Valenzano with Turquoise Killifish, the subject of fecal tranplants

Forget About The Blood Of Teens – Young Poop, Old Poop Is The Latest Thing

The microbiome is emerging as a new player in human health. Researchers recently extended the lifespan of middle-aged animals by nearly 50% by infusing them with the poop of younger fish. [This article first appeared on the website Author: Brady Hartman. ]

Remember the young blood, old blood experiments in which the young blood of mice rejuvenated old mice?

Well, young poop may be even more rejuvenating.

A research team led by Dario Valenzano from the Max Planck Institute in Germany found that transferring the gut bacteria from young fish significantly increased the lifespan of old fish.

In fact, it increased their lifespan by nearly 50%.

The researchers accomplished this feat by replacing the microbiome of the older fish with that of younger ones. All animals, fish and humans alike have a microbiome – a collection of microbes that inhabit our bodies, both inside and out.

Fish Microbiome

For their test subjects, the researchers used the turquoise killifish, a native of a Mozambique and Zimbabwe. The gut microbiomes of a killifish are as nearly diverse as those humans. In fact, we share many of the same gut bacteria. Although short-lived, the tiny killifish suffers from many of the same declines as humans in old age, including muscle loss, increased risk of cancer, neurodegeneration, heart disease, and type 2 diabetes.

Turquoise killifish used for fecal transplant experiments.
Turquoise killifish used for fecal transplant experiments.

One Fish, Two Fish

Valenzano’s team divided the middle-aged fish into two groups. The test group would be treated with a microbiome upgrade and a control group, who would receive no treatment.

To start with a clean slate, or in this case, a clean microbiome, Valenzano first wiped out the gut bacteria of the treated fish with a round of antibiotics. He then transplanted the gut bacteria from young fish into the middle-aged test subjects. He performed a type of fecal transplant.

At the end of the experiment, Valenzano compared the results of the ‘microbiome upgrade.’

Compared to the untreated fish, those who had the fecal transplant lived 41% longer (mean lifespan). In other words, the younger microbiome had significantly lengthened their lives. The procedure also increased their max lifespan by 30%.

Not only that, the researchers noted that the treated fish remained active at advanced ages while the untreated fish had slowed down as they got older.

The treated fish retained youthful energy, while the untreated fish were pooped out.

Microbiome’s Role In Human Health

Making up our microbiome, the microbes that colonize the surface and insides of our bodies are essential for life. We are dependent on these bacteria to produce certain vitamins, regulate our immune system. The tiny critters in our microbiome help digest our food and keep us healthy by protecting us against disease-causing bacteria.

It’s a pretty large ecosystem. Microbes in a healthy human adult are estimated to outnumber human cells by a ratio of ten to one. Even though microbes are only one-tenth to one-hundredth the size of a human cell, the microbiome as a whole may account for up to 2 kilos (five pounds) of adult body weight.

The Aging Microbiome

As we age, so do our microbiomes. All species, fish and human alike, lose diversity in their gut bacteria with advancing age.  Mostly, we lose the bacteria that digest complex carbohydrates.

As Valenzano’s fecal transplant experiment shows; a young & healthy microbiome makes for a young & healthy killifish and vice-versa.

Valenzano is not alone. Other research is also suggesting that the microbiome affects our mood and health. In a different experiment, for example, researchers compared the feces of frail older adults with that of a more robust control group. The researcher found that the poop of the frail elders had lower levels of short-chain fatty acids.

Here’s the explanation:  The microbes in our guts normally make short-chain fatty acids from dietary fiber. These short-chain fatty acids are an important energy source for the colon, and the gut microbiomes of the frail elders had become depleted of the bacteria that perform this chemical conversion.

The microbiome is important to human health. The U.S. Government’s National Institute’s of Health spent 5 years and $115 million to map. Tech giant IBM has also gotten into the game, recently announcing they will study the microbiome’s effects on autoimmune diseases, such as Alzheimer’s, Hashimoto’s, Type 1 Diabetes and Crohn’s Disease.

Bottom Line

Valenzano’s killifish study adds experimental data to the growing body of evidence on the importance of the microbiome to overall health. Valenzano’s study raises the possibility that altering our microbial ecosystem could improve human health and longevity. The research is promising but unproven.

Like the young blood-old blood (parabiosis) technique, the microbiome is becoming an emerging area of anti-aging research. The human microbial ecosystem, however, has not reached the status of other anti-aging interventions, such as the diabetes drug metformin now in clinical trials to test its life-extending abilities;  the lifespan-extending drug rapamycin, also in clinical trials or the spartan dietary practices of Calorie Restriction and the Fasting Mimicking Diet.

Learn More About Fecal Transplants

The microbiome can be altered with an accepted medical procedure known as a fecal transplant. As the linked article shows, some people are eating poop (getting fecal transplants) for therapeutic reasons.

The microbiome is an emerging research field.  High tech firms, including are getting into the act.  Less than a week ago, tech giant IBM announced their plans to study the human microbiome. The mammoth tech firm is investigating the human microbiome’s role in autoimmune disorders.

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Cover Photo: Dario Valenzano holding turquoise killifish. Credit: copyright Frank Vinken – Max Planck Society (via press release).

Max Planck Institute for Biology of Ageing. “GUT BACTERIA AFFECT AGEING” [Press Release].  April 21, 2017. Link to Article. 


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9 Replies to “Forget About The Blood Of Teens – Young Poop, Old Poop Is The Latest Thing”

  1. Mark C

    Nice post.. I thought it was a joke at first, but I saw it was serious about the fish.
    Well written, thanks

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