Eating more fiber, found in whole grains, vegetables and fruits, could help protect us against dangerous bacteria in the intestine. After analyzing samples of the gut microbiomes of more than 12,000 people from 45 countries, researchers determined that those tested with high levels of a certain type of beneficial bacteria known as Faecalibacterium were more likely to have low levels of potentially deadly bacteria such as E. coli, according to the report published this month in Nature Microbiology.
The researchers also found that samples with high levels of Faecalibacterium had high levels of beneficial compounds called short-chain fatty acids, which are a byproduct of the breakdown of fiber. Research has indicated that having reduced levels of these types of bacteria is linked to inflammatory bowel or gastrointestinal conditions.
“The main conclusion of the study is that our gut microbiome plays an important role in reducing the growth of potentially harmful bacteria in our gut, and it appears that this effect can be modulated through diet,” he told NBC News in an email. email the principal investigator of the study, Alexandre Almeida, a researcher at the University of Cambridge.
The gut microbiome is a collection of microbes including bacteria, fungi, and viruses that inhabit the gastrointestinal tract. Gut microbiomes vary from person to person.
The new findings suggest that eating high-fiber foods, such as vegetables, beans and grains, could help protect against harmful bacteria, he added.
Almeida cautioned that the new study does not prove that fiber protects against harmful bacteria. “This was an observational study conducted on people’s gut microbiome at one point in time, so we need to keep in mind that most of our results are based on associations,” he said. “This means that future work is needed to experimentally test whether certain things like fiber and other nutrients prevent the incidence of infections over a longer period of time.”
Using stool samples from 65 studies in 45 countries, scientists analyzed the bacterial composition of 12,238 people. They found that the composition of a person’s microbiome could predict whether the person’s gut was likely to be invaded by harmful bacteria.
“This is an impressive analysis,” said Dr. Walter Willett, professor of epidemiology and nutrition at the Harvard TH Chan School of Public Health and professor of medicine at Harvard Medical School in Boston, who noted that it does not prove that Fiber affects a person’s susceptibility to harmful bacteria. “It’s a small piece of the puzzle. In the future it will be essential to include diet in the analysis.”
There are many other reasons to consume the recommended amounts of fiber, Willett said. “There is really strong evidence that fiber helps with diabetes, weight management and cardiovascular disease.”
Adults need 30 grams of fiber a day, Willett said.
According to research from the United States Department of Agriculture, most Americans consume only 58% of that daily amount.
“But it’s not practical to count grams,” Willett said. “The easiest thing is to follow a couple of rules: whenever you eat cereals, make sure they are whole grains and eat a variety of fruits and vegetables. “That alone will get you a lot of fiber.”
Certain foods are especially rich in fiber.
For example:
- Unsweetened bran cereals (14 grams per half cup) compared to toasted oat cereals (3 grams per cup)
- Broad beans (13.2 grams per cup) compared to asparagus (2.9 grams per cup)
- Pumpkin seeds (5.2 grams per ounce) versus hazelnuts (2.8 grams per ounce)
- Raspberries (8 grams per cup) vs. blueberries (3.6 g per cup)
“We don’t know from this study whether eating more fiber will result in the production of more beneficial bacteria,” said Dr. Daniel Freedberg, a gastroenterologist and associate professor of medicine and epidemiology at Columbia University Vagelos College of Physicians and Surgeons. in New York City. “But there is a lot of evidence to suggest that we eat too little fiber.”
Increasing fiber intake would certainly be good for people who don’t consume enough.
“I see people with gastrointestinal conditions like constipation and diarrhea, and fiber is the only thing that’s good for both,” Freedberg added.
A diet rich in fiber may protect the colon, he added.
“There are some studies where people were randomly assigned to eat a very, very high-fiber diet or an ultra-processed diet,” Freedberg said. “In their biopsies, you can see not-so-good changes in the colon tissues of people who ate ultra-processed foods.”