Probiotics May Help Stressed Gut
‘Good’ Bacteria Might Prevent Intestinal Problems From Chronic Stress
April 25, 2006 -- Gut-friendly bacteria called probiotics may help prevent
intestinal problems linked to chronic stress, a new study
The study appears in Gut's "online first" edition. The
researchers included Philip Sherman, MD, FRCP(C). Sherman works in the
gastroenterology and nutrition
division of Toronto's Hospital for Sick Children.
Sherman's team tested probiotics on rats, not people. Those tests showed
that probiotics seemed to thwart some intestinal problems linked to chronic
"Stress is a common experience of daily living," the researchers
write. The influence of stress on chronic intestinal disorders is "well
documented," they write, spotlighting irritable bowel syndrome and
inflammatory bowel diseases such as Crohn's
disease and ulcerative
However, the study doesn't make any recommendations about probiotic use in
Water Laced With Probiotics
First, the researchers assigned male rats into two groups, lacing the
drinking water of one group of rats with powder containing probiotics.
There are many types of probiotics. The probiotics powder used in Sherman's
study contained a strain of Lactobacillus rhamnosus and a strain of
For comparison, the other group of rats got sterile drinking water with no
Seven days later, the researchers put half of the rats in each group under
psychological stress. The point was to see if the rats that had been drinking
water containing probiotics had a different intestinal response to chronic
stress than rats that had been drinking sterile water without probiotics.
To create psychological (but not physical) stress in the rats, the
researchers put each rat on a platform in the middle of a plastic container
filled with warm water.
The platform stood 1 centimeter above the water. Rats don't like to swim, so
being on a little platform surrounded by water isn't their cup of tea.
The rest of the rats were placed on the same type of platform in an
identical container but without the water. That setting was designed to be much
less stressful for the rats.
The rats spent one hour a day for 10 days on their platforms. After that,
the researchers checked the rats' intestines.
All of the rats remained healthy during the study. "There were no signs
of diarrhea, weight
loss, or loss of appetite," the researchers write.
However, closer examination showed some subtle differences among the groups
of stressed rats.
Harmful bacteria latched onto cells in the intestinal wall and nearby lymph
nodes of stressed rats with sterile drinking water. But that wasn't true of
stressed rats that had been drinking probiotics-laced water.
Stressed rats that had gotten probiotics in their drinking water showed no
signs of harmful bacteria leaking to their lymph nodes. Probiotics -- not
harmful bacteria -- had attached to their intestinal walls.
2 Key Effects
Probiotics appeared to have two main actions in the rats, the researchers
- Probiotics may have successfully competed against harmful bacteria for a
spot on the rats' intestinal walls.
- Probiotics may also have helped maintain intestinal barriers, preventing
leakage of harmful bacteria.
The process behind those actions isn't clear, but probiotics may stick
better to intestinal walls than harmful bacteria, note Sherman and