Efficient Gut Bacteria Linked to Obesity/Weight Gain ?

Washington University researchers, in two recent papers in the journal
"Nature" put forward evidence of a statistical link between efficient
gut bacteria and weight gain. One study was in mice, another in humans.

Not everyone agrees that the statistical correlation is cause and effect.

Two versions of published writeups of these studies are below. Just
extracts are given here......


-----------------------
New Scientist Magazine
http://www.newscientist.com/article/...ur-weight.html

The amount of weight an animal gains from eating depends partly on the
types of microbes found in its gut, a new mouse study reveals.

Mice with microbes that are better at extracting energy from food end up
fatter, researchers say. And when obese people diet, they lose some of
these fattening microbes from their guts, according to a related report.

snip
Compared with Bacteroidetes bacteria, Firmicutes bacteria might have a
wider range of enzymes for breaking down complex carbohydrates, the
researchers say. This could make them more efficient at extracting
energy from food, which our bodies ultimately convert into fat.

"Striking result"

In a related study, Gordon’s team determined the microbial makeup of 12
obese people by conducting a genetic analysis of their faeces. This
revealed that these individuals had a higher ratio of Firmicutes to
Bacteroidetes bugs than lean people involved in the study. For example,
Bacteroidetes microbes constituted 5% of the obese people’s gut flora,
but 20% of the lean subjects’.

After a year of either a carbohydrate- or fat-restricted diet, the obese
individuals lost weight and the ratio of Firmicutes to Bacteroidetes
bugs shifted towards that of their lean counterparts. In the end,
Bacteroidetes made up about 15% of their gut flora.

“It’s a striking result and it’s constant across all of these different
people,” comments David Relman at Stanford University in California, US,
who did an earlier, landmark genetic analysis of human gut bugs
(Science, vol 308, p 1635). “It’s not just having microbes, it’s the
particular makeup that might matter,” he adds.

Journal: Nature (DOI: 10.1038/nature4441022a) and (DOI: 10.1038/nature05414)

---------------------------------

Los Angeles Times
http://www.latimes.com/news/nationwo...adlines-nation

Experts cautioned that it was too soon to manipulate gut bacteria in the
hopes of becoming slimmer.

The proliferation of the efficient bacteria may be the result of obesity
and not its cause, said Dr. Richard Atkinson of the Obetech Obesity
Research Center in Richmond, Va., who was not involved in the research.

"If they are right, this could really be a significant advance," he
said. "But I am not sure they are interpreting their data right.
Correlation is not causation."

Neurobiologist Hans-Rudolf Berthoud of Louisiana State University's
Pennington Biomedical Research Center in Baton Rouge, who was not
involved in the research, agreed.

"This doesn't show that the bacteria cause obesity, absolutely not," he
said.

More likely, he said, is that hormonal changes in the gut caused by
weight loss alter the distribution of bacteria.

Atkinson questioned whether the small difference in efficiency between
the two types of bacteria was sufficient to explain weight gain.

Gordon thinks they are.

"The differences don't have to be great, but over the course of a year,
the effects can add up," he said.

The two studies were funded by the National Institutes of Health and the
W.M. Keck Foundation.




--
1) Eat Till SATISFIED, Not STUFFED... Atkins repeated 9 times in the book
2) Exercise: It's Non-Negotiable..... Chapter 22 title, Atkins book
3) Don't Diet Without Supplemental Nutrients... Chapter 23 title, Atkins
book
4) A sensible eating plan, and follow it. (Atkins, Self Made or Other)

Jbuch wrote:
Washington University researchers, in two recent papers in the journal
"Nature" put forward evidence of a statistical link between efficient
gut bacteria and weight gain. One study was in mice, another in humans.

Not everyone agrees that the statistical correlation is cause and effect.

Two versions of published writeups of these studies are below. Just
extracts are given here......


-----------------------
New Scientist Magazine
http://www.newscientist.com/article/...ur-weight.html

The amount of weight an animal gains from eating depends partly on the
types of microbes found in its gut, a new mouse study reveals.

Mice with microbes that are better at extracting energy from food end up
fatter, researchers say. And when obese people diet, they lose some of
these fattening microbes from their guts, according to a related report.

snip
Compared with Bacteroidetes bacteria, Firmicutes bacteria might have a
wider range of enzymes for breaking down complex carbohydrates, the
researchers say. This could make them more efficient at extracting
energy from food, which our bodies ultimately convert into fat.

"Striking result"

In a related study, Gordon's team determined the microbial makeup of 12
obese people by conducting a genetic analysis of their faeces. This
revealed that these individuals had a higher ratio of Firmicutes to
Bacteroidetes bugs than lean people involved in the study. For example,
Bacteroidetes microbes constituted 5% of the obese people's gut flora,
but 20% of the lean subjects'.

After a year of either a carbohydrate- or fat-restricted diet, the obese
individuals lost weight and the ratio of Firmicutes to Bacteroidetes
bugs shifted towards that of their lean counterparts. In the end,
Bacteroidetes made up about 15% of their gut flora.

"It's a striking result and it's constant across all of these different
people," comments David Relman at Stanford University in California, US,
who did an earlier, landmark genetic analysis of human gut bugs
(Science, vol 308, p 1635). "It's not just having microbes, it's the
particular makeup that might matter," he adds.

Journal: Nature (DOI: 10.1038/nature4441022a) and (DOI: 10.1038/nature05414)

---------------------------------

Los Angeles Times
http://www.latimes.com/news/nationwo...adlines-nation

Experts cautioned that it was too soon to manipulate gut bacteria in the
hopes of becoming slimmer.

The proliferation of the efficient bacteria may be the result of obesity
and not its cause, said Dr. Richard Atkinson of the Obetech Obesity
Research Center in Richmond, Va., who was not involved in the research.

"If they are right, this could really be a significant advance," he
said. "But I am not sure they are interpreting their data right.
Correlation is not causation."

Neurobiologist Hans-Rudolf Berthoud of Louisiana State University's
Pennington Biomedical Research Center in Baton Rouge, who was not
involved in the research, agreed.

"This doesn't show that the bacteria cause obesity, absolutely not," he
said.

More likely, he said, is that hormonal changes in the gut caused by
weight loss alter the distribution of bacteria.

Atkinson questioned whether the small difference in efficiency between
the two types of bacteria was sufficient to explain weight gain.

Gordon thinks they are.

"The differences don't have to be great, but over the course of a year,
the effects can add up," he said.

The two studies were funded by the National Institutes of Health and the
W.M. Keck Foundation.




--
1) Eat Till SATISFIED, Not STUFFED... Atkins repeated 9 times in the book
2) Exercise: It's Non-Negotiable..... Chapter 22 title, Atkins book
3) Don't Diet Without Supplemental Nutrients... Chapter 23 title, Atkins
book
4) A sensible eating plan, and follow it. (Atkins, Self Made or Other)



Interesting. but as stated above, whether there is actual cause and
effect hasn't been proven. Also, never really thought about this
before, but it raises an obvious question. If bacteria are critical to
digestion and metabolism of nutrients, what happens when people take
broad spectrum antibiotics which kill most bacteria?

wrote in message
ps.com...


Interesting. but as stated above, whether there is actual cause and
effect hasn't been proven. Also, never really thought about this
before, but it raises an obvious question. If bacteria are critical to
digestion and metabolism of nutrients, what happens when people take
broad spectrum antibiotics which kill most bacteria?


Look up C. Diff , or Herxheimer Reactions.

Looking at the wikipedia entry for it the label of pseudoscience comes
to mind as this is said to be part of the highly questionable "detox"
scool of nonsense.

"Interesting. but as stated above, whether there is actual cause and
effect hasn't been proven. Also, never really thought about this
before, but it raises an obvious question. If bacteria are critical to
digestion and metabolism of nutrients, what happens when people take
broad spectrum antibiotics which kill most bacteria?"

The bacteria are those in the large gut. They play little or no role
for the major part of digestion in the small gut. They break down food
substances which aren't digested in the small gut and free the calories
for human absorption where otherwise it will just be passed.
Antibiotics disrupt the large gut bacteria and cause gi problems
sometimes but don't otherwise disturb normal digestion in the small gut.
Almost all digestion occurs in the small gut.

What is perhaps more important to the question of the role of ratios of
bacteria and different nutrients in ones diet,ie. low this or that
eaten. They tested different diets in humans to see if it made a
difference. Low carb or low fat diets produced the same results. As
people lost weight the ratio between the two types of bacteria changed
regardless.

The principle at work here is that one of the types found in fat people
are more efficient in converting more calories in the large gut from
otherwise undigestable food products. Even though the difference is
small over a year extra calories each day adds up to weight gain.

The real question is why the change occurs relatie to weight loss.
Rodents without bacteria fed either the "fat" or "lean" bacteria were
fat or normal in weight accordingly which suggests some active process
at work.

We hear of people who have problems losing weight even when reducing
calories, this in part could account for that. If the "lean" bacteria
could be caused to increase in ratio and maintained at the higher level
in fat people weight loss might occur over time because of the reduced
conversion of calories absorbed in the large gut as they also reduced
calorie intake otherwise.

wrote in message
u.edu...
Looking at the wikipedia entry for it the label of pseudoscience comes
to mind as this is said to be part of the highly questionable "detox"
scool of nonsense.

C. Diff is a myth? Many hospitals and nursing homes will be happy to hear
this.

Diet determines the nature of the gut flora. Treating the flora without
changing the diet is useless. A high grain diet will screw up your gut
flora and your health. Change the diet to more healthy foods and your
health and gut flora will change accordingly.

TC

Jbuch wrote:
Washington University researchers, in two recent papers in the journal
"Nature" put forward evidence of a statistical link between efficient
gut bacteria and weight gain. One study was in mice, another in humans.

Not everyone agrees that the statistical correlation is cause and effect.

Two versions of published writeups of these studies are below. Just
extracts are given here......


-----------------------
New Scientist Magazine
http://www.newscientist.com/article/...ur-weight.html

The amount of weight an animal gains from eating depends partly on the
types of microbes found in its gut, a new mouse study reveals.

Mice with microbes that are better at extracting energy from food end up
fatter, researchers say. And when obese people diet, they lose some of
these fattening microbes from their guts, according to a related report.

snip
Compared with Bacteroidetes bacteria, Firmicutes bacteria might have a
wider range of enzymes for breaking down complex carbohydrates, the
researchers say. This could make them more efficient at extracting
energy from food, which our bodies ultimately convert into fat.

"Striking result"

In a related study, Gordon's team determined the microbial makeup of 12
obese people by conducting a genetic analysis of their faeces. This
revealed that these individuals had a higher ratio of Firmicutes to
Bacteroidetes bugs than lean people involved in the study. For example,
Bacteroidetes microbes constituted 5% of the obese people's gut flora,
but 20% of the lean subjects'.

After a year of either a carbohydrate- or fat-restricted diet, the obese
individuals lost weight and the ratio of Firmicutes to Bacteroidetes
bugs shifted towards that of their lean counterparts. In the end,
Bacteroidetes made up about 15% of their gut flora.

"It's a striking result and it's constant across all of these different
people," comments David Relman at Stanford University in California, US,
who did an earlier, landmark genetic analysis of human gut bugs
(Science, vol 308, p 1635). "It's not just having microbes, it's the
particular makeup that might matter," he adds.

Journal: Nature (DOI: 10.1038/nature4441022a) and (DOI: 10.1038/nature05414)

---------------------------------

Los Angeles Times
http://www.latimes.com/news/nationwo...adlines-nation

Experts cautioned that it was too soon to manipulate gut bacteria in the
hopes of becoming slimmer.

The proliferation of the efficient bacteria may be the result of obesity
and not its cause, said Dr. Richard Atkinson of the Obetech Obesity
Research Center in Richmond, Va., who was not involved in the research.

"If they are right, this could really be a significant advance," he
said. "But I am not sure they are interpreting their data right.
Correlation is not causation."

Neurobiologist Hans-Rudolf Berthoud of Louisiana State University's
Pennington Biomedical Research Center in Baton Rouge, who was not
involved in the research, agreed.

"This doesn't show that the bacteria cause obesity, absolutely not," he
said.

More likely, he said, is that hormonal changes in the gut caused by
weight loss alter the distribution of bacteria.

Atkinson questioned whether the small difference in efficiency between
the two types of bacteria was sufficient to explain weight gain.

Gordon thinks they are.

"The differences don't have to be great, but over the course of a year,
the effects can add up," he said.

The two studies were funded by the National Institutes of Health and the
W.M. Keck Foundation.




--
1) Eat Till SATISFIED, Not STUFFED... Atkins repeated 9 times in the book
2) Exercise: It's Non-Negotiable..... Chapter 22 title, Atkins book
3) Don't Diet Without Supplemental Nutrients... Chapter 23 title, Atkins
book
4) A sensible eating plan, and follow it. (Atkins, Self Made or Other)

"Diet determines the nature of the gut flora. Treating the flora without
changing the diet is useless. A high grain diet will screw up your gut
flora and your health. Change the diet to more healthy foods and your
health and gut flora will change accordingly."

No, as mentioned here and even earlier to you specifically elsewhere, a
low carb or low fat diet made no difference in the human part of the
study.

The above is an example of what is becoming clear while reading
newsgroups. The more ignorant one is about the topic the more at
liberty to say just about anything about it while those who are informed
about it are constrained by knowing the reality of the science involved.
It is the flip side of "don't confuse me with the facts".

Looking at the wikipedia entry for it the label of pseudoscience comes
to mind as this is said to be part of the highly questionable "detox"
scool of nonsense.

" C. Diff is a myth? Many hospitals and nursing homes will be happy to
hear"

I used the other term you offered, "Herxheimer Reactions".

It is not a question of the reality of the two things but about the
reality of the explanation said to cause them. The Herxheimer Reactions
was said to be due to a "detox" program and the release of the "toxins"
from tissue in the system causing the symptoms. That is the
pseudoscience.