Mulberry’s potential benefits may begin with gut microbes, but the way it is prepared could make all the difference.
Researchers are examining whether bioactive compounds in mulberry can alter the gut microbiota in ways that influence glucose regulation, fat metabolism, and intestinal health.
A review involving scientists from Wroclaw Medical University found encouraging evidence from laboratory and animal studies, although research in humans remains limited.
Why Mulberry Preparations Differ
The gut microbiota helps digest food, maintain the intestinal environment, and produce substances that can affect the rest of the body. Anna Prescha, PhD, DSc, a professor in the Department of Dietetics and Bromatology at Wroclaw Medical University, says mulberry is especially interesting because it contains polyphenols and polysaccharides that may interact with these microorganisms.
Most research has examined white mulberry (Morus alba), but black mulberry (Morus nigra), particularly its fruit, has also shown potential. Mulberry leaves contain polyphenols, polysaccharides, and 1-deoxynojirimycin (DNJ), which is known to influence carbohydrate metabolism. Black mulberry fruit supplies abundant anthocyanins and other phenolic compounds, as well as polysaccharides.
The final product depends heavily on how the plant material is handled. Drying, fermentation, and extraction can change both the quantity and balance of its active compounds. Two preparations made from the same leaves or fruit may therefore have different compositions and produce different biological responses.
Gut Bacteria Turn Mulberry Into Metabolites
Studies reviewed by the researchers suggest that preparations made from mulberry leaves and fruit can alter the abundance and activity of certain gut bacteria. Some experiments reported increases in beneficial microbes and greater production of acetate, propionate, and butyrate.
These short-chain fatty acids are created when gut bacteria ferment dietary material. They help support the intestinal lining and contribute to the chemical communication connecting the gut with metabolism elsewhere in the body. Several studies linked mulberry-related microbial changes with improvements in measures of glucose and lipid metabolism.
The effects, however, varied considerably among preparations. Polysaccharides extracted from black mulberry fruit differed in structure and in how effectively gut microbes used them. Fractions obtained through water extraction and treatment with pectate lyase displayed the greatest prebiotic potential.
Structure Shapes the Microbial Response
Leaf polysaccharides showed the same sensitivity to chemical structure. Features such as molecular weight and monosaccharide composition appeared to influence which bacteria could consume them and which short-chain fatty acids those microbes produced. This helps explain why simply listing the compounds in a product may not be enough to predict its effects.
Some of the strongest results came from mixtures rather than isolated components. In mice fed a high-fat diet, a white mulberry fruit fraction containing both polyphenols and polysaccharides produced more favorable changes in the gut microbiota than either fraction given separately. The combined treatment also improved some indicators of metabolic syndrome and intestinal health.
Researchers then transferred microbiota from mice treated with the combined fraction into other animals. The recipient mice also experienced improvements in certain metabolic disturbances, strengthening the possibility that the altered microbial community helped transmit some of the treatment’s effects.
Finding the Right Mulberry Formula
The findings suggest that mulberry’s biological activity may emerge from interactions among multiple compounds rather than from one dominant ingredient. Prescha emphasizes that researchers must consider the species, plant part, chemical proportions, and processing method when trying to produce a specific effect. A universal mulberry supplement is therefore less realistic than carefully designed preparations intended for particular purposes.
The review began with the Nutri-Sfera Student Research Group in the Department of Dietetics and Bromatology at Wroclaw Medical University. The topic was proposed by two students who have since graduated: Marta Miszczak from the Dietetics program and Karolina Kłosowska-Buryło from the Pharmacy program. Their involvement brought nutritional and pharmaceutical perspectives together, allowing the team to examine mulberry as both a complex plant material and a possible influence on the microbiota and metabolism.
Human Evidence Is Still Missing
Despite the encouraging results, most evidence comes from animal models and in vitro experiments. Human studies directly measuring how mulberry preparations affect the gut microbiota remain scarce. Comparisons are also difficult because relatively few studies provide a detailed chemical analysis of the products they test.
Prescha cautions that researchers cannot yet assume the relationships observed among mulberry, gut microbes, and metabolism will work the same way in people. Changes found in mice or laboratory cultures may not translate into meaningful human health benefits.
Clinical trials will need to test standardized preparations whose chemical composition has been thoroughly documented. These studies could determine which mulberry products alter the human gut microbiota, how large and consistent those changes are, and whether they lead to measurable improvements in metabolic or intestinal health.
Reference: “Mulberry, Gut Microbiota and Gut Functionality: Effects Shaped by Raw Material and Processing Methods” by Marta Maria Miszczak, Karolina Kłosowska-Buryło, Joanna Magdalena Pieczyńska, Monika Bielecka and Anna Prescha, 29 June 2026, Biomolecules.
DOI: 10.3390/biom16070965
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