut health and promoting overall health.
However, the composition of the gut microbiota can be influenced by various factors such as diet, stress, antibiotic use, and other environmental factors. Changes in the gut microbiota composition can affect the presence and abundance of these bacteria and potentially impact the production of neurotransmitters such as GABA and glutamate.
There is more bacterial and viral genetics than human genetics in a typical human body. According to some estimates less than 10% of the genetic material inside us is human.
Things that work with human biology ranges from friendly bacteria, virus, chemical nutrients, water to more complex stuff including other humans.
Microbiome Journal can inform you more.
Defining the human microbiome might also be worth a look if you are interested.
An excellent source of good quality information on virus in particular but also including genetic evolution, immunology and other various goodies that experts discuss is MicrobeTV, hosted by Professor Vincent Racaniello.
We are made of what we eat.
Just like all other life we rearrange the atoms and molecules we consume to fit in with our own genetic plan of things.
Some chemistry like food and medicine fits lovely with our genetic plan and some, like poisons and pathogens, don't fit nicely at all.
Things that fit lovely can become poisonous and pathogenic if they become too abundant. Even clean water will kill us if we consume to the extreme.
As far as diet is concerned, balance and variety seems to be the main factors to consider in order to maintain a healthy body.
If you need to be an extremist be extremely balanced. Balanced things last longer in nature.
The gut microbiome has a significant influence over the types of foods that people want to eat. Research has shown that the gut microbiome can affect food cravings and preferences through various mechanisms, such as the production of hormones and neurotransmitters that regulate appetite and metabolism. Additionally, the gut microbiome can impact the way that the body processes and absorbs nutrients from food, which can also influence food choices.
Studies have also shown that different types of gut bacteria are associated with different dietary preferences, and that changes in the gut microbiome can lead to changes in food cravings and preferences. For example, studies have found that people with a higher proportion of certain types of gut bacteria, such as Bacteroides, tend to prefer high-fat, high-protein diets, while people with a higher proportion of other types of gut bacteria, such as Prevotella, tend to prefer diets high in carbohydrates.
In conclusion, the gut microbiome can play a significant role in determining what types of foods people want to eat, and further research in this area could lead to new insights into the underlying mechanisms and potential ways to influence food choices.
The most common gut microbes include:
Bacteroides: This is one of the most abundant groups of bacteria in the gut, and is associated with the breakdown and fermentation of complex carbohydrates.
Firmicutes: This group of bacteria is known for its ability to ferment carbohydrates and extract energy from them.
Actinobacteria: This group includes bacteria that are important for breaking down complex compounds, such as plant fibers and complex sugars.
Proteobacteria: This group includes a diverse range of bacteria, some of which are associated with inflammation and disease.
Verrucomicrobia: This group of bacteria is known for its role in breaking down complex carbohydrates and producing short-chain fatty acids.
Fusobacteria: This group includes bacteria that are associated with various digestive processes, such as the breakdown of bile acids.
Euryarchaeota: This group of archaea is known for its ability to produce methane, and is associated with the fermentation of complex carbohydrates.
Bifidobacterium: This is a group of bacteria that are known for their beneficial effects on human health, such as the production of short-chain fatty acids and the stimulation of the immune system.
These are some of the most common gut microbes, and the composition of the gut microbiome can vary greatly between individuals and can be influenced by factors such as diet, lifestyle, and genetics.
A healthy gut biome is characterized by diversity and balance, and is composed of a wide range of different microorganisms that work together to maintain the health of the gut and the overall health of the body.
The components of a healthy gut biome include:
Diverse microorganisms: A healthy gut biome contains a diverse range of bacteria, viruses, fungi, and other microorganisms, each of which plays a specific role in maintaining gut health.
High abundance of beneficial bacteria: Beneficial bacteria, such as Bifidobacterium and Lactobacillus, are key components of a healthy gut biome. These bacteria help to maintain a healthy balance of gut microbes, support digestive health, and promote the production of short-chain fatty acids that provide energy to the gut lining.
Low abundance of harmful bacteria: A healthy gut biome contains low levels of harmful bacteria, such as Escherichia coli and Salmonella, which can cause infections and disrupt the balance of gut microbes.
Good balance of Firmicutes and Bacteroidetes: These two groups of bacteria are the most abundant in the gut and play key roles in the digestion and absorption of food. A healthy gut biome contains a good balance of both Firmicutes and Bacteroidetes.
High level of gut microbiota stability: A healthy gut biome is characterized by stability, meaning that the composition of gut microbes remains relatively constant over time, even in response to changes in diet or other environmental factors.
Adequate amount of dietary fibre: A healthy gut biome is dependent on a diet that is rich in fibre, as fibre provides the essential nutrients that support the growth and survival of gut bacteria.
In conclusion, a healthy gut biome is characterized by diversity, balance, stability, and the presence of a high abundance of beneficial bacteria, low levels of harmful bacteria, and an adequate intake of dietary fibre.
