Scientists tested whether fermented rice bran—a supplement made from rice bran mixed with helpful bacteria—could help mice fight off the flu virus. They gave some mice this supplement before or after getting infected with flu. The results showed that mice receiving fermented rice bran had less severe illness, recovered faster, and their bodies made more protective antibodies to fight the virus. This worked for both healthy mice and mice with weakened immune systems. While these are promising results, more research in humans is needed before we know if this supplement could help people with the flu.

The Quick Take

  • What they studied: Whether a fermented rice bran supplement could help mice fight off influenza (flu) virus infection and boost their immune system
  • Who participated: Laboratory mice (BALB/c strain) in two groups: healthy mice and mice with weakened immune systems. The exact number of mice wasn’t specified in the abstract
  • Key finding: Mice that received fermented rice bran supplement lost less weight during flu infection, had lower virus levels in their lungs, and produced more protective antibodies compared to mice that didn’t receive the supplement. These benefits appeared in both healthy and immunocompromised mice
  • What it means for you: This research suggests fermented rice bran might be worth studying further as a potential flu-fighting supplement, especially for elderly people and those with weak immune systems. However, this was only tested in mice, so we cannot yet say if it would work the same way in humans. Talk to your doctor before trying any new supplements

The Research Details

Researchers created fermented rice bran by mixing rice bran with four types of beneficial bacteria and fungi. They then gave this supplement to mice in different ways: some mice received it daily for 1-2 months before being exposed to flu virus, while others received it right after infection. The scientists measured several things to see if the supplement helped: how much weight the mice lost, how much virus was in their lungs, and how many protective antibodies their bodies made.

The study included two types of mice: healthy mice and mice with weakened immune systems (made weak using a cancer drug). This allowed researchers to see if the supplement worked differently depending on immune system strength. They tracked the mice for 14 days after infection and examined their lungs and intestines for damage.

Testing in mice first is important because it helps scientists understand how a treatment might work before testing it in humans. Using both healthy and immunocompromised mice is especially valuable because elderly people and those with weak immune systems are most at risk from serious flu complications. This study design helps answer whether the supplement could help the people who need it most

This study was published in a peer-reviewed journal, meaning other scientists reviewed it before publication. The researchers tested their supplement in a controlled laboratory setting, which allows for precise measurements. However, the abstract doesn’t specify exactly how many mice were used, which makes it harder to evaluate the strength of the results. Animal studies are a necessary first step, but results don’t always translate directly to humans

What the Results Show

Mice receiving fermented rice bran showed significant protection against flu infection. In healthy mice, the supplement reduced weight loss during infection and helped them recover faster. More importantly, the virus levels in their lungs were lower just 3 days after infection, suggesting the supplement helped fight the virus early.

The supplement boosted the immune system in multiple ways. Mice that received fermented rice bran produced more neutralizing antibodies—special proteins that help the body recognize and destroy flu viruses. These protective antibodies appeared both in the bloodstream and in the respiratory tract (lungs and airways), which is important because that’s where the flu virus attacks.

In immunocompromised mice (those with weakened immune systems), the benefits were even more impressive. When given the supplement for a month before infection, these mice showed significant protection: less weight loss, lower virus levels, and better antibody production. Importantly, the supplement also protected the intestinal lining from damage, which is significant because the gut is important for overall immune function.

Timing mattered for the results. Mice that received the supplement before getting sick showed stronger protection than those who started it after infection. However, even mice that started the supplement after infection still showed some protective benefits, just not as strong

The supplement increased levels of interferon-gamma (IFN-γ), a chemical messenger that helps coordinate immune responses. This increase was seen on days 3 and 14 after infection in the blood of treated mice. The supplement also increased immunoglobulin A (IgA) levels in the lungs and intestines—these are antibodies that protect the mucous membranes where viruses enter the body. The preservation of normal intestinal structure in immunocompromised mice suggests the supplement may protect gut health during infection, which could have broader health benefits

This research builds on earlier observations that fermented rice bran has various biological activities. Previous studies suggested it might have anti-viral properties, but this is one of the first studies specifically testing it against influenza virus. The finding that the supplement works in both healthy and immunocompromised mice is particularly novel and suggests it might be beneficial for vulnerable populations. The results align with growing research showing that fermented foods and beneficial bacteria can support immune function

This study was conducted only in mice, so we cannot directly apply these results to humans yet. The abstract doesn’t specify the exact number of mice used, making it difficult to assess the statistical strength of the findings. The study used a specific strain of mice (BALB/c), which may not represent how different people would respond. The supplement was given in specific doses (20 mg/day) that may not translate directly to human dosing. Additionally, this was a laboratory study with controlled conditions, which is very different from real-world situations where people are exposed to various strains of flu and have different lifestyles

The Bottom Line

Based on this mouse study, fermented rice bran appears promising as a potential immune-supporting supplement, particularly if taken before potential flu exposure. However, this is preliminary evidence from animal studies only. If you’re interested in trying fermented rice bran, consult your doctor first—especially if you’re elderly, have a weakened immune system, or take medications. The standard flu vaccine remains the most proven way to prevent influenza. This supplement should not replace vaccination or medical treatment for flu

This research is most relevant to elderly people and those with weakened immune systems, as these groups showed the most benefit in the study. People interested in natural immune support may find this interesting, though more human research is needed. Healthcare providers caring for immunocompromised patients should note this emerging research. People should NOT rely on this supplement alone to prevent flu—vaccination is still essential. Anyone with serious health conditions should consult their doctor before trying new supplements

In the mouse study, benefits appeared relatively quickly—virus levels dropped by day 3, and immune markers improved by day 14. If similar timing applied to humans, you might expect to see some benefits within weeks of starting supplementation. However, this is speculative, and human studies would need to confirm this timeline. For prevention, the study suggests taking the supplement for at least a month before potential exposure may provide the strongest protection

Want to Apply This Research?

  • If using fermented rice bran supplement, track daily intake (yes/no), any cold or flu symptoms (fever, cough, congestion), and overall energy levels. Rate symptom severity on a 1-10 scale if you do get sick, and note how many days until recovery
  • Start taking a fermented rice bran supplement daily during flu season (typically October-March in the Northern Hemisphere), ideally beginning a month before peak flu exposure. Combine this with other proven measures: get your annual flu vaccine, wash hands frequently, and maintain good sleep and nutrition
  • Track supplement adherence weekly and monitor for any illness over a 3-6 month period during flu season. Compare your illness frequency and severity to previous years. Keep notes on any digestive changes, as fermented foods can affect the gut. If you do get sick, document symptom onset, peak severity, and recovery time to see if the supplement appears to help

This research was conducted in mice and has not been tested in humans. Results from animal studies do not always translate to humans. Fermented rice bran supplements are not approved by the FDA to treat or prevent influenza. This supplement should not replace the flu vaccine, which remains the most effective way to prevent influenza. If you are elderly, immunocompromised, pregnant, or taking medications, consult your healthcare provider before starting any new supplement. If you develop flu symptoms, seek medical attention promptly. This information is for educational purposes only and should not be considered medical advice