Fermented African locust bean may boost gut health, study finds

Experts say Parkia biglobosa, commonly known as African locust bean or iru in West Africa, may improve gut health by altering the balance of bacteria in the digestive system.

In a recent study, researchers found that mice fed with African locust bean developed higher levels of beneficial gut bacteria such as Firmicutes and Bacteroidota, which support digestion and energy metabolism.

Fermented foods like African locust bean have long been used in African diets and traditional medicine to manage conditions such as stomach pain and ulcers. However, scientific evidence explaining how these foods work has remained limited.

The new study, published in Food Chemistry Advances, examined how fermented African locust bean affects the gut microbiome—the community of microorganisms living in the digestive system that plays a key role in digestion, immunity, and overall health.

Led by Joseph Olusegun Omotayo, the researchers fed different groups of mice a standard diet, a diet supplemented with fermented African locust bean, or diets containing three different chemical seasonings.

Over a 13-day period, the scientists monitored the animals’ weight, gut bacteria composition, and the health of major organs including the liver, kidneys, and heart.

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Results showed that mice that consumed iru had higher levels of beneficial bacteria, including Firmicutes and Bacteroidota, which are known to support digestion, energy use, and overall gut balance.

The researchers also observed increased levels of bacteria associated with the production of short-chain fatty acids (SCFAs)—compounds that protect the stomach lining, reduce inflammation, and support digestive health.

Importantly, the study found that African locust bean did not cause damage to the liver, heart, or kidneys of the mice. In contrast, some chemical seasonings triggered inflammation and tissue damage in these organs.

Laboratory analysis further showed that fermented African locust bean is rich in protein, fiber, and polyphenols, nutrients that help feed beneficial gut bacteria and promote the production of SCFAs.

Mice fed with chemical seasonings, however, showed higher levels of harmful bacteria and signs of organ damage. The findings highlight the relative safety of African locust bean compared with some processed or chemically enhanced seasonings, even when consumed at high doses.

According to the researchers, chemical seasonings labelled A and B produced harmful effects on the rodents’ kidneys, heart, and liver, leading to increased inflammation and tissue damage. Fat accumulation in the liver of animals fed these seasonings also raised concerns about a possible link to non-alcoholic fatty liver disease (NAFLD).

While the results suggest that fermented African locust bean could act as a natural modulator of gut health, the scientists caution that the findings were obtained under laboratory conditions in animals.

They therefore recommend further research, including human clinical trials, to better understand how fermented locust bean consumption may influence the gut microbiome and overall health in people.

Long before modern nutritional science emerged, African communities developed dietary traditions that supported digestive health through generations of knowledge. Many traditional African foods contain probiotics, fiber, and nutrients that modern research now recognizes as essential for gut function.

Traditional African diets—often rich in vegetables, whole grains, and fermented foods—align closely with modern nutritional recommendations for maintaining gut health.

Their high fiber content supports regular bowel movements and feeds beneficial bacteria, while fermented foods provide natural probiotics that help maintain healthy intestinal flora. The diversity of plant-based foods also supplies nutrients and phytochemicals that reduce inflammation and strengthen the gut lining.

For example, sorghum porridge is a nutritious breakfast option that supports digestive health. Its slow-digesting carbohydrates provide steady energy without causing blood sugar spikes that can disrupt gut bacteria balance.

Sweet potatoes, widely consumed across Africa, also offer strong digestive benefits. They are rich in fiber, which promotes regular bowel movements, and contain resistant starch that acts as a prebiotic, feeding beneficial gut bacteria. Cooking and cooling sweet potatoes further increases their resistant starch content, enhancing their gut-health benefits.

Cowpeas are another valuable food for digestive health. Their fiber and resistant starch support beneficial gut bacteria and promote a diverse microbial population in the intestines.

In a recent study published in the journal Nature Medicine, researchers found that when people switched from a Western diet to a traditional African diet rich in fiber and fermented foods, they experienced reduced inflammation and improved metabolism within just two weeks.

Because inflammation is linked to many chronic diseases—from Alzheimer’s disease to arthritis—reducing it through diet can have significant health benefits. The study also reported improvements in markers associated with heart disease and type 2 diabetes.

Interestingly, the health benefits of the diet change were still detectable four weeks later, suggesting that the positive effects may be both rapid and long-lasting.

Preserving traditional dietary knowledge not only benefits individual health but also helps maintain cultural heritage. By choosing traditional African foods and preparation methods, people can support digestive wellness while celebrating the continent’s rich culinary traditions.