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WASHINGTON – – including amino acid metabolites – that may modify health, said Gary D. Wu, MD, of the University of Pennsylvania, Philadelphia.
During the 2022 Gut Microbiota for Health World Summit, organized by the American Gastroenterological Association and the European Society of Neurogastroenterology and Motility, Dr. Wu led a plenary session in which the impact of diet on the microbiome was characterized as important, rapid, personalized, likely modest relative to other contributing ecological factors, influenced by the process of cooking, and exceedingly difficult to tease apart and characterize in human studies.
In a human study published in 2021, Dr. Wu and coinvestigators performed a controlled feeding experiment with 30 healthy volunteers, randomizing them to several weeks of a vegan diet, an omnivore diet (a typical American diet), and an exclusive enteral nutrition diet (EEN) devoid of dietary fiber.
They compared the composition and metabolic function of the gut microbiome during three phases: an initial dietary phase (days 1-5), a purge phase in which antibiotics and polyethylene glycol were administered to transiently reduce bacterial load in the gut (days 6-8), and a recovery phase (days 9-15).
Diversity of the gut microbiota recovered from the purge phase in both vegans and omnivores, but not in those receiving EEN. “The EEN diet was having a profound effect on the [short-term] recovery of microbiota,” said Dr. Wu, the Ferdinand G. Weisbrod Professor in Gastroenterology, in describing the Food And Resulting Microbial Metabolites study.
Using genetic sequencing, microbial culturing, and bioinformatics processing, the researchers also determined that EEN subsequently led to metabolites that were distinct from omnivores and vegans. Unexpectedly, bacterial metabolites of amino acid origin – not only carbohydrate origin – were altered in the EEN group, suggesting a broad impact of dietary fiber on the bacterial metabolome. EEN-induced alterations in the microbiome and metabolome resolved after the study period, he noted.
In other words, “depriving or supplying the gut microbiome with one dietary component (i.e., fiber) can directly impact metabolites of an unrelated portion of the diet (i.e., amino acids) via the induction of specific gut bacterial taxa,” Dr. Wu and colleagues wrote.
Clinically, the results as a whole suggest that the combination of antibiotics with EEN may be less effective in patients with Crohn’s disease than EEN alone, and can be potentially harmful, they said.
At the meeting, sponsored by the American Gastroenterological Association and the European Society for Neurogastroenterology and Motility, Dr. Wu said that, for patients in the ICU on EEN treatment and antibiotics, “we do need to think carefully about microbiota reconstitution because it could have a very significant effect not only on short-chain fatty acid metabolites but on amino acid metabolites that may be good or bad in the setting of disease.”
The scientific rationale for the effectiveness of EEN for IBD is still not well understood, he noted. “All I can say is that EEN works in IBD, but there are aspects about the microbiota and diet and IBD that we don’t understand.”
Dietary impact through the immigration lens
In another presentation, Dan Knights, PhD, of the University of Minnesota, Minneapolis, described his lab’s findings on the association of U.S. immigration with loss of gut microbiome diversity, and the role of diet.
As part of the Immigration Microbiome Project reported several years ago, his team collected stool, dietary recalls, and anthropometrics from 550 Hmong and Karen individuals living in Thailand and the United States, including first- and second-generation immigrants, as well as some U.S.-born European American individuals. They found that the gut microbiome of immigrants changed within months of arriving in the United States, and that immigration status had a stronger effect on the microbiome than obesity status.
“By the time people were in their second generation, their microbiomes were roughly on the same order of diversity as U.S. controls,” said Dr. Knights, associate professor in the Biotechnology Institute and the department of computer science and engineering.
Dietary changes only partly explained microbiome variation, however. “By the second generation, the microbiome tended to be fully Westernized, but the diet was only partly Westernized,” he said. “Diet is only part of the story.”
Other research from his lab, including one study that performed daily fecal shotgun sequencing on 34 people, has found that effects of diet on the microbiome are likely to be observable within days, and that microbial responses to food are highly personalized. Diet appears to explain about 6% of the daily microbiome variation within an individual, and “an average diet explains about 4% of microbiome variation between people,” Dr. Knights said.
The impact of cooking
“The gut microbiota responds to food and to its form,” said Rachel N. Carmody, PhD, of the department of human evolutionary biology at Harvard University, Cambridge, during the plenary session. Her research has shown that, in mice, a plant diet served raw versus cooked quickly reshaped the gut microbiome and disrupted gut microbial physiology. Notably, shifts in gut microbiota modulated host energy status – one of the many areas that begs further research.
The effects of cooking have also been detectable in human pilot studies. “We saw different changes in the microbiome when [study participants] were eating the same plant items either raw or cooked,” she said. “Some microbes were affected only on the raw diet, other were affected only on the cooked diet.”
Other research in animal models and humans has demonstrated a significant amount of plasticity in the microbiome in response to diet. “In mice you get the microbiome signatures to shift within 24 hours by feeding them a new diet,” Dr. Carmody said.
In an interview about the plenary session, Eugene B. Chang, MD, the Martin Boyer Distinguished Professor of Medicine at the University of Chicago, said that he was struck both by the resiliency of individual gut microbiomes overall and by findings that, “in animal models where conditions and diets can be carefully controlled, diet and environment are major drivers of gut microbial membership and function.”
Dr. Chang co-led a separate workshop on “defining a healthy gut microbiome” – a task that he said remains “a challenge [and is not yet] resolved, at least with general consensus.”
Dr. Chang, Dr. Wu, and Dr. Carmody reported no relevant disclosures. Dr. Knights disclosed that he is a paid adviser to Diversigen, a company involved with the commercialization of microbiome analysis.
The 2022 Gut Microbiota for Health World Summit was supported by sponsorships from Danone, Ferring Pharmaceuticals, Aimmune Therapeutics and Seres Therapeutics, Sanofi, and Intrinsic Medicine Inc. with additional support from educational grants provided by Ferring Pharmaceuticals and Salix Pharmaceuticals.
This article was updated 4/5/22.
WASHINGTON – – including amino acid metabolites – that may modify health, said Gary D. Wu, MD, of the University of Pennsylvania, Philadelphia.
During the 2022 Gut Microbiota for Health World Summit, organized by the American Gastroenterological Association and the European Society of Neurogastroenterology and Motility, Dr. Wu led a plenary session in which the impact of diet on the microbiome was characterized as important, rapid, personalized, likely modest relative to other contributing ecological factors, influenced by the process of cooking, and exceedingly difficult to tease apart and characterize in human studies.
In a human study published in 2021, Dr. Wu and coinvestigators performed a controlled feeding experiment with 30 healthy volunteers, randomizing them to several weeks of a vegan diet, an omnivore diet (a typical American diet), and an exclusive enteral nutrition diet (EEN) devoid of dietary fiber.
They compared the composition and metabolic function of the gut microbiome during three phases: an initial dietary phase (days 1-5), a purge phase in which antibiotics and polyethylene glycol were administered to transiently reduce bacterial load in the gut (days 6-8), and a recovery phase (days 9-15).
Diversity of the gut microbiota recovered from the purge phase in both vegans and omnivores, but not in those receiving EEN. “The EEN diet was having a profound effect on the [short-term] recovery of microbiota,” said Dr. Wu, the Ferdinand G. Weisbrod Professor in Gastroenterology, in describing the Food And Resulting Microbial Metabolites study.
Using genetic sequencing, microbial culturing, and bioinformatics processing, the researchers also determined that EEN subsequently led to metabolites that were distinct from omnivores and vegans. Unexpectedly, bacterial metabolites of amino acid origin – not only carbohydrate origin – were altered in the EEN group, suggesting a broad impact of dietary fiber on the bacterial metabolome. EEN-induced alterations in the microbiome and metabolome resolved after the study period, he noted.
In other words, “depriving or supplying the gut microbiome with one dietary component (i.e., fiber) can directly impact metabolites of an unrelated portion of the diet (i.e., amino acids) via the induction of specific gut bacterial taxa,” Dr. Wu and colleagues wrote.
Clinically, the results as a whole suggest that the combination of antibiotics with EEN may be less effective in patients with Crohn’s disease than EEN alone, and can be potentially harmful, they said.
At the meeting, sponsored by the American Gastroenterological Association and the European Society for Neurogastroenterology and Motility, Dr. Wu said that, for patients in the ICU on EEN treatment and antibiotics, “we do need to think carefully about microbiota reconstitution because it could have a very significant effect not only on short-chain fatty acid metabolites but on amino acid metabolites that may be good or bad in the setting of disease.”
The scientific rationale for the effectiveness of EEN for IBD is still not well understood, he noted. “All I can say is that EEN works in IBD, but there are aspects about the microbiota and diet and IBD that we don’t understand.”
Dietary impact through the immigration lens
In another presentation, Dan Knights, PhD, of the University of Minnesota, Minneapolis, described his lab’s findings on the association of U.S. immigration with loss of gut microbiome diversity, and the role of diet.
As part of the Immigration Microbiome Project reported several years ago, his team collected stool, dietary recalls, and anthropometrics from 550 Hmong and Karen individuals living in Thailand and the United States, including first- and second-generation immigrants, as well as some U.S.-born European American individuals. They found that the gut microbiome of immigrants changed within months of arriving in the United States, and that immigration status had a stronger effect on the microbiome than obesity status.
“By the time people were in their second generation, their microbiomes were roughly on the same order of diversity as U.S. controls,” said Dr. Knights, associate professor in the Biotechnology Institute and the department of computer science and engineering.
Dietary changes only partly explained microbiome variation, however. “By the second generation, the microbiome tended to be fully Westernized, but the diet was only partly Westernized,” he said. “Diet is only part of the story.”
Other research from his lab, including one study that performed daily fecal shotgun sequencing on 34 people, has found that effects of diet on the microbiome are likely to be observable within days, and that microbial responses to food are highly personalized. Diet appears to explain about 6% of the daily microbiome variation within an individual, and “an average diet explains about 4% of microbiome variation between people,” Dr. Knights said.
The impact of cooking
“The gut microbiota responds to food and to its form,” said Rachel N. Carmody, PhD, of the department of human evolutionary biology at Harvard University, Cambridge, during the plenary session. Her research has shown that, in mice, a plant diet served raw versus cooked quickly reshaped the gut microbiome and disrupted gut microbial physiology. Notably, shifts in gut microbiota modulated host energy status – one of the many areas that begs further research.
The effects of cooking have also been detectable in human pilot studies. “We saw different changes in the microbiome when [study participants] were eating the same plant items either raw or cooked,” she said. “Some microbes were affected only on the raw diet, other were affected only on the cooked diet.”
Other research in animal models and humans has demonstrated a significant amount of plasticity in the microbiome in response to diet. “In mice you get the microbiome signatures to shift within 24 hours by feeding them a new diet,” Dr. Carmody said.
In an interview about the plenary session, Eugene B. Chang, MD, the Martin Boyer Distinguished Professor of Medicine at the University of Chicago, said that he was struck both by the resiliency of individual gut microbiomes overall and by findings that, “in animal models where conditions and diets can be carefully controlled, diet and environment are major drivers of gut microbial membership and function.”
Dr. Chang co-led a separate workshop on “defining a healthy gut microbiome” – a task that he said remains “a challenge [and is not yet] resolved, at least with general consensus.”
Dr. Chang, Dr. Wu, and Dr. Carmody reported no relevant disclosures. Dr. Knights disclosed that he is a paid adviser to Diversigen, a company involved with the commercialization of microbiome analysis.
The 2022 Gut Microbiota for Health World Summit was supported by sponsorships from Danone, Ferring Pharmaceuticals, Aimmune Therapeutics and Seres Therapeutics, Sanofi, and Intrinsic Medicine Inc. with additional support from educational grants provided by Ferring Pharmaceuticals and Salix Pharmaceuticals.
This article was updated 4/5/22.
WASHINGTON – – including amino acid metabolites – that may modify health, said Gary D. Wu, MD, of the University of Pennsylvania, Philadelphia.
During the 2022 Gut Microbiota for Health World Summit, organized by the American Gastroenterological Association and the European Society of Neurogastroenterology and Motility, Dr. Wu led a plenary session in which the impact of diet on the microbiome was characterized as important, rapid, personalized, likely modest relative to other contributing ecological factors, influenced by the process of cooking, and exceedingly difficult to tease apart and characterize in human studies.
In a human study published in 2021, Dr. Wu and coinvestigators performed a controlled feeding experiment with 30 healthy volunteers, randomizing them to several weeks of a vegan diet, an omnivore diet (a typical American diet), and an exclusive enteral nutrition diet (EEN) devoid of dietary fiber.
They compared the composition and metabolic function of the gut microbiome during three phases: an initial dietary phase (days 1-5), a purge phase in which antibiotics and polyethylene glycol were administered to transiently reduce bacterial load in the gut (days 6-8), and a recovery phase (days 9-15).
Diversity of the gut microbiota recovered from the purge phase in both vegans and omnivores, but not in those receiving EEN. “The EEN diet was having a profound effect on the [short-term] recovery of microbiota,” said Dr. Wu, the Ferdinand G. Weisbrod Professor in Gastroenterology, in describing the Food And Resulting Microbial Metabolites study.
Using genetic sequencing, microbial culturing, and bioinformatics processing, the researchers also determined that EEN subsequently led to metabolites that were distinct from omnivores and vegans. Unexpectedly, bacterial metabolites of amino acid origin – not only carbohydrate origin – were altered in the EEN group, suggesting a broad impact of dietary fiber on the bacterial metabolome. EEN-induced alterations in the microbiome and metabolome resolved after the study period, he noted.
In other words, “depriving or supplying the gut microbiome with one dietary component (i.e., fiber) can directly impact metabolites of an unrelated portion of the diet (i.e., amino acids) via the induction of specific gut bacterial taxa,” Dr. Wu and colleagues wrote.
Clinically, the results as a whole suggest that the combination of antibiotics with EEN may be less effective in patients with Crohn’s disease than EEN alone, and can be potentially harmful, they said.
At the meeting, sponsored by the American Gastroenterological Association and the European Society for Neurogastroenterology and Motility, Dr. Wu said that, for patients in the ICU on EEN treatment and antibiotics, “we do need to think carefully about microbiota reconstitution because it could have a very significant effect not only on short-chain fatty acid metabolites but on amino acid metabolites that may be good or bad in the setting of disease.”
The scientific rationale for the effectiveness of EEN for IBD is still not well understood, he noted. “All I can say is that EEN works in IBD, but there are aspects about the microbiota and diet and IBD that we don’t understand.”
Dietary impact through the immigration lens
In another presentation, Dan Knights, PhD, of the University of Minnesota, Minneapolis, described his lab’s findings on the association of U.S. immigration with loss of gut microbiome diversity, and the role of diet.
As part of the Immigration Microbiome Project reported several years ago, his team collected stool, dietary recalls, and anthropometrics from 550 Hmong and Karen individuals living in Thailand and the United States, including first- and second-generation immigrants, as well as some U.S.-born European American individuals. They found that the gut microbiome of immigrants changed within months of arriving in the United States, and that immigration status had a stronger effect on the microbiome than obesity status.
“By the time people were in their second generation, their microbiomes were roughly on the same order of diversity as U.S. controls,” said Dr. Knights, associate professor in the Biotechnology Institute and the department of computer science and engineering.
Dietary changes only partly explained microbiome variation, however. “By the second generation, the microbiome tended to be fully Westernized, but the diet was only partly Westernized,” he said. “Diet is only part of the story.”
Other research from his lab, including one study that performed daily fecal shotgun sequencing on 34 people, has found that effects of diet on the microbiome are likely to be observable within days, and that microbial responses to food are highly personalized. Diet appears to explain about 6% of the daily microbiome variation within an individual, and “an average diet explains about 4% of microbiome variation between people,” Dr. Knights said.
The impact of cooking
“The gut microbiota responds to food and to its form,” said Rachel N. Carmody, PhD, of the department of human evolutionary biology at Harvard University, Cambridge, during the plenary session. Her research has shown that, in mice, a plant diet served raw versus cooked quickly reshaped the gut microbiome and disrupted gut microbial physiology. Notably, shifts in gut microbiota modulated host energy status – one of the many areas that begs further research.
The effects of cooking have also been detectable in human pilot studies. “We saw different changes in the microbiome when [study participants] were eating the same plant items either raw or cooked,” she said. “Some microbes were affected only on the raw diet, other were affected only on the cooked diet.”
Other research in animal models and humans has demonstrated a significant amount of plasticity in the microbiome in response to diet. “In mice you get the microbiome signatures to shift within 24 hours by feeding them a new diet,” Dr. Carmody said.
In an interview about the plenary session, Eugene B. Chang, MD, the Martin Boyer Distinguished Professor of Medicine at the University of Chicago, said that he was struck both by the resiliency of individual gut microbiomes overall and by findings that, “in animal models where conditions and diets can be carefully controlled, diet and environment are major drivers of gut microbial membership and function.”
Dr. Chang co-led a separate workshop on “defining a healthy gut microbiome” – a task that he said remains “a challenge [and is not yet] resolved, at least with general consensus.”
Dr. Chang, Dr. Wu, and Dr. Carmody reported no relevant disclosures. Dr. Knights disclosed that he is a paid adviser to Diversigen, a company involved with the commercialization of microbiome analysis.
The 2022 Gut Microbiota for Health World Summit was supported by sponsorships from Danone, Ferring Pharmaceuticals, Aimmune Therapeutics and Seres Therapeutics, Sanofi, and Intrinsic Medicine Inc. with additional support from educational grants provided by Ferring Pharmaceuticals and Salix Pharmaceuticals.
This article was updated 4/5/22.
AT GMFH 2022