Eating more fiber from whole grains, vegetables, and fruits may help prevent dangerous bacteria in your gut.
After analyzing gut microbiome samples from more than 12,000 people from 45 countries, researchers determined that people with high levels of a certain type of beneficial bacteria called Faecalibacterium are more likely to have low levels of potentially deadly bacteria, E. coli, for example, according to a report published this month in Nature Microbiology .
The researchers also found that samples with high levels of Faecalibacterium contained high levels of beneficial compounds called short-chain fatty acids, which are byproducts of the breakdown of fiber. Research shows that reduced levels of these bacteria are associated with inflammatory bowel or gastrointestinal disease.
"The main conclusion of our study is that our gut microbiota plays an important role in reducing the growth of potentially harmful bacteria in the gut, and that this effect appears to be modulated by diet," said Alexander Armey, lead researcher on the study Alexandre Almeida said. The University of Cambridge researcher told NBC News in an email.
The gut microbiota is the collection of microorganisms that live in the gastrointestinal tract, including bacteria, fungi, and viruses. Gut microbiota vary from person to person.
New findings suggest that eating high-fiber foods such as vegetables, legumes and grains may help protect against harmful bacteria, he added.
Almeida warned that the new research doesn't prove that fiber protects against harmful bacteria. "This is an observational study of people's gut microbiomes at one point in time, so we need to be aware that most of our results are based on associations," he said. "This means that future experiments are needed to test whether certain substances, such as fiber and other nutrients, can prevent the onset of infection over a longer period of time."
The scientists analyzed the bacterial composition of 12,238 people using stool samples from 65 studies in 45 countries. They found that the composition of a person's microbiome can predict whether that person's gut is likely to be filled with harmful bacteria.
"This is an impressive analysis," said Dr. Walter Willett, professor of epidemiology and nutrition at the Harvard T.H. Chan School of Public Health and professor of medicine at Harvard Medical School in Boston. He noted that it does not prove it. Fiber affects a person's susceptibility to harmful bacteria. "This is just one piece of the puzzle. In the future, incorporating diet into analyzes will be critical."
Willett says there are many other reasons to consume the recommended amounts of fiber. “There is really good evidence that fiber can help with diabetes, weight management and cardiovascular disease.”
Willett says adults need 30 grams of fiber per day.
According to USDA research, most Americans only get about 58% of their daily intake.
"But counting grams is impractical," Willett said. "The simplest thing is to follow a few rules: Whenever you eat grains, make sure they are whole grains, and eat a variety of fruits and vegetables. Just do this and you'll get plenty of fiber."
Certain foods are particularly high in fiber.
For example:
"We don't know from this study that eating more fiber will lead to more beneficial bacteria," said Daniel Fernando, a gastroenterologist and associate professor of medicine and epidemiology at Columbia University Vagelos College of Physicians and Surgeons in New York City. Dr. Rydberg said the city. "But there's a lot of evidence that we really are eating too little fiber."
Of course, increasing fiber intake can be beneficial for those who don't get enough.
"I see people with gastrointestinal issues like constipation and diarrhea, and fiber is the only thing that's good for both," Friedberg said.
He added that a high-fiber diet may protect the colon.
"In some studies, people are simply randomized into either a very, very high-fiber diet or an ultra-processed diet," Friedberg said. "In their biopsies, you can see that in people who eat ultra-processed foods, There were not-so-good changes in the colon tissue.”