Dogs may hold the key to slow aging in humans

Growing old is not just about time. It is chemistry, biology, and chance working together in every cell.

For decades, scientists have searched for measurable signs in the body that tell how well life is aging. These signs, called biomarkers, can reveal more than just years – they can whisper how healthy the body truly is.

Now, scientists studying dogs have found molecular traces that could help explain aging in both animals and humans. These findings could reshape how researchers study longevity.

By tracking these molecules, scientists may soon measure not only how fast aging happens but also how to slow it down.

The discovery offers a glimpse into a shared biological story between species, written in the language of chemistry, resilience, and time.

Dogs as aging mirrors

Researchers from Tufts University and the University of Washington analyzed blood from almost 800 dogs in the Dog Aging Project.

These dogs live in homes, eat family food, and breathe the same air as their owners. Their shared environments make them powerful models for human biology.

The study revealed that about 40 percent of small molecules in the dogs’ blood shifted with age.

“These molecules, known as metabolites, are basically the building blocks of life,” said Daniel Promislow, senior scientist and scientific advisor at the HNRCA.

“They serve as the raw materials for forming proteins, DNA, and other cellular components, and play a critical role in keeping cells alive.”

The discovery hints that aging reshapes metabolism deeply. The body does not just slow down – it changes the way its chemistry works.

Aging clues in dogs

Among the thousands of molecules examined, one group stood out. These were post-translationally modified amino acids, or ptmAAs. They form when proteins break apart or when gut bacteria tinker with nutrients during digestion.

The researchers found that ptmAAs appeared more often in older dogs, no matter the breed or size.

“These metabolites are created in two ways in the body,” explained Promislow. “The bacteria in our guts can make ptmAAs as we digest our food, or they can show up when proteins break down.”

This discovery connects aging to how the body manages its proteins. When these molecules accumulate, they might signal slower recycling of proteins or rising wear inside cells. Each change reflects a shift in how the body maintains itself over time.

Kidneys show aging impacts

One pattern stood out clearly. Dogs with weaker kidneys carried higher levels of these modified amino acids.

Kidneys normally filter protein byproducts out of the blood. When filtration weakens, these chemicals stay behind, building up in the bloodstream.

That buildup may reveal how well the body clears its own waste. It also helps explain why some animals seem to age more gently.

Stronger kidney function might keep the blood cleaner and the body healthier longer. Because humans share similar biology, the finding may apply to us too.

Tracking dogs over years

The study captured a single moment – a comparison between young and old dogs. But aging is a story written slowly.

Researchers plan to follow the same dogs for years to see how these metabolites change. Tracking individual dogs will help reveal whether these molecules predict future health, not just describe the past.

The team will also explore how gut microbes influence these aging signals. Changes in the gut community can alter metabolism and immune balance.

If certain bacteria drive the rise of ptmAAs, targeting those microbes could one day help slow aging itself.

What dogs teach about aging

By comparing results in dogs and humans, scientists hope to find universal signs of aging. Such biomarkers could guide new treatments, showing whether an intervention truly keeps the body younger.

The Dog Aging Project’s massive dataset, rich with genetic, environmental, and lifestyle information, makes that possible.

Promislow sees a shared benefit ahead. “We have a tremendous opportunity to understand the causes and consequences of aging and to discover ways to ensure that both species enjoy the healthiest aging trajectory possible.”

Dogs may not live as long as humans, but their lives unfold faster – and in that speed, science can read the script of aging. Every wagging tail and every heartbeat might hold clues to how both species can stay stronger, healthier, and more vibrant for longer.

Their shorter lifespans allow scientists to observe decades of biological change within years, revealing how organs adapt, how cells repair damage, and how lifestyle influences longevity.

The study is published in the journal Aging Cell.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates. 

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–