The secret to successful aging may lie in part in your gut,
according to a new report. The study found that it may be possible to predict your
likelihood of living a long and healthy life by analyzing the trillions of
bacteria, viruses and fungi that inhabit your intestinal tract.
اضافة اعلان
The new research, published in the journal Nature Metabolism,
found that as people get older, the composition of this complex community of
microbes, collectively known as the gut microbiome, tends to change. And the
greater the change, the better, it appears.
In healthy people, the kinds of microbes that dominate the gut
in early adulthood make up a smaller and smaller proportion of the microbiome
over the ensuing decades, while the percentage of other, less prevalent species
rises. But in people who are less healthy, the study found, the opposite
occurs: The composition of their microbiomes remains relatively static and they
tend to die earlier.
The new findings suggest that a gut microbiome that continually
transforms as you get older is a sign of healthy aging, said a co-author of the
study, Sean Gibbons, a microbiome specialist and assistant professor at the
Institute for Systems Biology in Seattle, a nonprofit biomedical research
organization.
“A lot of aging research is obsessed with returning people to a
younger state or turning back the clock,” he said. “But here the conclusion is
very different. Maybe a microbiome that’s healthy for a 20-year-old is not at
all healthy for an 80-year-old. It seems that it’s good to have a changing
microbiome when you’re old. It means that the bugs that are in your system are
adjusting appropriately to an aging body.”
The researchers could not be certain whether changes in the gut
microbiome helped to drive healthy aging or vice versa. But they did see signs
that what happens in people’s guts may directly improve their health. They
found, for example, that people whose microbiomes shifted toward a unique
profile as they aged also had higher levels of health-promoting compounds in
their blood, including compounds produced by gut microbes that fight chronic
disease.
To get a better understanding of what happens in the gut as
people age, Gibbons and his colleagues, including Dr. Tomasz Wilmanski, the
lead author of the new study, looked at data on over 9,000 adults who had their
microbiomes sequenced. They ranged in age from 18 to 101.
About 900 of these people were seniors who underwent regular
checkups at medical clinics to assess their health. Gibbons and his colleagues
found that in midlife, starting at around age 40, people started to show
distinct changes in their microbiomes. The strains that were most dominant in
their guts tended to decline, while other, less common strains became more prevalent,
causing their microbiomes to diverge and look more and more different from
others in the population.
“What we found is that over the different decades of life,
individuals drift apart — their microbiomes become more and more unique from
one another,” said Gibbons.
People who had the most changes in their microbial compositions
tended to have better health and longer life spans. They had higher vitamin D
levels and lower levels of Low-Density Lipoprotein (LDL) cholesterol and
triglycerides, a type of fat in the blood. They needed fewer medications, and
they had better physical health, with faster walking speeds and greater
mobility.
The researchers speculated that some gut bugs that might be
innocuous or perhaps even beneficial in early adulthood could turn harmful in
old age. The study found, for example, that in healthy people who saw the most
dramatic shifts in their microbiome compositions there was a steep decline in
the prevalence of bacteria called Bacteroides, which are more common in
developed countries where people eat a lot of processed foods full of fat,
sugar and salt, and less prevalent in developing countries where people tend to
eat a higher-fiber diet. When fiber is not available, Gibbons said, Bacteroides
like to “munch on mucus,” including the protective mucus layer that lines the
gut.
“Maybe that’s good when you’re 20 or 30 and producing a lot of
mucus in your gut,” he said. “But as we get older, our mucus layer thins, and
maybe we may need to suppress these bugs.”
If those microbes chew through the barrier that keeps them
safely in the gut, it is possible they could trigger an immune system response.
“When that happens, the immune system goes nuts,” Gibbons said. “Having
that mucus layer is like having a barrier that maintains a détente that allows
us to live happily with our gut microbes, and if that goes away it starts a war”
and could set off chronic inflammation. Increasingly, chronic inflammation is
thought to underlie a wide range of age-related ailments, from heart disease
and diabetes to cancer and arthritis.
One way to prevent these microbes from destroying the lining of
the gut is to give them something else to snack on, such as fiber from
nutritious whole foods like beans, nuts and seeds and fruits and vegetables.
Other studies have shown that diet can have a substantial effect
on the composition of the microbiome. While the new research did not look
closely at the impact of different foods on changes in the microbiome as we
age, Gibbons said he hopes to examine that in a future study.
“It may be possible to preserve the aging mucus layer in the gut
by increasing the amount of fiber in the diet,” Gibbons said. “Or we might
identify other ways to reduce Bacteroides abundance or increase indole
production through diet. These are not-too-distant future interventions that we
hope to test.”
.jpg)
.jpg)
