Shiitake mushrooms demonstrate potent antimicrobial effects

In the U.S., salmonella is the leading cause of food-related outbreaks. There are antibiotics available to treat foodborne illness, but these cause harmful side effects. In fact, certain bacteria have become resistant to these drugs. So, a team of researchers from South Korea and the U.S. developed a novel antimicrobial food-compatible formulation to fight these bacteria.

In thier study, published in the journal BMC Complementary and Alternative Medicine, the research team developed a formulation by fermenting shiitake mushroom with rice bran. Fermented shiitake mushroom with rice bran can inhibit the growth of Salmonella typhimurium in infected mouse organs, suggesting that they can be used as a functional antimicrobial food and natural antibiotic.

For the study, the researchers examined the effect of the formulation of fermented shiitake mushroom with added rice bran in murine macrophage cells and in mice. Rice plants produce bioactive rice brans and hulls, while mushrooms produce bioactive polysaccharides and other compounds. These food components have been shown to have numerous potential health benefits in cells, rodents, and humans.

When the researchers fermented shiitake mushroom mycelia with rice bran, these foods produced bioactive compounds that are not present in the same combination of mycelia and rice bran that was not fermented. The extracts of the product inhibited the growth of S. typhimurium in infected macrophage cells and in different mouse organs, such as cecum, mesenteric lymph node, spleen, and liver. They also promoted the uptake of the bacteria into macrophage cells, as well as the increase of protein expressions that induced bacterial destruction in autolysosomes of RAW 264.7 cells. In addition, treatment with the extracts also induced increased excretion of bacteria in feces and their decreased translocation to internal organs.

From these findings, the researchers concluded that fermented shiitake mushroom mycelia with rice bran could be used as a functional antimicrobial food and a natural antibiotic.

More on shiitake mushrooms and its many health benefits

Shiitake mushrooms are brown-capped mushrooms that are native to China, Japan, and Korea. Today, they are the second most cultivated mushrooms in the world. They can grow on trees like beech, chestnut, and maple in hot and humid climates. They are used as supplements because of their promising health benefits, such as:

  • Supporting heart health: Shiitake mushrooms keep the heart healthy in different ways. They contain compounds that help lower high cholesterol and may prevent plaque from sticking to artery walls, namely eritadenine, sterols, and beta-glucans. An animal study also found that treating rats that genetically have high blood pressure with shiitake mushroom powder prevented an increase in blood pressure. Another study also reported that rats fed with a high-fat diet and given shiitake mushrooms developed less fat in their livers, less plaque on their artery walls, and had lower cholesterol levels compared to those that did not receive any mushroom supplement. (Related: Shiitake mushrooms help fight cancer, reduce cholesterol, and boost immunity.)
  • Strengthening the immune system: Shiitake mushrooms can also strengthen your immune system. In one study, researchers fed people with around two dried shiitakes every day for a month. After the treatment period, the participants experienced less inflammation and their immune markers improved. The researchers explained that this may be due to the polysaccharides found in shiitake mushrooms. An animal study also found that supplementing with shiitake mushrooms helped reduce age-related decline in immune function.
  • Warding off cancer: Research has also shown that polysaccharides in shiitake mushrooms may also have cancer-fighting effects. One of these polysaccharides is lentinan, which has been found to fight tumors by activating the immune system and suppressing the growth and spread of leukemia cells.

Aside from taking shiitake mushrooms as supplements, you can also use them — raw or dried — in many dishes. These mushrooms are also a great addition to your diet because they are low in calories and provide good amounts of fiber, B vitamins, and some minerals like selenium, manganese, and zinc.

Learn more about functional foods like shiitake mushrooms and rice bran by visiting

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