Postbiotics May Prevent Diabetes in Obesity

You’ve likely heard about probiotics—live bacteria with long, colorful names found in your yogurt that help generate a happy gut. You may have even heard of prebiotics, which are compounds that have a beneficial effect on the bacteria in your body. But you’re probably less familiar with postbiotics—factors derived from bacteria that can also have a positive impact on our health.

Researchers at McMaster University who study diabetes and obesity have discovered a postbiotic factor called MDP that prevents pre-diabetic obese mice from developing diabetes. Their surprising results were recently published in Cell Metabolism.

When bacteria in the gut become chronically out of balance—known as intestinal dysbiosis [PDF]—a person can become insulin resistant, or prediabetic. Dysbiosis is often found in people with obesity. “Key markers on the road to diabetes are insulin sensitivity and insulin resistance—how well that hormone can lower blood glucose,” Jon Schertzer, lead study author and assistant professor of biochemistry at McMaster University tells Mental Floss. Insulin’s job is to bring your blood glucose back up to normal after you eat or drink something. If you’re insulin resistant, or improperly sensitive, insulin can’t do its job properly. “What a postbiotic does is allow the insulin to do a better job,” he says.

Schertzer’s team sought to investigate whether postbiotics could have an impact on obesity before a person becomes overtly diabetic. “The focus of this study is prediabetes—the stage before the overt disease has developed and it’s still reversible. Obesity is the biggest risk factor for prediabetes,” he explains.

The team found that a postbiotic called muramyl dipeptide (MDP), derived from a bacterial cell wall, was able to reduce insulin resistance in mouse models—regardless of weight loss or changes in the intestinal microbiome during obesity.

To test this, Schertzer separated mice into two groups. One group was given MDP at the same time as they were fed a high-fat diet intended to cause obesity. In that experiment, the mice were given MDP four days per week for five weeks. The MDP injections improved insulin and glucose tolerance after five weeks—remarkably, without altering body mass or fatty tissue levels.

In the second group, the team fed the mice into a state of obesity over 10 weeks, putting them into a state of prediabetes. Then they injected MDP into the mice three times over three days and saw a rapid improvement in blood glucose by the third day. “It’s not that the injection itself is lowering blood glucose, but those three short duration injections set the program up to allow insulin to work better,” he says.

When the body senses MDP is present, it increases the amount of a protein in fat tissue, called IR4, which sends out signals that lower blood glucose. “We don’t fully understand how it signals the body to lower blood glucose,” he admits. “We do know it reduces inflammation.”

While that may not sound dramatic, he says they were quite surprised, given that the typical immune response is to increase inflammation. “The postbiotic actually reduced inflammation in fat tissue, which are the tissues that control blood glucose,” he says.

While the results are exciting, he’s quick to point out that “we’re interested in discovery. We’ll leave the clinical aspect to clinicians.” They’d like to achieve a version of MDP that could be taken orally and not injected, but more research will be required. Plus, postbiotics can be a finicky area of research. He describes testing a different postbiotic that's a “a close cousin" to MDP, being "a different type of cell wall that was different by only one peptide.” But that postbiotic made glucose tolerance and inflammation much worse.

However, they also tested what’s called an “orphan drug”—approved only for clinical trials but not likely to make the drug company any money—called mifamurtide, typically used in treating bone cancers. Mifamurtide is synthetic, but chemically identical to the MDP postbiotic. It, too, improved blood glucose and insulin tolerance when administered to mice. The promising part about it is that since the drug is already given to humans in clinical trials, “it could make the transition to humans far more rapid,” he says.

One of their next steps is to expand the models they’re using, starting with age-induced diabetes. “Obesity is only one factor that promotes diabetes,” he says.

The most pressing question now, he says, is “to understand what is actually happening in the gut during obesity.” This compound promises a future in which obesity would pose less of a risk factor for diabetes. And postbiotics hold a lot of potential for future research.

“Postbiotics are a new source of drugs. Bacteria have different physiology from us, and can make all kinds of things that we can’t make,” Schertzer says.

Tonight, the Lyrid Meteor Shower Peaks on Earth Day

iStock/dmoralesf
iStock/dmoralesf

Tonight, look up and you might see shooting stars streaking across the sky. On the night of Monday, April 22—Earth Day—and the morning of Tuesday, April 23, the Lyrid meteor shower will peak over the Northern Hemisphere. Make some time for the celestial show and you'll probably see meteors zooming across the heavens every few minutes. Here is everything you need to know about this meteor shower.

What is the Lyrid meteor shower?

Every 415.5 years, the comet Thatcher circles the Sun in a highly eccentric orbit shaped almost like a cat's eye. At its farthest from the Sun, it's billions of miles from Pluto; at its nearest, it swings between the Earth and Mars. (The last time it was near the Earth was in 1861, and it won't be that close again until 2280.) That's quite a journey, and more pressingly, quite a variation in temperature. The closer it gets to the Sun, the more debris it sheds. That debris is what you're seeing when you see a meteor shower: dust-sized particles slamming into the Earth's atmosphere at tens of thousands of miles per hour. In a competition between the two, the Earth is going to win, and "shooting stars" are the result of energy released as the particles are vaporized.

The comet was spotted on April 4, 1861 by A.E. Thatcher, an amateur skywatcher in New York City, earning him kudos from the noted astronomer Sir John Herschel. Clues to the comet's discovery are in its astronomical designation, C/1861 G1. The "C" means it's a long-period comet with an orbit of more than 200 years; "G" stands for the first half of April, and the "1" indicates it was the first comet discovered in that timeframe.

Sightings of the Lyrid meteor shower—named after Lyra, the constellation it appears to originate from—are much older; the first record dates to 7th-century BCE China.

How to See the Lyrid Meteor Shower

Monday night marks a waning gibbous Moon (just after the full Moon), which will reflect a significant amount of light. You're going to need to get away from local light pollution and find truly dark skies, and to completely avoid smartphones, flashlights, car headlights, or dome lights. The goal is to let your eyes adjust totally to the darkness: Find your viewing area, lay out your blanket, lay down, look up, and wait. In an hour, you'll be able to see the night sky with great—and if you've never done this before, surprising—clarity. Don't touch the smartphone or you'll undo all your hard ocular work.

Where is the nearest dark sky to where you live? You can find out on the Dark Site Finder map. And because the shower peaks on a Monday night—when you can expect to see 20 meteors per hour—your local astronomy club is very likely going to have an event to celebrate the Lyrid meteor shower. Looking for a local club? Sky & Telescope has you covered.

Other Visible Bodies During the Lyrid meteor shower

You don't need a telescope to see a meteor shower, but if you bring one, aim it south to find Jupiter. It's the bright, unblinking spot in the sky. With a telescope, you should be able to make out its stripes. Those five stars surrounding it are the constellation Libra. You'll notice also four tiny points of light nearby. Those are the Galilean moons: Io, Europa, Ganymede, and Callisto. When Galileo discovered those moons in 1610, he was able to prove the Copernican model of heliocentricity: that the Earth goes around the Sun.

What to Do if There's Bad Weather During the Lyrid Meteor Shower

First: Don't panic. The shower peaks on the early morning of April 23. But it doesn't end that day. You can try again on April 24 and 25, though the numbers of meteors will likely diminish. The Lyrid meteor shower will be back next year, and the year after, and so on. But if you are eager for another show, on May 5, the Eta Aquarids will be at their strongest. The night sky always delivers.

Does the Full Moon Really Make People Act Crazy?

iStock.com/voraorn
iStock.com/voraorn

Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the Moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.

This belief that the Moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the Moon are linked [PDF].

To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

When the researchers compared the time of the visits to the phases of the Moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception—in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

So rest easy (or maybe not): If people seem to act crazy during the full Moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.

This story was updated in 2019.

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