Bowel Health and Beyond: How Dietary Fiber Provides Many Surprising Benefits

Most people understand that consuming dietary fiber – particularly in fruits, vegetables, beans, legumes, nuts, seeds and whole grains -- helps keep the digestive tract flowing and bowel movements regular.

But there a many other benefits to fiber-rich diets that extend to overall heart health, blood sugar control, weight management, and a better functioning gut microbiome, which helps keep unhealthy bacteria in check. Clinical studies continue to find that the health of the gut microbiome plays a key role beyond our digestive system and may affect conditions including diabetes, obesity, heart disease and cancer. (March is National Nutrition Month.)

“It's a topic many people are bashful about,” explains Lucette Talamas, a registered dietitian with Community Health at Baptist Health South Florida. “But in nutrition and dietetics, we're not bashful about asking: ‘Are you regular? How often do you use the restroom as far as pooping?’ There’s no other way to say it. Fiber prevents constipation, which is something that affects a lot of people -- children, elderly, people that are doing diets that cut carbs. And that means they also cut their fruits and whole grains, and then they get constipated.”

Public health officials estimate that less than 10 percent of U.S. adults are consuming the recommended amounts of daily dietary fiber -- 25 grams of fiber per day for women and 38 grams for men.

Lucette Talamas, RD, a registered dietitian with Community Health at Baptist Health South Florida.

Fiber is an indigestible carbohydrate that comes from plant-based foods. Balanced, mostly plant-based diets are considered the healthiest. The Mediterranean Diet, promoted widely by nutrition and medical experts, earned the title of best overall diet for the seventh consecutive year, according to the new 2024 ratings from U.S. News & World Report. 

The Mediterranean diet is as a primarily plant-based eating plan that includes whole grains, olive oil and healthy fats, fruits, vegetables, beans and other legumes, nuts, herbs, and spices. Meat and dairy are eaten in smaller quantities, with the preferred animal protein being fish and seafood, followed by poultry. Red meat is eaten infrequently.

Fiber helps speed up the elimination of toxic waste through the colon. “Fiber acts like a scrub brush, cleaning your digestive tract,” states the U.S. Centers for Disease Control and Prevention (CDC). “It helps clean out bacteria and other buildup to improve gut health and help reduce your risk of colon cancer.”

Fiber can also help you reach and maintain a healthy weight. Fiber also promotes healthy cholesterol levels, a cornerstone for heart health. Fiber prevents the body from taking in some fat and cholesterol, lowering triglyceride and cholesterol levels to help reduce the risk of heart disease. All of these fiber benefits come primarily from whole foods, not over-the-counter pill supplements, dietitians say.

“Prebiotic is a type of fiber found from food,” said Ms. Talamas. “While you're eating the fiber that you know is helping your cholesterol, you're also feeding your probiotics in your gut. You're also helping maintain a healthy colon and promoting regular bowel habits.”

Dietary fiber provides another key advantage when it comes to weight management. Fiber slows the rate of digestion, which makes someone feel fuller and reduce cravings. Because the body is unable to absorb and break down fiber, it doesn’t cause a spike in blood sugar the way other carbohydrates can. This can help individuals who have prediabetes or diabetes keep blood sugar levels in their target range.

“Meals providing meaningful sources of dietary fiber tend to be processed more slowly by the body,” said Ms. Talamas. “That also relates to the point about blood sugar management. Slower digestion of high fiber foods contributes to a lower blood sugar spike while providing more satiety. Fruits and vegetables, for example, are high-volume food with lower calories.

“If you're a visual eater and you like to eat a large plate of food, then you’re eating a higher volume of food with more fiber if half of that plate is vegetables. At the end of the day, it helps promote a feeling of fullness with fewer calories, which is a very important aspect of managing our weight and eating healthy.”