Fermented Vegetable Improves Colon Health

A Japanese vegetable fermented with the fungus Aspergillus produces an enzyme associated with improved colon health.

When eaten raw or cooked, burdock root, referred to as gobo in Japan, has little to no positive effects on the colon. However, a prior study found that when gobo was fermented by Aspergillus, rats that consumed the vegetable experienced improved colon health.

In a study presented at the International Conference on Nutraceuticals and Nutrition Supplements, researchers found that the fermentation process produced a protease preparation, a liquid full of different enzymes, that may be the cause of the improvement in colon health.

“Rats that ate a diet supplemented with the protease preparation that was derived from gobo fermented by the fungus Aspergillus had amounts of the bacteria Bifidobacterium in their colons that were several hundred times higher that rats on a non-supplemented diet,” said researcher Norihisa Kato, PhD. “In addition to the microflora improvements, we observed a remarkable improvement of the overall luminal environment of their colons.”

The equivalent amount of the enzyme for an adult to eat would be about 0.1 to 0.4 gram, or 0.04 to 0.16 teaspoons, per day. To have a similar effect with unfermented gobo or dietary fibers, adults would need to consume approximately 5 teaspoons per day.

Bifidobacterium is a common contributor of a healthy intestine, but decreases in numbers as people age. Prior research correlated a boost in Bifidobacterium with greater immune function, improved mental health, and lower rates of bowel disease, which includes colon cancer and colitis.

However, the biological cause of these effects is still unknown, as researchers continue to look for practical methods to increase the amount of the bacteria.

“Bifidobacterium is not normally included in probiotic foods like yogurt because it is so sensitive and not easy to keep alive or grow,” Kato said.

The findings suggest that protease preparation derived from Aspergillus may be a new probiotic with a stronger effect on the colon’s Bifidobacterium compared with other probiotics, such as oligosaccharides and dietary fiber.

“We have completed 3 years of research on fermented gobo and we’re beginning to understand what component of the fermented produce has this beneficial impact on bacteria in the colon,” Kato said. “We’re excited to do more research to reveal how and why Aspergillus-fermented foods and enzymes, especially acid protease derived from Aspergillus, have positive health effects.”