Scientists discovered that two types of helpful bacteria work better together than alone. When they gave people a probiotic called Lactiplantibacillus plantarum, it didn’t stay in the gut very long. But when they added another bacteria called Leuconostoc citreum, something amazing happened—the first bacteria stuck around much longer and had bigger health benefits. Researchers tested this in both mice and humans, and found that the second bacteria helped by reducing competition from other gut bacteria. This discovery could help make probiotic supplements more effective for people who want to improve their gut health.

The Quick Take

  • What they studied: Whether adding one type of helpful bacteria to another type could help the second bacteria survive longer and work better in the human gut.
  • Who participated: Both mice and humans participated in this study. Researchers gave them probiotics in two separate treatments to see what happened to the bacteria in their digestive systems.
  • Key finding: When Leuconostoc citreum was given together with Lactiplantibacillus plantarum, the amount of the second bacteria more than doubled in the gut compared to giving it alone.
  • What it means for you: This suggests that future probiotic supplements might work better if they contain multiple types of bacteria that work together. However, more research is needed before this becomes a standard recommendation, and you should talk to your doctor before making changes to your probiotic use.

The Research Details

Researchers conducted what’s called an ‘intermittent intervention trial,’ which means they gave people (and mice) probiotics in separate doses with breaks in between, rather than continuously. They then tracked what happened to the bacteria in the gut over time by analyzing stool samples. The scientists looked at which bacteria survived, how many there were, and how they interacted with each other. They also examined the chemical compounds produced in the gut to understand how the bacteria were affecting the environment where they live.

This research approach is important because it shows how probiotics actually behave in real-world conditions, where people don’t take them constantly. By testing in both mice and humans, the researchers could see if the results were consistent across different species. The detailed tracking of bacterial changes helps explain the ‘why’ behind the results, not just the ‘what.’

The study tested findings in both animal and human subjects, which strengthens confidence in the results. The researchers used multiple methods to analyze the data, including looking at bacterial abundance and chemical markers. However, the specific number of human participants wasn’t clearly stated in the abstract, which makes it harder to judge how broadly these findings apply. The research was published in a peer-reviewed journal, meaning other scientists reviewed it before publication.

What the Results Show

The main discovery was that Leuconostoc citreum and Lactiplantibacillus plantarum work together synergistically—meaning they achieve better results together than either could alone. When both bacteria were given together, the amount of Lactiplantibacillus plantarum in the gut more than doubled compared to when it was given alone. This increased survival happened because Leuconostoc citreum changed the gut environment in helpful ways. Specifically, it reduced the number of other bacteria that were competing with Lactiplantibacillus plantarum for space and nutrients. The researchers also found that the combination increased beneficial compounds in the stool, suggesting improved gut health overall.

The study revealed that Lactiplantibacillus plantarum underwent genetic mutations after the second dose, with more mutations appearing in human guts than in mice. This suggests the bacteria were adapting to survive in the gut environment. The researchers identified that the key to success was how Leuconostoc citreum modified the overall bacterial community, essentially creating a friendlier environment for Lactiplantibacillus plantarum to thrive.

Previous research has shown that Lactiplantibacillus plantarum has many potential health benefits, but scientists have struggled with the fact that it doesn’t stay in the gut long-term. This study builds on that knowledge by providing a practical solution—pairing it with another bacteria. The concept of using multiple probiotics together (called ‘synbiotics’) is not entirely new, but this research provides specific evidence for this particular combination and explains the mechanism of how it works.

The abstract doesn’t specify exactly how many human participants were involved, making it difficult to assess how reliable the human results are. The study was relatively short-term, so we don’t know if the benefits last over months or years. The research was conducted with specific strains of bacteria, so results might not apply to other probiotic products. Additionally, while the study shows the bacteria survive better together, it doesn’t fully explain all the health benefits that might result from this improved survival.

The Bottom Line

Based on this research, it appears that combining Leuconostoc citreum with Lactiplantibacillus plantarum may improve how well the second bacteria survives in your gut. However, this is early-stage research, and these specific bacteria combinations are not yet standard recommendations. If you’re interested in trying probiotics, talk to your doctor or a registered dietitian first. They can help you choose products appropriate for your health situation and monitor whether they’re helping you.

This research is most relevant to people interested in probiotics for digestive health, people with digestive issues, and those looking to improve their gut bacteria balance. It’s also important for probiotic manufacturers who want to develop more effective products. People with weakened immune systems should be especially cautious and consult their doctor before trying new probiotics. This research is less immediately relevant to people with no digestive concerns.

Based on this study, the bacteria showed increased survival within the timeframe of the intervention (which appears to be weeks rather than months). However, we don’t know how long the benefits would last if you stopped taking the probiotics, or how long it would take to notice health improvements. Most probiotic effects typically take several weeks to a few months to become noticeable, but individual results vary greatly.

Want to Apply This Research?

  • If using a probiotic app, track your digestive symptoms (bloating, regularity, energy levels) on a daily scale of 1-10 for at least 4-6 weeks. Note which probiotic product you’re using and when you take it. This helps you and your healthcare provider see if the probiotics are actually helping your specific situation.
  • Start by consulting your doctor about whether probiotics are right for you. If approved, choose a probiotic product and take it consistently as directed (usually daily). Use the app to set reminders for taking your probiotic at the same time each day, and log any digestive changes you notice. This consistency is important because probiotics need time to establish themselves in your gut.
  • Over 6-12 weeks, track patterns in your digestive health, energy levels, and overall well-being. Note any changes in bloating, digestion speed, or how you feel after eating. If you’re not seeing improvements after 8-12 weeks of consistent use, discuss with your doctor whether a different probiotic might be better for you. Keep records of which products you’ve tried and your results to share with healthcare providers.

This research is preliminary and has not yet led to approved medical treatments or standard clinical recommendations. The specific bacterial strains studied may not be available in commercial probiotic products. Before starting any probiotic supplement, especially if you have a medical condition, take medications, or have a weakened immune system, consult with your doctor or a registered dietitian. Probiotics are not regulated the same way as medications, and their safety and effectiveness can vary between products. This information is for educational purposes and should not replace professional medical advice.