Researchers tested whether fermented black soybeans and a grain called adlay could help mice on unhealthy diets lose weight and improve their metabolism. The fermented version worked better than the unfermented version at reducing weight gain, belly fat, and liver problems while improving how the body handles sugar. The study suggests that fermentation—a natural process that breaks down food—makes these foods more powerful at fighting metabolic syndrome, a condition that increases disease risk. While this is promising, the research was done in mice, so we need human studies to know if the same benefits apply to people.

The Quick Take

  • What they studied: Whether fermented black soybeans and adlay (a grain) could help reduce weight gain, belly fat, and metabolic problems in mice eating unhealthy diets high in fat and sugar.
  • Who participated: Laboratory mice (C57BL/6J strain) that were fed a high-fat, high-sugar diet to mimic unhealthy human eating patterns. The study compared mice receiving fermented versus unfermented versions of the food.
  • Key finding: Mice that received the fermented version gained less weight, had less belly fat, better blood sugar control, and healthier livers compared to mice on the same diet without the fermented food supplement.
  • What it means for you: This suggests that fermented soybean and adlay products might help people with metabolic syndrome lose weight and improve their health. However, this was tested in mice, so human studies are needed before we can recommend it as a treatment. If you have metabolic syndrome, talk to your doctor before trying new supplements.

The Research Details

Scientists took mice and fed them unhealthy diets high in fat and sugar to create metabolic syndrome—a condition similar to what happens in some humans who eat poorly. They then gave some mice fermented black soybeans and adlay (a grain), while others got the unfermented version or no supplement at all. Fermentation is a natural process where bacteria break down food, making it easier to digest and potentially more beneficial.

The researchers measured multiple things over time: how much weight the mice gained, how much belly fat they developed, their blood sugar levels, liver health, and the bacteria living in their digestive systems. They also examined the mice’s liver cells to understand which biological pathways were activated by the fermented food.

This type of study is important because it allows researchers to carefully control all variables and measure specific biological changes that would be difficult to study in humans. The findings can then guide future human research.

Understanding how fermented foods affect the body’s metabolism and gut bacteria is important because metabolic syndrome affects millions of people and increases the risk of heart disease, diabetes, and fatty liver disease. If fermented foods can help reverse these problems, they could offer a natural, food-based approach to treatment. This research also shows how fermentation changes food at a biological level, which helps explain why fermented foods have been valued in many cultures for centuries.

This study was published in the Journal of Agricultural and Food Chemistry, a respected scientific journal. The researchers measured multiple biological markers and used established laboratory methods. However, the study was conducted in mice, not humans, so results may not directly apply to people. The abstract doesn’t specify the exact number of mice used, which would help assess study size. Additionally, animal studies often show more dramatic results than human studies, so caution is warranted when interpreting the findings.

What the Results Show

The fermented version of black soybeans and adlay (called FBA) significantly outperformed the unfermented version (UFBA) in multiple ways. Mice receiving FBA gained less weight overall and accumulated less dangerous belly fat compared to control mice. Their blood fat levels improved, meaning cholesterol and triglycerides decreased. Most importantly, their livers became healthier—they developed less fatty liver disease, a serious condition that can lead to liver damage.

The fermented food also improved how well the mice’s bodies handled sugar and insulin, suggesting better blood sugar control. These improvements happened because fermentation activated specific biological pathways in the liver that help burn fat and prevent the body from making too much new fat. The researchers identified two key pathways: AMPK-SIRT1 and PI3K-Akt, which are like switches that control whether the body stores or burns fat.

Another major finding involved the bacteria living in the mice’s digestive systems. The unhealthy diet had created an imbalance in these bacteria (called dysbiosis), but the fermented food helped restore a healthier balance. Specifically, it reduced the ratio of Firmicutes to Bacteroidetes bacteria and increased a beneficial substance called propionate that the bacteria produce.

The study found that fermentation itself was crucial—the unfermented version of the same foods provided some benefits but significantly fewer than the fermented version. This demonstrates that the fermentation process fundamentally changes how the food affects the body. The research also showed that the benefits extended beyond simple weight loss; the improvements in liver health and metabolic markers suggest deeper biological healing was occurring.

Previous research has shown that fermented foods can improve gut health and metabolism, but this study provides more detailed information about exactly which biological pathways are involved and how fermentation enhances these effects. The findings align with growing evidence that gut bacteria play a major role in metabolic health and that fermented foods can help restore healthy bacterial communities. This research builds on decades of traditional knowledge about fermented foods in Asian cuisines.

The most important limitation is that this research was conducted in mice, not humans. Mice metabolize food differently than people, and results don’t always translate directly to human health. The study doesn’t specify how many mice were used, making it harder to assess the statistical strength of the findings. Additionally, the study used mice with artificially induced metabolic syndrome from extreme diets, which may not perfectly mirror the human condition. The research also doesn’t tell us the optimal dose for humans or how long benefits would last. Finally, we don’t know if these benefits would occur in people already taking medications for metabolic syndrome.

The Bottom Line

Based on this research, fermented black soybean and adlay products appear promising for metabolic health, but human studies are needed before making strong recommendations. If you have metabolic syndrome, discuss fermented soy products with your doctor as a potential complementary approach alongside proven treatments like diet and exercise. The evidence is moderate—promising but not yet definitive for human use.

People with metabolic syndrome, prediabetes, fatty liver disease, or high cholesterol should find this research interesting and worth discussing with their healthcare provider. People interested in fermented foods and natural health approaches may also benefit from following this research. However, people taking medications for blood sugar or cholesterol control should consult their doctor before adding new supplements, as fermented foods might interact with medications.

In the mouse study, benefits appeared over several weeks of consistent consumption. In humans, metabolic changes typically take 4-12 weeks to become noticeable, though some improvements in blood markers might appear sooner. Realistic expectations would be gradual improvement over 2-3 months of consistent use, combined with healthy diet and exercise.

Want to Apply This Research?

  • Track weekly weight, waist circumference, and energy levels. Also monitor consumption of fermented soy products (servings per week) to correlate intake with health metrics. Users could rate digestive comfort on a 1-10 scale daily.
  • Add one serving of fermented black soybean or adlay product to your diet 3-5 times per week. Start with small portions to allow your digestive system to adjust. Pair this with tracking your weight and how you feel to monitor personal results.
  • Create a 12-week tracking plan measuring weight, waist circumference, energy levels, and digestive health weekly. Users should also note any changes in blood sugar levels if they have a glucose monitor. Monthly check-ins with blood work (if available) would show changes in cholesterol and liver markers.

This research was conducted in laboratory mice and has not yet been tested in humans. The findings are promising but preliminary. If you have metabolic syndrome, prediabetes, fatty liver disease, or take medications for blood sugar or cholesterol control, consult your healthcare provider before significantly changing your diet or adding new supplements. Fermented foods may interact with certain medications. This information is for educational purposes and should not replace professional medical advice. Always discuss dietary changes with your doctor, especially if you have existing health conditions.