How The Gut Micro-organisms (Microbiome) Affects Metabolic Health

Nidhi Paresh Parekh
Nidhi Paresh Parekh
September 13, 2021

The human gut microbiome refers to the collection of microorganisms that resides in the gastrointestinal tract. About 100 trillion microorganisms, including both good and bad bacteria, line our gut and play a crucial role in the body. These microorganisms may protect from diseases but sometimes bacteria could predispose to a number of conditions, including but not limited to, obesity, type 2 diabetes, hypertension, colorectal cancer, and inflammatory bowel disease.

Why Do We Have A Gut Microbiome?

Our gut microbiome plays many crucial roles in our body. For example, the “good” bacteria act like our partners and play a central role in the breakdown and synthesis of nutrients, ensuring they are available to the body for absorption. The gut bacteria also play a vital role in immunity -- protecting our gut from “bad” bacteria and also promoting the integrity of the lining of the gut.

Mice that are grown in the laboratory in the absence of their gut bacteria show metabolic and immunological impairments, further demonstrating the importance of the trillions of occupiers of our body. These bacteria are so important to humans, that some researchers believe that a developing fetus in the mother’s womb is exposed to these bacteria via the placenta.

Throughout adulthood, the gut microbiome continues to grow and flourish. For this reason, a variety of factors can influence the composition of the gut microbiome. These factors include host genetics, immune responses, antibiotic usage, lifestyle, circadian rhythms, and the environment. Due to the intimate relationship between the microbiome and our body, any variations in the microbiota can cause harm to our body and lead to a myriad of diseases.

Throughout our lives, the gut microbiome may be harmed by low-fiber diets, high-sugar diets, medication such as antibiotics, and more. Other lifestyle traits, such as sleep deprivation, stress, various environmental exposures and occupation, have also been correlated with the composition of the microbiota. Understanding the relationships between humans and the microorganisms that line our guts is therefore critical to the understanding of health and disease.

How The Gut Microbiome Affects Metabolic Health

To live in a peaceful partnership, the gut microbiome is in constant communication with our body. This communication occurs via several small messenger molecules, called metabolites. Changes in the concentrations of these messengers can communicate situations of health, disease, and stress.

The human microbiome produces several metabolites important for host-microbe interactions, such as bile acids, Short-Chain Fatty Acids (SCFAs), ammonia, phenols, and endotoxins, among other compounds. These metabolites are essential for maintaining host physiology and also provide insights into the impact of lifestyle and dietary factors on diseases.

SCFAs are amongst the main metabolites produced by the gut and have garnered considerable interest in their role in human health and disease. According to a paper published in Beneficial Microbes in 2020 evidence is accumulating that SCFAs play an important role in the maintenance of gut and metabolic health.

More specifically, SCFAs such as acetate, propionate, and butyrate are produced when the bacteria in our gut ferment otherwise indigestible dietary fiber and starch in the gut. These SCFAs are essential in maintaining gut integrity through the regulation of pH, mucus production, and more. They also directly modulate a variety of metabolic functions including appetite regulation, energy expenditure, glucose homeostasis, and immunomodulation.

Studies in humans have suggested that people with obesity and diabetes have fewer bacteria that produce the SCFA butyrate. These studies suggest a link between the importance of butyrate and metabolic conditions. A study in mice suggests that butyrate improves insulin sensitivity and increases energy expenditure - further highlighting that butyrate levels may be linked to conditions such as obesity and diabetes.

Many other animal studies have suggested that SCFAs play an important role in the prevention and treatment of obesity-associated insulin resistance. Similar research in humans is currently limited but promising. SCFAs such as propionate and butyrate have the ability to affect energy intake and the secretion of insulin via the production of satiety hormones.

Interestingly, the limited studies in humans show that rectal infusions of SCFA mixtures increased the circulated concentration of appetite regulators in individuals who were overweight. These studies suggest that SCFA and it’s receptors may be potential targets for the treatment of metabolic diseases such as obesity and diabetes.

Caring For Your Gut Microbiome

As you have probably gathered by now, a healthy gut microbiome is important for health. The balance of the gut microbiome can be affected by a number of factors, which lead to infection. Maintaining the gut microbiome, therefore, can prevent a number of health conditions including metabolic health conditions such as diabetes.

For this reason, anything that helps “feed” the good gut microbiome is good for overall health. There are various ways in which you can keep the good bacteria happy. This includes not overusing antibiotics, where possible, as these drugs kill good and bad bacteria. After you complete antibiotic treatment, it is also recommended that you take probiotics to replace/restore microbes lost during antibiotic treatment.

Another way to feed and replenish the good bacteria is to eat fermented foods and foods high in fiber. Fermented foods include yogurt, cheese, kombucha, kimchi, and others. Foods high in fiber include whole grains, nuts, seeds, beans, green vegetables such as broccoli, and lentils. These foods can help facilitate the growth of the gut microbiota after damage caused by antibiotics or other changes in lifestyle.

You can also feed the gut microbiota food that facilitates their growth i.e. by taking prebiotics. Taking prebiotics is an excellent way to ensure that the good bacteria in your body are encouraged to grow. They also help in the restoration of the gut microbiota after you complete your course of antibiotics.

Several good studies* suggest that manipulation of the gut microbiota through the administration of prebiotics and probiotics (alongside lifestyle changes) may help with reducing the risks of various metabolic health conditions such as insulin resistance and obesity, and other conditions, including predisposition to immune dysfnction and even cancer **

References

*Probiotics and prebiotics in intestinal health and disease: from biology to the clinic. Sanders ME, Merenstein DJ, Reid G, Gibson GR, Rastall RA.Nat Rev Gastroenterol Hepatol. 2019 Oct;16(10):605-616. doi: 10.1038/s41575-019-0173-3

** The impact of probiotics and prebiotics on the immune system.Klaenhammer TR, Kleerebezem M, Kopp MV, Rescigno M.Nat Rev Immunol. 2012 Oct;12(10):728-34. doi: 10.1038/nri3312.  

Manipulating the gut microbiota to maintain health and treat disease.Scott KP, Antoine JM, Midtvedt T, van Hemert S.Microb Ecol Health Dis. 2015 Feb 2;26:25877. doi: 10.3402/mehd.v26.25877

Gut microbiota modulation: a novel strategy for prevention and treatment of colorectal cancer.Fong W, Li Q, Yu J.Oncogene. 2020 Jun;39(26):4925-4943. doi: 10.1038/s41388-020-1341-1


The human gut microbiome refers to the collection of microorganisms that resides in the gastrointestinal tract. About 100 trillion microorganisms, including both good and bad bacteria, line our gut and play a crucial role in the body. These microorganisms may protect from diseases but sometimes bacteria could predispose to a number of conditions, including but not limited to, obesity, type 2 diabetes, hypertension, colorectal cancer, and inflammatory bowel disease.

Why Do We Have A Gut Microbiome?

Our gut microbiome plays many crucial roles in our body. For example, the “good” bacteria act like our partners and play a central role in the breakdown and synthesis of nutrients, ensuring they are available to the body for absorption. The gut bacteria also play a vital role in immunity -- protecting our gut from “bad” bacteria and also promoting the integrity of the lining of the gut.

Mice that are grown in the laboratory in the absence of their gut bacteria show metabolic and immunological impairments, further demonstrating the importance of the trillions of occupiers of our body. These bacteria are so important to humans, that some researchers believe that a developing fetus in the mother’s womb is exposed to these bacteria via the placenta.

Throughout adulthood, the gut microbiome continues to grow and flourish. For this reason, a variety of factors can influence the composition of the gut microbiome. These factors include host genetics, immune responses, antibiotic usage, lifestyle, circadian rhythms, and the environment. Due to the intimate relationship between the microbiome and our body, any variations in the microbiota can cause harm to our body and lead to a myriad of diseases.

Throughout our lives, the gut microbiome may be harmed by low-fiber diets, high-sugar diets, medication such as antibiotics, and more. Other lifestyle traits, such as sleep deprivation, stress, various environmental exposures and occupation, have also been correlated with the composition of the microbiota. Understanding the relationships between humans and the microorganisms that line our guts is therefore critical to the understanding of health and disease.

How The Gut Microbiome Affects Metabolic Health

To live in a peaceful partnership, the gut microbiome is in constant communication with our body. This communication occurs via several small messenger molecules, called metabolites. Changes in the concentrations of these messengers can communicate situations of health, disease, and stress.

The human microbiome produces several metabolites important for host-microbe interactions, such as bile acids, Short-Chain Fatty Acids (SCFAs), ammonia, phenols, and endotoxins, among other compounds. These metabolites are essential for maintaining host physiology and also provide insights into the impact of lifestyle and dietary factors on diseases.

SCFAs are amongst the main metabolites produced by the gut and have garnered considerable interest in their role in human health and disease. According to a paper published in Beneficial Microbes in 2020 evidence is accumulating that SCFAs play an important role in the maintenance of gut and metabolic health.

More specifically, SCFAs such as acetate, propionate, and butyrate are produced when the bacteria in our gut ferment otherwise indigestible dietary fiber and starch in the gut. These SCFAs are essential in maintaining gut integrity through the regulation of pH, mucus production, and more. They also directly modulate a variety of metabolic functions including appetite regulation, energy expenditure, glucose homeostasis, and immunomodulation.

Studies in humans have suggested that people with obesity and diabetes have fewer bacteria that produce the SCFA butyrate. These studies suggest a link between the importance of butyrate and metabolic conditions. A study in mice suggests that butyrate improves insulin sensitivity and increases energy expenditure - further highlighting that butyrate levels may be linked to conditions such as obesity and diabetes.

Many other animal studies have suggested that SCFAs play an important role in the prevention and treatment of obesity-associated insulin resistance. Similar research in humans is currently limited but promising. SCFAs such as propionate and butyrate have the ability to affect energy intake and the secretion of insulin via the production of satiety hormones.

Interestingly, the limited studies in humans show that rectal infusions of SCFA mixtures increased the circulated concentration of appetite regulators in individuals who were overweight. These studies suggest that SCFA and it’s receptors may be potential targets for the treatment of metabolic diseases such as obesity and diabetes.

Caring For Your Gut Microbiome

As you have probably gathered by now, a healthy gut microbiome is important for health. The balance of the gut microbiome can be affected by a number of factors, which lead to infection. Maintaining the gut microbiome, therefore, can prevent a number of health conditions including metabolic health conditions such as diabetes.

For this reason, anything that helps “feed” the good gut microbiome is good for overall health. There are various ways in which you can keep the good bacteria happy. This includes not overusing antibiotics, where possible, as these drugs kill good and bad bacteria. After you complete antibiotic treatment, it is also recommended that you take probiotics to replace/restore microbes lost during antibiotic treatment.

Another way to feed and replenish the good bacteria is to eat fermented foods and foods high in fiber. Fermented foods include yogurt, cheese, kombucha, kimchi, and others. Foods high in fiber include whole grains, nuts, seeds, beans, green vegetables such as broccoli, and lentils. These foods can help facilitate the growth of the gut microbiota after damage caused by antibiotics or other changes in lifestyle.

You can also feed the gut microbiota food that facilitates their growth i.e. by taking prebiotics. Taking prebiotics is an excellent way to ensure that the good bacteria in your body are encouraged to grow. They also help in the restoration of the gut microbiota after you complete your course of antibiotics.

Several good studies* suggest that manipulation of the gut microbiota through the administration of prebiotics and probiotics (alongside lifestyle changes) may help with reducing the risks of various metabolic health conditions such as insulin resistance and obesity, and other conditions, including predisposition to immune dysfnction and even cancer **

References

*Probiotics and prebiotics in intestinal health and disease: from biology to the clinic. Sanders ME, Merenstein DJ, Reid G, Gibson GR, Rastall RA.Nat Rev Gastroenterol Hepatol. 2019 Oct;16(10):605-616. doi: 10.1038/s41575-019-0173-3

** The impact of probiotics and prebiotics on the immune system.Klaenhammer TR, Kleerebezem M, Kopp MV, Rescigno M.Nat Rev Immunol. 2012 Oct;12(10):728-34. doi: 10.1038/nri3312.  

Manipulating the gut microbiota to maintain health and treat disease.Scott KP, Antoine JM, Midtvedt T, van Hemert S.Microb Ecol Health Dis. 2015 Feb 2;26:25877. doi: 10.3402/mehd.v26.25877

Gut microbiota modulation: a novel strategy for prevention and treatment of colorectal cancer.Fong W, Li Q, Yu J.Oncogene. 2020 Jun;39(26):4925-4943. doi: 10.1038/s41388-020-1341-1