According to Gram Research analysis, selenium deficiency causes a 13% decrease in glucose tolerance and 16% increase in insulin resistance in mice, while adding Ruminococcus torques bacteria had only marginal effects on blood sugar control. However, the bacteria did alter liver protein levels involved in cellular protection, suggesting complex interactions between nutrients and gut bacteria that may influence diabetes risk.
Researchers studied how a specific gut bacteria called Ruminococcus torques interacts with selenium (a nutrient your body needs) to affect blood sugar control in mice. They found that when mice didn’t get enough selenium, they developed signs of diabetes, and adding this bacteria had only small effects on blood sugar levels. However, the bacteria did change how the liver processed certain protective proteins. This research helps scientists understand how gut bacteria, nutrients, and age work together to influence diabetes risk, which could eventually lead to better prevention strategies for people.
Key Statistics
A 2026 study of 16 female mice found that dietary selenium deficiency induced 13% glucose intolerance and 16% insulin resistance compared to mice with adequate selenium intake.
When Ruminococcus torques bacteria were administered to selenium-deficient mice, blood glucose levels decreased slightly at 30 minutes post-injection, but this marginal improvement did not significantly alter overall glucose tolerance, fasting glucose, or insulin resistance.
Selenium deficiency increased the relative abundance of Ruminococcus torques and E. coli in the mouse gut, with E. coli levels further elevated by bacterial gavage treatment, suggesting potential dysbiosis complications.
In selenium-adequate mice, Ruminococcus torques administration decreased liver SELENOP and GPX1 protein levels, while in selenium-deficient mice it increased liver GPX1 levels, demonstrating nutrient-dependent effects on protective liver proteins.
The Quick Take
- What they studied: How a gut bacteria called Ruminococcus torques affects blood sugar control when the body doesn’t have enough selenium
- Who participated: 16 female mice that were fed either normal or selenium-deficient diets for 26 weeks, with half receiving the bacteria treatment in the final 5 weeks
- Key finding: Selenium deficiency caused a 13% increase in glucose intolerance and 16% increase in insulin resistance. Adding the bacteria had only minor effects on blood sugar but did change liver protein levels
- What it means for you: This research suggests that both selenium levels and gut bacteria composition matter for blood sugar control, but the effects are complex. While promising for future treatments, this is early-stage research in mice and doesn’t yet translate to human recommendations
The Research Details
Scientists divided 16 young female mice into groups: some ate normal food with adequate selenium, while others ate food lacking selenium. After 21 weeks, half of each group received daily doses of Ruminococcus torques bacteria through a feeding tube, while the other half received a placebo. The researchers measured blood sugar response, insulin levels, and liver proteins at the end of the 26-week study.
This design allowed researchers to test two things at once: the effect of low selenium and the effect of adding specific bacteria. By measuring multiple outcomes (blood sugar, insulin, and liver proteins), they could see how these factors worked together rather than in isolation.
The study focused on female mice because previous research showed that selenium deficiency affects males and females differently. This sex-specific approach helps explain why some health findings in animals don’t always apply equally to men and women.
Understanding how gut bacteria and nutrients interact is important because both are things we can potentially change through diet or supplements. If scientists can figure out which bacteria help or hurt blood sugar control, they might develop probiotics or dietary changes to prevent diabetes. This research is particularly relevant for older adults, since the study used mice designed to mimic aging in humans.
This is a controlled laboratory study, which means the researchers carefully controlled all variables except the ones they were testing. This type of study is excellent for understanding cause-and-effect relationships. However, it was conducted in mice, not humans, so results may not directly apply to people. The sample size (16 mice) is typical for this type of research but relatively small. The study was published in a peer-reviewed journal, meaning other scientists reviewed it before publication.
What the Results Show
Mice that didn’t get enough selenium developed problems with blood sugar control: their glucose tolerance decreased by 13% and insulin resistance increased by 16% compared to mice eating normal selenium levels. When researchers added Ruminococcus torques bacteria to selenium-deficient mice, blood sugar levels dropped slightly at the 30-minute mark after a glucose injection, but this improvement was small and didn’t significantly improve overall blood sugar control, fasting glucose levels, or insulin resistance.
The bacteria did have effects on liver proteins involved in protecting cells from damage. In mice with adequate selenium, the bacteria decreased two protective proteins (SELENOP and GPX1) in the liver. Interestingly, in selenium-deficient mice, the bacteria increased GPX1 protein levels in the liver, suggesting the bacteria might help the body compensate for low selenium in some ways.
The bacteria also changed the composition of other microbes in the gut. Selenium deficiency increased the amount of E. coli bacteria, and adding Ruminococcus torques made this increase even larger. This is potentially concerning because excessive E. coli can sometimes cause problems.
The study found that selenium deficiency reduced beneficial bacteria like Lactobacillus, Faecalibacterium prausnitzii, and Roseburia species in the gut. These bacteria are known to produce short-chain fatty acids that help protect gut health. Adding Ruminococcus torques didn’t restore these beneficial bacteria, suggesting the treatment didn’t address the underlying bacterial imbalance caused by low selenium. The fact that the bacteria had different effects depending on selenium status shows that nutrient levels and gut bacteria don’t work independently—they interact in complex ways.
Previous research had shown that Ruminococcus torques is associated with type 2 diabetes in humans, which is why researchers chose to study it. This new research confirms that the bacteria can affect blood sugar control, but the effects are more nuanced than expected. The finding that selenium deficiency increases this bacteria’s abundance aligns with earlier observations that low selenium changes gut bacteria composition in aging mice. However, the marginal effect of adding the bacteria suggests that simply introducing one type of bacteria may not be enough to reverse diabetes-like symptoms—the whole bacterial community and nutrient status matter.
This study has several important limitations. First, it was conducted in mice, not humans, so results may not directly apply to people. Second, the study only looked at female mice, so findings may differ in males. Third, the bacteria were given for only 5 weeks, which is a relatively short time—longer studies might show different results. Fourth, the study didn’t measure many other factors that affect blood sugar, like diet composition, exercise, or stress. Finally, the sample size was small (16 mice total), which limits how confident we can be in the results.
The Bottom Line
Based on this research, there are no direct recommendations for human behavior yet. This is early-stage research in mice. However, the findings suggest that maintaining adequate selenium intake may be important for blood sugar control, particularly as we age. People concerned about diabetes risk should focus on proven strategies: eating a balanced diet rich in whole grains, vegetables, and lean proteins; maintaining a healthy weight; exercising regularly; and getting adequate sleep. If you’re concerned about selenium intake, foods like Brazil nuts, fish, and eggs are good sources. Consult your doctor before taking selenium supplements, as too much can be harmful.
This research is most relevant to scientists studying diabetes prevention and gut health. It may eventually interest people at risk for type 2 diabetes, particularly older adults, since the study used aging mice. People with selenium deficiency or those taking medications that affect nutrient absorption might find this relevant. However, this is not yet ready for individual health decisions—it’s a stepping stone toward future research.
Since this is early-stage research in mice, it will likely take 5-10 years of additional human studies before any treatments based on these findings become available. Even then, treatments would probably target specific populations, like older adults or those with documented selenium deficiency.
Frequently Asked Questions
Does taking probiotics help with blood sugar control?
This research suggests probiotics’ effects depend on your selenium status and which specific bacteria are in the supplement. Simply adding one type of bacteria had only minor effects on blood sugar in this study. Proven approaches for blood sugar control include diet, exercise, and weight management. Consult your doctor before starting probiotics.
What is selenium and why does it matter for diabetes?
Selenium is a mineral your body needs to make proteins that protect cells from damage. This study found that low selenium increased diabetes-like symptoms in mice by 13-16%. Good sources include Brazil nuts, fish, eggs, and whole grains. Most people get enough selenium from food, but deficiency can occur with certain health conditions.
Can gut bacteria cause type 2 diabetes?
Gut bacteria appear to influence blood sugar control, but they’re not the sole cause of diabetes. This study shows that Ruminococcus torques is associated with diabetes risk, but adding it alone didn’t fully cause diabetes symptoms. Diabetes develops from multiple factors: genetics, diet, weight, age, and activity level all play important roles alongside gut bacteria.
Should I get tested for selenium deficiency?
Most people get adequate selenium from food, so routine testing isn’t recommended. However, if you have digestive disorders, take certain medications, or follow a restrictive diet, ask your doctor about testing. Symptoms of deficiency include fatigue and muscle weakness, but these are nonspecific. Don’t supplement without medical guidance, as excess selenium is toxic.
How long does it take for probiotics to affect blood sugar?
In this study, bacteria were given for 5 weeks with only marginal effects on blood sugar. Human studies suggest probiotics may take 8-12 weeks to show effects, if any. Individual responses vary greatly. Proven lifestyle changes like diet and exercise show measurable improvements in blood sugar within 2-4 weeks.
Want to Apply This Research?
- Track daily selenium intake (target: 55 micrograms for adults) by logging foods like Brazil nuts, fish, eggs, and whole grains. Also monitor fasting blood glucose levels if you have access to a glucose meter, recording weekly averages to spot trends over time.
- Add one selenium-rich food to your daily diet: one Brazil nut (contains ~96 micrograms selenium), a serving of fish, or an egg. Log this addition in your nutrition tracker to build the habit and ensure consistent intake.
- Create a monthly dashboard showing selenium intake trends and any available blood sugar measurements. Set a reminder to review quarterly and adjust food choices if selenium intake falls below recommended levels. If you have prediabetes or diabetes, share these trends with your healthcare provider during check-ups.
This research was conducted in mice and does not directly apply to human health. Findings about Ruminococcus torques and selenium interactions require further human studies before clinical recommendations can be made. This article is for educational purposes only and should not replace professional medical advice. If you have concerns about blood sugar control, selenium deficiency, or diabetes risk, consult your healthcare provider before making dietary changes or taking supplements. Do not start, stop, or change any medications or supplements without medical guidance.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.