‘Gut bacteria picky about what we eat’
One type prefers high-fat:
Another prefers high-fibre feast:
US: Gut bacteria colonies of bacteria that live in the human
digestive tract appear to have fairly picky dining habits, with one type
preferring high-fat, fast-food fare, and another preferring a high-fiber
feast, U.S. researchers said on Thursday.
Researchers are increasingly trying to understand the interplay of
bacteria and their human hosts.
“We know our human bodies are colonized with tons and tons of
bacteria and other organisms. In your colon alone, you have more
bacterial cells than you have human cells in your whole body,” said Dr.
James Lewis, a researcher at the the University of Pennsylvania, who
worked on the study published in the journal Science.
Last April, German researchers reported that gut bacteria fall into
three distinct types. Lewis’ team wanted to see how these different
types of gut bacteria affect human health.
“The unique feature of the intestines is that they are constantly
bathed in what we eat. It seemed logical to us that some of the
differences between one person’s gut bacteria and another could be
related to what they eat,” Lewis said in a telephone interview.
To understand that, the team had to sort through a lot of excrement.
“We fondly refer to this as the poop study,” Lewis said.
For the first part of the study, the team recruited 98 healthy
volunteers and collected stool samples from each. The volunteers also
filled out a detailed questionnaire of their eating habits.
Then the researchers used high-tech gene sequencing machines to
determine the genetic code of the bacteria living in the volunteers’
colons.
They found that the gut bacteria were largely from two distinct
groups or enterotypes one called Bacteroides that preferred a typical
Western diet rich in meat and fat, and another called Prevotella that
preferred a high-carbohydrate diet.
Next, the team wanted to see if they could alter the gut bacteria by
changing people’s diets.
They recruited 10 healthy people who checked into a hospital for a
10-day controlled eating study. Half of the group ate a high-fat,
low-fiber diet, and the other ate a low-fat, high-fiber diet.
Within 24 hours, the team saw changes in the composition of the gut
bacteria but the overall enterotype remained the same.
Lewis said the findings suggest bacteria that live in the gut are
sensitive to short term changes in diet, but it may take a long-term
dietary change to significantly alter the types of bacteria that reside
in the gut. Reuters |