A growing body of research suggests that a fiber-rich diet may be crucial for maintaining a healthy gut microbiome. According to a recent study published in the journal Nature Microbiology, individuals with higher levels of the beneficial gut bacterium Faecalibacterium tend to have fewer harmful bacteria, such as E. coli.

“Our gut microbiome plays an important role in reducing the growth of potentially harmful bacteria, and it seems this effect may be modulated through diet,” said Alexandre Almeida, the study’s lead researcher and a fellow at Cambridge University, in an interview with NBC News.

The Role of Faecalibacterium

Faecalibacterium thrives on fiber-rich foods, including vegetables, beans, and whole grains. It produces short-chain fatty acids—compounds known to promote gut health. Low levels of these bacteria have been linked to gastrointestinal conditions such as inflammatory bowel disease (IBD).

While the study stops short of proving a direct cause-and-effect relationship between fiber intake and reduced harmful bacteria, the findings add to the mounting evidence of fiber’s health benefits.

The Broader Benefits of Fiber

“There’s solid evidence that fiber helps with diabetes, weight control, and cardiovascular disease,” said Dr. Walter Willett, a professor at the Harvard T.H. Chan School of Public Health and Harvard Medical School. Willett emphasized that adults need approximately 30 grams of fiber daily, yet most Americans consume only about 58% of this recommended amount.

Practical Fiber Swaps

Incorporating more fiber into your diet can be as simple as making a few strategic swaps:

Unsweetened bran cereal (14 g per ½ cup) instead of toasted oat cereal (3 g per cup)

Lima beans (13.2 g per cup) instead of asparagus (2.9 g per cup)

Pumpkin seeds (5.2 g per ounce) instead of hazelnuts (2.8 g per ounce)

Raspberries (8 g per cup) instead of blueberries (3.6 g per cup)

Protecting the Colon

Dr. Daniel Freedberg, a gastroenterologist and associate professor at Columbia University Vagelos College of Physicians and Surgeons, noted that fiber is beneficial for various gastrointestinal conditions, including constipation and diarrhea.

“Fiber is the only thing that is good for both,” Freedberg said. He added that a high-fiber diet might also protect the colon. “In studies where participants were briefly randomized to consume either a very high-fiber diet or an ultraprocessed diet, biopsies revealed not-so-good changes in the colon tissues of those on the ultraprocessed diet.”

The Takeaway

While more research is needed to fully understand the relationship between fiber intake and gut health, the evidence strongly supports the numerous benefits of a high-fiber diet. From improving digestion to reducing the risk of chronic diseases, fiber appears to be a simple yet powerful tool for enhancing overall health. For those looking to improve their gut health, increasing fiber intake through whole, plant-based foods may be an effective first step.