Key Takeaways on Ant PoopDo ants poop? Yes. Any creature that eats will poop and ants are no exception. Because ants live in close quarters, they need to protect the colony from their feces so bacteria and fungus doesn't infect their health. This is why they use toilet chambers. Whether they isolate it in a toilet chamber or kick it to the curb, ants don’t keep their waste around. But some ants find a use for that stuff. One such species is the leafcutter ant that takes little clippings of leaves and uses these leaves to grow a very particular fungus that they then eat.Like urban humans, ants live in close quarters. Ant colonies can be home to thousands, even tens of thousands of individuals, depending on the species. And like any creature that eats, ants poop. When you combine close quarters and loads of feces, you have a recipe for disease, says Jessica Ware, curator and division chair of Invertebrate Zoology at the American Museum of Natural History. “Ant poop can harbor bacteria, and because it contains partly undigested food, it can grow bacteria and fungus that could threaten the health of the colony,” Ware says. But ant colonies aren’t seething beds of disease. That’s because ants are scrupulous about hygiene.Ants Do Poop and Ant Toilets Are RealAnt colony underground with ant chambers. (Image Credit: Lidok_L/Shutterstock)To keep themselves and their nests clean, ants have evolved some interesting housekeeping strategies. Some types of ants actually have toilets — or at least something we might call toilets. Their nests are very complicated, with lots of different tunnels and chambers, explains Ware, and one of those chambers is a toilet chamber. Ants don’t visit the toilet when they feel the call of nature. Instead, worker ants who are on latrine duty collect the poop and carry it to the toilet chamber, which is located far away from other parts of the nest. What Does Ant Poop Look Like? This isn’t as messy a chore as it sounds. Like most insects, ants are water-limited, says Ware, so they try to get as much liquid out of their food as possible. This results in small, hard, usually black or brownish pellets of poop. The poop is dry and hard enough so that for ant species that don’t have indoor toilet chambers, the workers can just kick the poop out of the nest.Ants Use Poop as FertilizerWhether they isolate it in a toilet chamber or kick it to the curb, ants don’t keep their waste around. Well, at least most types of ants don’t. Some ants find a use for that stuff. One such species is the leafcutter ant. “They basically take little clippings of leaves and use these leaves to grow a very particular fungus that they then eat,” says Ware. “They don't eat the leaves, they eat the fungus.” And yep, they use their poop to fertilize their crops. “They’re basically gardeners,” Ware says. If you’d like to see leafcutter ants at work in their gardens and you happen to be in the New York City area, drop by the American Museum of Natural History. They have a large colony of fungus-gardening ants on display.Other Insects That Use ToiletsAnts may have toilets, but termites have even wilder ways of dealing with their wastes. Termites and ants might seem similar at first sight, but they aren’t closely related. Ants are more closely related to bees, while termites are more closely related to cockroaches, explains Aram Mikaelyan, an entomologist at North Carolina State University who studies the co-evolution of insects and their gut microbiomes. So ants’ and termites’ styles of social living evolved independently, and their solutions to the waste problem are quite different.“Termites have found a way to not distance themselves from the feces,” says Mikaelyan. “Instead, they use the feces itself as building material.” They’re able to do this because they feed on wood, Mikaelyan explains. When wood passes through the termites’ digestive systems into the poop, it enables a type of bacteria called Actinobacteria. These bacteria are the source of many antibiotics that humans use. (Leafcutter ants also use Actinobacteria to keep their fungus gardens free of parasites.) So that unusual building material acts as a disinfectant. Mikaelyan describes it as “a living disinfectant wall, like a Clorox wall, almost.”Insect HygieneIt may seem surprising that ants and termites are so tidy and concerned with hygiene, but it’s really not uncommon. “Insects in general are cleaner than we think,” says Ware. “We often think of insects as being really gross, but most insects don’t want to lie in their own filth.”Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:The American Society of Microbiology. The Leaf-cutter Ant’s 50 Million Years of FarmingAvery Hurt is a freelance science journalist. In addition to writing for Discover, she writes regularly for a variety of outlets, both print and online, including National Geographic, Science News Explores, Medscape, and WebMD. She’s the author of Bullet With Your Name on It: What You Will Probably Die From and What You Can Do About It, Clerisy Press 2007, as well as several books for young readers. Avery got her start in journalism while attending university, writing for the school newspaper and editing the student non-fiction magazine. Though she writes about all areas of science, she is particularly interested in neuroscience, the science of consciousness, and AI–interests she developed while earning a degree in philosophy.

Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent every weekday. Probiotics are everywhere, claiming to help us poop, restore gut health, and more. They can also be used to help threatened coral reefs. A bacterial probiotic has helped slow the spread of stony coral tissue loss disease (SCTLD) in wild corals in Florida that were already infected with the disease. The findings are detailed in a study published June 5 in the journal Frontiers in Marine Science and show that applying this new probiotic treatment across coral colines helped prevent further tissue loss. What is stony coral tissue loss disease (SCTLD)? SCTLD first emerged in Florida in 2014. In the 11 years since, it has rapidly spread throughout the Caribbean. This mysterious ailment has been confirmed in at least 20 other countries and territories. Other coral pathogens typically target specific species. SCTLD infects more than 30 different species of stony corals, including pillar corals and brain corals. The disease causes the soft tissue in the corals to slough off, leaving behind white patches of exposed skeleton. The disease can devastate an entire coral colony in only a few weeks to months.  A great star coral (Montastraea cavernosa) colony infected with stony coral tissue lossdisease (SCTLD) on the coral reef in Fort Lauderdale, FL. The lesion, where the white band of tissue occurs, typically moves across the coral, killing coral tissue along the way. CREDIT: KellyPitts, Smithsonian. The exact cause of SCTLD is still unknown, but it appears to be linked to some kind of harmful bacteria. Currently, the most common treatment for SCTLD is using a paste that contains the antibiotic amoxicillin on diseased corals. However, antibiotics are not a silver bullet. This amoxicillin balm can temporarily halt SCTLD’s spread, but it needs to be frequently reapplied to the lesions on the corals. This takes time and resources, while increasing the likelihood that the microbes causing SCTLD might develop resistance to amoxicillin and related antibiotics. “Antibiotics do not stop future outbreaks,” Valerie Paul, a study co-author and the head scientist at the Smithsonian Marine Station at Fort Pierce, Florida, said in a statement. “The disease can quickly come back, even on the same coral colonies that have been treated.” Finding the right probiotic Paul and her colleagues have spent over six years investigating whether beneficial microorganisms (aka probiotics) could be a longer lasting alternative to combat this pathogen. Just like humans, corals are host to communities known as microbiomes that are bustling with all different types of bacteria. Some of these miniscule organisms produce antioxidants and vitamins that can help keep their coral hosts healthy.  First, the team looked at the microbiomes of corals that are impervious to SCTLD to try and harvest probiotics from these disease-resistant species. In theory, these could be used to strengthen the microbiomes of susceptible corals.  They tested over 200 strains of bacteria from disease-resistant corals and published a study in 2023 about the probiotic Pseudoalteromonas sp. McH1-7 (or McH1-7 for short). Taken from the great star coral (Montastraea cavernosa), this probiotic produces several antibacterial compounds. Having such a stacked antibacterial toolbox made McH1-7 an ideal candidate to combat a pathogen like SCTLD. They initially tested McH1-7 on live pieces of M. cavernosa and found that the probiotic reliably prevented the spread of SCTLD in the lab. After these successful lab tests, the wild ocean called next. Testing in the ocean The team conducted several field tests on a shallow reef near Fort Lauderdale, focusing on 40 M. cavernosa colonies that showed signs of SCTLD. Some of the corals in these colonies received a paste containing the probiotic McH1-7 that was applied directly to the disease lesions. They treated the other corals with a solution of seawater containing McH1-7 and covered them using weighted plastic bags. The probiotics were administered inside the bag in order to cover the entire coral colony.   “This created a little mini-aquarium that kept the probiotics around each coral colony,” Paul said. For two and a half years, they monitored the colonies, taking multiple rounds of tissue and mucus samples to see how the corals’ microbiomes were changing over time. They found that  the McH1-7 probiotic successfully slowed the spread of SCTLD when it was delivered to the entire colony using the bag and solution method. According to the samples, the probiotic was effective without dominating the corals’ natural microbes.  Kelly Pitts, a research technician with the Smithsonian Marine Station at Ft. Pierce, Floridaand co-lead author of the study treats great star coral (Montaststraea cavernosa) colonies infected with SCTLD with probiotic strain McH1-7 by covering the coral colony in a plastic bag, injecting a probiotic bacteria solution into the bag and leaving the bag for two hours to allow for the bacteria to colonize on the coral. CREDIT: Hunter Noren. Fighting nature with nature While using this probiotic appears to be an effective treatment for SCTLD among the reefs of northern Florida, additional work is needed to see how it could work in other regions. Similar tests on reefs in the Florida Keys have been conducted, with mixed preliminary results, likely due to regional differences in SCTLD. The team believes that probiotics still could become a crucial tool for combatting SCTLD across the Caribbean, especially as scientists fine tune how to administer them. Importantly, these beneficial bacteria support what corals already do naturally.  “Corals are naturally rich with bacteria and it’s not surprising that the bacterial composition is important for their health,” Paul said. “We’re trying to figure out which bacteria can make these vibrant microbiomes even stronger.”

A Deadly Disease Is Eating Away at Caribbean Corals and Wreaking Havoc on Reefs. Could Probiotics Be the Solution? New research suggests the probiotic McH1-7 could help stop the spread of stony coral tissue loss disease among wild corals near Fort Lauderdale, Florida Scientists determined the most effective method of halting the disease was covering a coral colony with a weighted plastic bag, then injecting a seawater solution that contains the probiotic. They left the colony covered for two hours to allow the probiotic bacteria to colonize the coral. Hunter Noren Probiotics can be good for human health. Now, new research suggests they might also help protect coral reefs. A bacterial probiotic helped slow the advance of stony coral tissue loss disease—a fast-spreading and deadly condition—among wild corals in Florida, researchers report today in a new study published in the journal Frontiers in Marine Science. The probiotic may be a good alternative to antibiotics like amoxicillin, which temporarily curb the spread of the disease but must be reapplied frequently. In addition, scientists fear stony coral tissue loss disease may one day become resistant to these antibiotic treatments—just as “superbugs” that infect humans are building resistance to our own drugs. Antibiotics are meant to kill microorganisms, but probiotics are beneficial living microbes. The idea is that a probiotic can be incorporated into corals’ natural microbiomes, ideally offering them longer-lasting protection. First discovered in Florida in 2014, stony coral tissue loss disease attacks the soft tissue of more than 30 different species of coral. Without treatment, the disease eventually kills the corals, and their soft tissue falls off, revealing the white calcium carbonate skeleton below. In just weeks or months, it can devastate a whole colony. Stony coral tissue loss disease can be spread by fish that eat coral, as well as by boaters and divers who do not disinfect their gear. The condition has since expanded its range beyond Florida to reefs throughout the Caribbean. Several years ago, researchers looking at the great star coral (Montastraea cavernosa) discovered a probiotic called Pseudoalteromonas sp. strain McH1-7. Laboratory tests showed McH1-7 stopped or slowed the progression of stony coral tissue loss disease in infected corals. It also helped prevent the disease from spreading to healthy corals. But that was in the lab. Would McH1-7 be similarly effective in the ocean? Researchers were eager to find out, so they set up an experiment on a shallow reef off the coast of Fort Lauderdale. Study co-author Kelly Pitts, a research technician with the Smithsonian Marine Station, applies a paste containing the probiotic directly onto the disease lesion of an infected coral. Hunter Noren Experimenting with wild corals For the study, the scientists focused on 40 great star coral colonies that were showing symptoms of stony coral tissue loss disease. In one experimental condition, the researchers made a paste that contained McH1-7 and applied it directly onto the disease lesions. For comparison, they also applied the same paste, minus the probiotic, to some corals. In another condition, they covered infected coral colonies with weighted plastic bags, then filled the bags with seawater solutions made with and without McH1-7. They left the corals covered for two hours. “This created a little mini-aquarium that kept the probiotics around each coral colony,” says study co-author Valerie Paul, head scientist at the Smithsonian Marine Station at Fort Pierce, Florida, in a statement. The scientists completed all the treatments within the first 4.5 months of the project. Then, they returned periodically to gather tissue and mucus samples from the corals to measure changes to their microbiomes. Over the next 2.5 years, they took photos from a variety of different angles, which they then used to create 3D models that could track the disease’s progression. In the end, the results suggest covering the corals with plastic bags filled with the probiotic seawater solution was the most effective method. More than two years post-treatment, the colonies that received the probiotic bag had lost just 7 percent of their tissue, while colonies in the control bag condition faced 35 percent tissue loss. Scientists applied a probiotic paste directly to disease lesions on some corals. Kelly Pitts The probiotic paste, by contrast, appears to have made the situation worse: The corals that had the probiotic paste applied directly to their lesions lost more tissue than those treated with the control paste, which did not contain McH1-7. “We do not really know what is going on with the probiotic paste treatment,” Paul tells Smithsonian magazine in an email. But she has a few theories. It’s possible the high concentrations of McH1-7 contributed to localized hypoxia, or low-oxygen conditions that further harmed the already stressed corals, she says. Or, the probiotic could have changed the microbiome at the lesion site in some negative way. Another possibility is that McH1-7 produces antibiotics or other substances that were harmful at high concentrations. Amanda Alker, a marine microbiologist at the University of Rhode Island who was not involved with the study, wonders if this finding suggests McH1-7 is beneficial at specific dosages—a question future laboratory research might be able to answer, she tells Smithsonian magazine in an email. She’s also curious to know which specific molecular components of the probiotic are responsible for the increased tissue loss when applied as a paste. More broadly, Alker would like to see additional experiments validating the bag treatment method, but she says this “inventive” technique seems promising. “Their approach is a safer solution than antibiotic treatment methods that have been deployed to combat [stony coral tissue loss disease] in the field so far,” she says. “Further, this is a practical solution that could be implemented widely because it doesn’t require highly specialized equipment and has the ability to be used with any type of microbial solution.” Looking ahead to save reefs Probiotics are likely not a silver bullet for protecting corals. For one, researchers still don’t know exactly what causes stony coral tissue loss disease, which makes it difficult to determine how or why the probiotic works, Paul says. In addition, since the disease has spread to many different parts of the Caribbean, it might be challenging to use the bag treatment technique on all affected colonies. “We would need to develop better methods of deploying the probiotic through time release formulations or other ways to scale up treatments,” Paul says. “Right now, having divers swim around underwater with weighted bags is not a very scalable method.” The researchers have also conducted similar experiments on infected corals located farther south, in the Florida Keys. However, these tests have produced mixed results, probably because of regional differences in stony coral tissue loss disease. This is another hurdle scientists will likely need to overcome if they hope to expand the use of probiotics. “We probably need to develop different probiotics for different coral species and different regions of the Caribbean,” Paul says. Researchers returned to gather samples of tissues and mucus to see how the corals' microbiomes had changed. Hunter Noren Even so, scientists are heartened by the results of the experiments conducted near Fort Lauderdale. With more research, the findings suggest probiotics could be a promising tool for combatting the disease elsewhere. “Coral probiotics is a challenging field, because there are hundreds of different types of bacteria that associate with corals, and there are limitless experiments that need to be performed,” Amy Apprill, a marine chemist at Woods Hole Oceanographic Institution who was not involved with the research, tells Smithsonian magazine in an email. “These researchers made a major advance with their study by demonstrating the utility of whole colony treatment as well as the specific probiotic tested.” Apprill adds that, while antibiotics have been widely used to control stony coral tissue loss disease, scientists haven’t conducted much research to see how these treatments are affecting the plants and creatures that live nearby. “Using a naturally occurring bacterium for disease treatment may result in lessened impacts to other members of the coral reef ecosystem,” she says. Amid rising ocean temperatures, scientists expect to find even more diseased coral colonies in the future. Warmer waters may also allow other pathogens to thrive and proliferate. Against that backdrop, Apprill adds, probiotics and the different methods of applying them will be “major allies” in the fight to save coral reefs. Paul is also optimistic. Through research and field studies, she’s confident researchers will be able to develop interventions that can “help corals better survive changing environments and respond better to diseases and bleaching,” she says. Get the latest stories in your inbox every weekday.

Scientists have discovered a previously unknown bacterium aboard China's Tiangong space station. "It has been named Niallia tiangongensis, and it inhabited the cockpit controls on the station, living in microgravity conditions," reports Wired. From the report: According to China Central Television, the country's national broadcaster, taikonauts (Chinese astronauts) collected swab samples from the space station in May 2023, which were then frozen and sent back to Earth for study. The aim of this work was to investigate the behavior of microorganisms, gathered from a completely sealed environment with a human crew, during space travel, as part of the China Space Station Habitation Area Microbiome Program (CHAMP). A paper published in the Journal of Systematic and Evolutionary Microbiology describes how analysis of samples from the space station revealed this previously unseen bacterial species, which belongs to the genus Niallia. Genomic sequencing showed that its closest terrestrial relative is the bacterium Niallia circulans, although the Tiangong species has substantial genetic differences. [...] It is unclear whether the newly discovered microbe evolved on the space station or whether it is part of the vast sea of as yet unidentified microorganisms on Earth. To date, tens of thousands of bacterial species have been cataloged, although there are estimated to be billions more unclassified species on Earth. The discovery of Niallia tiangongensis will provide a better understanding of the microscopic hazards that the next generation of space travelers will face and help design sanitation protocols for extended missions. It is still too early to determine whether the space bacterium poses any danger to taikonauts aboard Tiangong, although it is known that its terrestrial relative, Niallia circulans, can cause sepsis, especially in immunocompromised people. Read more of this story at Slashdot.

In May 2023, Chinese astronauts swabbed several surfaces of their space station Tiangong (Mandarin for "Heavenly Place"), then sent the samples back to Earth for analysis. The results are now in: the sample contained one bacterium never before seen, according to a report in the International Journal of Systemic and Evolutionary Microbiology.New Bacteria in Space Station The samples were taken, according to the paper, to help keep astronauts healthy in subsequent missions. “Understanding the characteristics of microbes during long-term space missions is essential for safeguarding the health of astronauts and maintaining the functionality of spacecraft,” according to the paper.There are multiple plausible explanations for both the bacteria’s presence and novelty. It could have hitch-hiked with the astronauts and remained more or less the same (although thousands have been identified, there are potentially billions of unknown bacterium on our planet). It could have taken that same route, but mutated and evolved. Or it could be a strain only found in space.Bacteria Similarities and AbilitiesTo get a better picture of the possibilities, it might be best to parse the knowns from the unknowns. First, and perhaps most importantly, it is not completely novel. The bacteria shares enough genetic similarities (two significant stretches of DNA match or are conserved) with Niallia circulans for it to be considered the same genus. Therefore, the authors named it Niallia tiangongensis.Its general appearance also doesn’t appear to be completely out of this world. The paper described it as an “[…] aerobic, spore-forming, rod-shaped strain.”It does appear to have some interesting abilities, though. According to the paper, it shows “a unique ability to hydrolyse gelatin.” This means it can break down some compounds and add components of water to them, perhaps as a way to feed themselves in an environment with little available food.Adaptations to SpaceDifferences in two proteins that resemble those in its cousin hint that it has evolved enhanced abilities to protect itself from some conditions specific to space. Those include tools to create a biofilm it could perhaps hide beneath, and the means to repair damage from radiation, among other abilities.Its terrestrial cousin has one concerning ability. It can cause infection — even sepsis. Knowing whether N. tiangongensis can do the same, and if so, at what level, will likely be the subject of further investigation, since such understanding is a key part of the China Space Station Habitation Area Microbiome Program (CHAMP) that led to its collection, return, and analysis.Article SourcesOur writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:International Journal of Systemic and Evolutionary Microbiology. Niallia tiangongensis sp. nov., isolated from the China Space Station Before joining Discover Magazine, Paul Smaglik spent over 20 years as a science journalist, specializing in U.S. life science policy and global scientific career issues. He began his career in newspapers, but switched to scientific magazines. His work has appeared in publications including Science News, Science, Nature, and Scientific American.

OpinionMay 20, 20254 min readA Good Workout Gets Your Helpful Gut Microbes in Shape, TooA workout boosts the fitness of your gut microbiome. This creates molecules that aids your immune system, metabolism, and moreBy Lydia Denworth Jay BendtThe idea that our workouts could benefit the trillions of microbes that live in our guts—bacteria and viruses that help our immune systems, metabolism, digestion, and other key bodily functions—isn’t obvious. At least it’s not as obvious as the connection between diet and the gut microbiome, as these microbes are called. But evidence is growing that an aerobic workout such as jogging can improve the health of the gut microbes, which in turn improves overall physical health. There are early indications that the relationship works the other way, too: a healthy gut microbiome seems to increase exercise capacity.“When people think about the gut, they default to diet and probiotics,” says Sara Campbell, an exercise physiologist at Rutgers University who specializes in gut microbiota. But now many scientists are “moving toward the reality that exercise can be beneficial for the intestines,” she says.A “healthy” microbiome usually means gut bacteria are abundant and diverse; exercise appears to affect both these qualities. The gut microbes of an elite athlete are more diverse than those of nonathletes or recreational athletes. But a more pertinent issue for health, says Jacob Allen, an exercise physiologist at the University of Illinois Urbana-Champaign, is “what the microbe is actually doing.”On supporting science journalismIf you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.Aerobic exercise encourages activity in bacteria that produce short-chain fatty acids, which provide essential support for physiological processes.One important finding is that aerobic exercise encourages activity in bacteria that produce short-chain fatty acids, which provide essential support for physiological processes. Most fatty acid molecules consist of 16 or 18 carbons, but—as the name suggests—short-chain fatty acids range from just one to six.Of these smaller molecules, butyrate has emerged as an especially important link between exercise and the gut. It supplies energy for a variety of tissues, including the epithelial cells lining the gut, and it can reduce inflammation and improve the ability of cells to take in insulin. Our bodies naturally make a little bit of butyrate, but most is produced by microbes, and its output is boosted by aerobic exercise. (Very few studies have looked at the connection between strength training and butyrate levels, and those that have didn’t find the same effect.)This link between exercise and the gut was barely a glimmer in scientists’ eyes some 15 years ago, when exercise immunologist Marc Cook was a graduate student at the Urbana-Champaign campus. He knew exercise improved symptoms of inflammatory bowel disease, particularly the type called ulcerative colitis. But scientists didn’t understand why. Cook turned to mice to investigate and found that if they ran on a wheel, they were protected against a mouse version of colitis. In addition, there was a sevenfold increase in beneficial bacteria in the lining of the rodents’ colons.In a 2018 study, Allen, Cook (who is now at North Carolina A&T State University), and others tested a gut-health exercise intervention in humans for the first time. They trained both lean and obese people, all of whom were sedentary, to exercise on a treadmill or bike. Everyone started at moderate intensity three days a week and increased to one hour of high-intensity exercise per session.After six weeks all participants showed increases in butyrate and two other short-chain fatty acids, acetate and propionate. They also got the expected benefits of exercise, such as reductions in fat mass and improvements in cardiorespiratory fitness. (All the effects were greater in lean people, a finding that the researchers don’t yet understand.) After a further six weeks in which everyone stopped exercising, microbes in the gut returned to baseline levels, and health benefits decreased.Researchers haven’t fully teased out which effects of exercise can be directly attributed to microbiota versus the other changes brought on by physical activity, but there is a clear difference in gut environment. “We know there’s a slight shunting of blood toward the muscles and away from the gastrointestinal tract during exercise,” Allen says. That causes a small decrease in oxygen in gut tissue. There are changes in pH and temperature within the GI tract as well. Each of these shifts could affect which microbes survive.Studies in humans are complicated by the enormous diversity of microbiomes from person to person and from group to group. Researchers are now trying to account for differences in response. Campbell is investigating variations by sex. Cook is studying the effects of short-chain-fatty-acid-producing bacteria in Black people, who have a high rate of hypertension. In a pilot study, he and his colleagues identified bacteria associated with high blood pressure in Black athletes, and they hope to identify a target for intervention.As for the effects of microbiota on exercise capacity, most of that evidence comes from mice. Animals dosed with antibiotics to kill off their microbiomes exercise less than mice with healthy microbiomes and reach exhaustion faster. Research has also shown that an intact gut microbiota contributes to more muscle development.This evolving research doesn’t change the standard recommendation for human exercise, which is to engage in at least 150 minutes of moderate physical activity a week. But it adds strength to the arguments for doing such activity and may ultimately help explain why people respond to exercise differently. Someday there may even be a way boost the microbiome so that it responds better to time in the gym. Already, though, the science gives new meaning to the idea of gutting out your workout.This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.

A section of the cervixOVERSEAS/COLLECTION CNRI/SCIENCE PHOTO LIBRARY Scientists have coaxed human cells to form a miniature replica of the cervix during pregnancy. This so-called cervix-on-a-chip reveals how inflammation and the vaginal microbiome can contribute to premature birth – and identifies a possible treatment to prevent it. Premature birth – when a baby is born before 37 weeks of pregnancy – affects more than 13 million infants each year and is the second leading cause of childhood mortality and disability. Yet there are no effective…

Pro-tooth decay RFK Jr’s plan to ban fluoride supplements will “hurt rural America,” dentists say In areas without fluoridated water, supplements are the only way to get adequate doses. Beth Mole – May 16, 2025 5:55 pm | 19 Credit: Getty | Flavio Coelho Credit: Getty | Flavio Coelho Story text Size Small Standard Large Width * Standard Wide Links Standard Orange * Subscribers only   Learn more This week, the US health department announced a plan to ban prescription fluoride supplements for children. These ingested fluoride products are dispensed at safe doses by doctors and dentists to prevent tooth decay in children who are unable to get adequate fluoride doses from community water systems—something that may become more common as more states and cities remove or ban fluoride from their water. Both the American Dental Association (ADA) and the American Academy of Pediatrics recommend fluoridating community water and advise prescribing fluoride supplements for children who do not get adequate fluoride dosages through their water. Nevertheless, the Department of Health and Human Services (HHS) under anti-vaccine advocate and conspiracy theorist Robert F. Kennedy Jr states without clear evidence that fluoride supplements harm children's microbiome and pose other health risks. The ADA pushed back strongly, telling Ars Technica in a written statement that the scientific studies the HHS references as evidence of harms "do not in fact demonstrate any harmful effects for the concentrations of fluoride prescribed by physicians and dentists." To support the alleged claim that fluoride harms the gut microbiome, HHS listed two review studies in its announcement. One review, published this year, concludes, "In humans, high doses potentially may be detrimental to the microbiome, whereas ≤ 2 mg/L [sodium fluoride] had positive effects." Community water systems are recommended to have a level of 0.7 mg/L. The other review, published in 2023, said that there wasn't enough human data to make any conclusions. In the announcement, FDA Commissioner Marty Makary was quoted as saying, "The best way to prevent cavities in children is by avoiding excessive sugar intake and good dental hygiene, not by altering a child’s microbiome. For the same reason that fluoride may kill bacteria on teeth, it may also kill intestinal bacteria important for a child’s health." “Harmful” While fluoride can kill bacteria, particularly at high levels, it's used in oral health to inhibit the demineralization of tooth enamel while enhancing the remineralization of tooth surfaces, the ADA clarifies. The best way to get fluoride is through drinking water, the ADA says. But supplements are a safe alternative if a child lives in an area without fluoridated water or if they mostly drink bottled water. Given rampant false and controversial claims about fluoride, more communities are now abandoning it. This week, Florida became the second state after Utah to ban fluoridation state-wide. "Yes, use fluoride for your teeth, that’s fine," Florida Gov. Ron DeSantis said at a news conference after signing the ban into law. "But forcing it in the water supply is basically forced medication on people. They don’t have a choice." ADA President Brett Kessler worries what children in places such as Utah and Florida will do to get adequate fluoride if the ban on supplements goes through. “In non-fluoridated communities, especially rural areas, fluoride supplements are the only chance for individuals to get the appropriate amount of fluoride to prevent tooth decay," Kessler said in the statement. The move will be "particularly harmful to the most vulnerable and those who lack access to care," he added. While Makary said that the FDA will conduct a safety review of  fluoride supplements, the conclusion seems to be foregone, with the HHS writing that it is already "initiating action to remove" the products. The ADA noted that places that have removed fluoride from drinking water, such as Calgary, Canada, and Juneau, Alaska, have seen increases in dental decay, particularly among children and low-income populations. "Proposals like this stand to hurt rural America, not make them healthier," Kessler said. Beth Mole Senior Health Reporter Beth Mole Senior Health Reporter Beth is Ars Technica’s Senior Health Reporter. Beth has a Ph.D. in microbiology from the University of North Carolina at Chapel Hill and attended the Science Communication program at the University of California, Santa Cruz. She specializes in covering infectious diseases, public health, and microbes. 19 Comments

Dr. James Kinross believes gut health is linked to colon cancer risk. Getty Images/ Justine Stoddart 2025-05-13T11:59:36Z Save Saved Read in app This story is available exclusively to Business Insider subscribers. Become an Insider and start reading now. Have an account? Our modern lifestyles are thought to damage our gut health in a way that raises the risk of colon cancer. Lifestyle changes can improve the gut microbiome, which could in turn lower the risk of colon cancer. As well as eating healthily, GI surgeon James Kinross eats enough vitamin D to prevent the disease. Colon cancer is rising in people under 50. James Kinross, a gastrointestinal surgeon who researches how the gut microbiome affects our risk of the disease, told Business Insider that poor gut health could be partly to blame.Research suggests the gut microbiome, the trillions of microbes that live in the digestive tract, has a wide-ranging effect on our health. But our sterile, urbanized lifestyles, appear to have made them less diverse overall and, therefore, weaker, according to Kinross, who is based at Imperial College London."You're seeing a generational loss in our internal ecology, which is being hammered with a series of environmental hits that it simply cannot adapt to," he said, referring to factors including microplastics, ultra-processed foods, and minimal access to nature. Many studies have linked But, the gut microbiome is changeable, meaning there are things we can do to increase its diversity, which in turn could help lower colon cancer risk. "It is an ecosystem which you can adapt, and you can modify," he said.Kinross previously shared with BI how he eats to boost his gut microbiome. He shared the three things he does aside from healthy eating to lower his colon cancer risk.Don't take antibiotics if you don't need to Kinross limits his antibiotic use where possible because the medication disrupts the gut microbiome. Trevor Williams/Getty Images As a surgeon, Kinross is acutely aware that antibiotics are often necessary and save millions of lives each year, but he believes we use them too liberally — particularly to treat viral infections they can't tackle."In my house, to qualify for antibiotics, you've really got to have a pathogen that you need treated," Kinross said.Kinross and his family limit their use of antibiotics as much as possible because taking them can disrupt the ecosystem of the gut microbiome, killing off good bacteria along with pathogens, and reducing diversity.He likened it to pouring weed killer all over your garden. "Your garden won't really grow into a lovely garden full of wild meadows and flowers and color. It will just be brown and lifeless," he said.Take vitamin DKinross takes a vitamin D supplement because evidence suggests that having enough of the nutrient is important for gut health. Vitamin D is crucial for several biological processes, including calcium absorption and cellular repair — but also keeps the lining of the small intestine strong. If the lining becomes weak, microbes can pass through it into the bloodstream and cause inflammation. Chronic inflammation is linked to a higher risk of chronic diseases, including cancer.Vitamin D is found in foods including oily fish, egg yolks, and red meat, as well as from sunlight. In countries with climates like the UK's, where Kinross lives, it can be difficult to get enough vitamin D in the colder months, and residents are advised to supplement from October to March.Socialize Social connections are a pillar of health. pixdeluxe/Getty Images Kinross goes cycling with friends regularly and makes sure to sit down to eat dinner with his family in the evenings. As well as being a pillar of overall health, research suggests that socializing positively impacts the composition of our gut microbiomes, Kinross said.We exchange microbes through physical touch, and studies have found that friends, family members, and spouses have similar gut microbes to one another.A 2024 study published in the journal Nature, based on 1,787 adults from 18 isolated villages in Honduras, found that people in the same social network shared more similarities in their gut microbiomes compared to those outside of it. This was regardless of diet, water sources, and medications. Spouses and people living together had the highest amount of microbial sharing, but the phenomenon still occurred among friends and even friends of friends."Our social interactions, our real-world social interactions, define so much of our health," Kinross said. "It's good for all aspects of our health. It's good for our mental health, it's good for our cardiovascular health. It's good for everything. But if you're not having real-world social interaction, you are not really optimizing your gut health, I believe." Recommended video