Researchers discovered that selenium, a natural mineral, might help cows and other animals fight dangerous udder infections caused by bacteria. The study found that selenium works by reducing harmful molecules in cells and stopping a type of cell death that makes infections worse. Scientists tested this in lab cells and in mice, and both showed that selenium reduced inflammation and damage. This is important because antibiotics—the current treatment—are becoming less effective as bacteria develop resistance. While this research is promising, it’s still early, and more testing is needed before selenium could be used to treat real infections in animals or people.

The Quick Take

  • What they studied: Whether selenium can help prevent or reduce udder infections (mastitis) by stopping harmful cell damage and inflammation caused by bacteria
  • Who participated: Lab cells from cow udders and mice in controlled experiments; no human participants
  • Key finding: Selenium reduced inflammation, decreased harmful molecules in cells, and prevented a type of cell death that makes infections worse in both lab and animal tests
  • What it means for you: This suggests selenium might become a helpful tool for treating udder infections in dairy animals, but it’s too early to use it instead of antibiotics. More research in real animals and eventually people is needed before any medical use.

The Research Details

The researchers used two different approaches to test their idea. First, they created an infection in lab cells (from cow udders) by exposing them to dead bacteria. They then treated some cells with selenium and measured what happened inside the cells. Second, they fed mice a diet high in selenium and then infected their udders with bacteria to see if the selenium helped protect them. They examined the tissue under a microscope and measured levels of harmful molecules and inflammation markers.

This two-step approach—testing in lab cells first, then in living animals—is a standard way scientists verify that something works before considering human testing. The lab work helps identify how something works, while the animal work shows whether it actually helps in a living body.

Understanding how selenium works against infections is important because antibiotics are becoming less effective. If selenium can reduce infections through a different mechanism (by protecting cells rather than killing bacteria), it might work even when antibiotics fail. This research approach helps identify natural alternatives that could complement or potentially replace antibiotics in the future.

This is original research published in a peer-reviewed scientific journal, which means other experts reviewed it before publication. However, the study was conducted in lab cells and mice, not in real dairy cows or people. The exact number of animals or cells tested wasn’t specified in the abstract. Results from animal studies don’t always translate to humans, so this is still preliminary evidence that needs further testing.

What the Results Show

When bacteria infected the lab cells, several harmful things happened: the cells’ energy-producing structures (mitochondria) became damaged, dangerous molecules called reactive oxygen species (ROS) built up, and a chain reaction of inflammation and cell death began. When researchers added selenium before the infection, these harmful effects were significantly reduced.

In the mice fed selenium, the researchers found that infected udder tissue looked much healthier under the microscope. There were fewer inflammatory cells invading the tissue, and the harmful inflammation markers were lower. The selenium appeared to work by blocking a specific inflammation pathway (called NLRP3) that triggers a type of cell death called pyroptosis.

Interestingly, the results were similar to what happened when researchers used a specific drug (MCC950) designed to block the NLRP3 pathway, suggesting selenium works through this same mechanism. This consistency between the selenium treatment and the targeted drug strengthens the evidence that selenium’s benefit comes from this specific pathway.

The study found that selenium’s protective effect worked similarly to N-acetylcysteine (NAC), a known antioxidant, suggesting that selenium’s antioxidant properties are important to how it works. The research also showed that selenium specifically prevented the activation of gasdermin D, a protein that directly causes the harmful cell death. This suggests selenium might work at multiple levels to protect cells from infection damage.

Previous research had shown that selenium has antioxidant and anti-inflammatory properties, but how it specifically prevented pyroptosis (a type of cell death) in mastitis wasn’t well understood. This study fills that gap by identifying the specific pathway (ROS/NLRP3/Pyroptosis) that selenium affects. The findings align with growing evidence that pyroptosis is a major problem in bacterial infections and that blocking this pathway could help treat infections.

This research was conducted entirely in lab cells and mice, not in actual dairy cows or people. The study doesn’t tell us what dose of selenium would be safe or effective in real animals. The mice were given a very high selenium diet (1.5 mg/kg), which may not reflect realistic exposure levels. Additionally, the bacteria used were inactivated (dead), so the results might differ with live, actively multiplying bacteria. The study also doesn’t compare selenium to actual antibiotic treatment to see which works better.

The Bottom Line

Based on this research, selenium shows promise as a potential future treatment for udder infections, but it’s not ready for practical use yet. Current recommendation: Continue using prescribed antibiotics for mastitis while this research continues. Moderate confidence: This is early-stage research with promising results but limited to lab and animal studies.

Dairy farmers and veterinarians should be aware of this research as a potential future tool. People interested in natural alternatives to antibiotics should understand this is still experimental. This research doesn’t apply to human mastitis treatment at this time. People should not attempt to treat infections with selenium supplements without medical guidance.

If this research continues successfully, it would likely take 5-10 years before selenium-based treatments could be tested in real dairy cows, and potentially much longer before any human applications. This is a very early-stage discovery.

Want to Apply This Research?

  • For dairy farmers using the app: Track selenium levels in feed, infection rates in the herd, and antibiotic usage over time to monitor trends as this research develops
  • Set reminders to monitor herd health metrics and maintain records of any mastitis cases alongside current feed composition to prepare for potential future selenium-based interventions
  • Create a long-term log tracking infection rates, treatment types used, and any dietary changes to establish baseline data that could be valuable if selenium supplementation becomes recommended

This research is preliminary and was conducted in laboratory cells and mice, not in humans or dairy animals. Selenium should not be used to replace antibiotics for treating mastitis or any bacterial infection. Always consult with a veterinarian for animal health concerns or a healthcare provider for human health concerns. Selenium supplements can be toxic at high doses and should only be used under professional guidance. This article is for educational purposes and does not constitute medical or veterinary advice.