Your microbiome ages with you — and that’s a problem

These ecosystems appear to change as we age — and these changes can potentially put us at increased risk for age-related diseases. So how can we best take care of them as we age? And could a world-class ecosystem help ward off disease and help us live longer, healthier lives?

That’s a question I’ve been pondering this week, in part because I know a few people who have been on antibiotics for winter infections. These drugs — life-saving as they can be — can cause a mass destruction of gut microbes, wiping out the good along with the bad. What is the best way for people who take them to restore a healthy ecosystem afterwards?

I also came across a recent study in which scientists examined thousands of samples of people’s gut microbial populations to see how they change with age. The standard approach to finding out what microbes live in a person’s gut is to look at the feces. The idea is that we excrete a lot of gut bacteria when we have a bowel movement. Scientists can find out what types and strains of bacteria are present to gauge what’s in your gut.

In this study, a team from University College Cork in Ireland analyzed data previously collected from 21,000 human fecal samples. These had come from people from all over the world, including Europe, North and South America, Asia and Africa. Nineteen nationalities were represented. The samples were all from adults between the ages of 18 and 100.

The authors of this study wanted to get a better grip on what constitutes a “good” microbiome, especially in old age. It has been difficult for microbiologists to figure this out. We know that some bacteria can produce compounds that are good for our gut. For example, some appear to aid digestion while others reduce inflammation.

But when it comes to the ecosystem as a whole, things get more complicated. At the moment, the generally accepted wisdom is that diversity seems to be a good thing – the greater the microbial diversity, the better. Some scientists believe unique microbiomes also have benefits, and that a collection of microbes that differs from the norm can keep you healthy.

The team looked at how the microbiomes of younger people compared to those of older people and how they appeared to change with age. Scientists also looked at how microbial ecosystems changed in response to signs of unhealthy aging such as cognitive decline, frailty and inflammation.

They found that the microbiome appears to change with age and that the ecosystems in our gut as a whole tend to become more unique – it seems we are losing aspects of a general “core” microbiome and are moving towards one Move more towards individual.

But that’s not necessarily a good thing. In fact, this uniqueness appears to be related to unhealthy aging and the development of the age-related symptoms listed above, which we would all rather stall for as long as possible. And measuring diversity alone doesn’t tell us much about whether or not the bugs in our gut are helpful in this regard.

The results confirm what these researchers and others have seen before and challenge the notion that uniqueness is a good thing. Another team has come up with a good analogy known as the Anna Karenina principle of the microbiome: “All happy microbiomes look the same; Every unhappy microbiome is unhappy in its own way.”

The big question, of course, is: what can we do to maintain a happy microbiome? And will it actually help us ward off age-related diseases?

There is a lot of evidence that a diet high in fruits, vegetables, and fiber is generally good for the gut. A few years ago, researchers found that after 12 months of eating a Mediterranean diet — high in olive oil, nuts, legumes and fish, and fruits and vegetables — elderly people saw changes in their microbiome that could benefit their health. These changes have been linked to a reduced risk of developing frailty and cognitive decline.

But on an individual level, we can’t really be sure what impact changing our diet will have. Probiotics are a good example; You can swallow millions of microbes, but that doesn’t mean they’ll survive the journey to your gut. Even if they do get there, we don’t know if they will be able to carve out niches in the existing ecosystem or if they could cause some kind of unwanted disruption. Some microbial ecosystems may respond very well to fermented foods like sauerkraut and kimchi, while others may not.

I personally love kimchi and sauerkraut. If they support my microbiome in a way that protects me from age-related diseases, then that’s just icing on the less microbiome-friendly cake.

To read more, check out these stories from Tech Review’s archive:

At-home microbiome testing can tell you what bugs are in your poop, but not much more than that, as Emily Mullin noted.

According to these experts, industrial-scale fermentation is one of the technologies that is transforming the way we produce and prepare our food.

Can Restricting Your Calorie Intake Help You Live Longer? It seems to work in monkeys, as Katherine Bourzac wrote in 2009.

Adam Piore bravely tried cutting calories himself to see if it could help humans, too. Teaser: Even if you live with the diet longer, you will feel uncomfortable with it.

From the Internet:

Would you pay $15,000 to save your cat’s life? More and more people are turning to expensive surgeries to extend the life of their pets. (The Atlantic)

The World Health Organization will now use the term “mpox” instead of “monkeypox”. which will expire over the next year. (WHO)

After three years in prison, He Jiankui—the scientist behind the infamous “CRISPR babies” – is attempting a comeback. (STAT)

Technology that allows scientists to eavesdrop on the natural world is revealing some truly amazing discoveries. Who knew that sea turtles in the Amazon make more than 200 different sounds? And that they start making noises before they even hatch? (The guard)

These recordings offer many inspirations for musicians. The whale song is particularly popular. (The New Yorker)

Scientists use tiny worms to diagnose pancreatic cancer. Launched in Japan, the test could be available in the US next year. (Reuters)

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