How Fiber Promotes Digestive Health and Lowers Your Cholesterol

For many intestinal health conditions, fiber may be the answer

By Roberta H. Anding, MS, Baylor College of Medicine and Texas Children’s Hospital
Edited by Kate Findley and proofread by Angela Shoemaker, Wondrium Daily

Many Americans struggle with digestive conditions, such as irritable bowel syndrome (IBS). Thankfully, fiber can help with these conditions, while also giving other health benefits. Professor Anding explains.

Foods high in fiber
Insoluble fiber and soluble fiber achieve a balance in your digestive tract, while soluble fiber also lowers cholesterol and blood sugar levels. Photo By Tatjana Baibakova / Shutterstock

Digestive Disease and Fiber

Fiber can be used to treat or prevent a wide range of digestive diseases or conditions. In the United States, the prevalence of IBS, alternating constipation and diarrhea, can be based on the fact that your gut is not moving as seamlessly as it needs to be. To treat IBS, you need to make sure that you consume adequate amounts of both soluble and insoluble fiber.

Insoluble fiber is best for treating constipation and can be found in wheat bran, many vegetables, nuts, and celery. Soluble fiber is an effective remedy for diarrhea and can be found in pears, bananas, apples, citrus fruits, and carrots.

Diverticular disease occurs when the gut forms little pouches around the wall of the large intestine (colon) from the straining to have a bowel movement, which can lead to fever and abdominal pain. Many scientists recommend increasing the amount of fiber that you have in your diet, which again reduces constipation and the resulting complications, including diverticular disease.

Healthy for the Long Haul

In countries where people regularly consume large amounts of fiber, there is little digestive disease. By contrast, digestive disease is higher in countries like the United States where people, on average, consume diets that are lower in fiber. When people are afflicted with these conditions, they often turn to supplements for the answer.

“Keep in mind that in the United States, we’re always looking for a quick fix to a problem,” Professor Anding said. “I’ll remind you over and over again that your body remembers what you do most of the time; so if, most of the time, you’re trying to promote adequate amounts of fiber, you can help to prevent things from happening.” 

According to Professor Anding, if you are diagnosed with diverticular disease or IBS, your strategy to solve the problem should not include significantly increasing your fiber intake by taking a supplement. Instead, you should improve your diet on a holistic level and accept that the changes you are seeking may come gradually.

Fiber and Cholesterol

In addition to preventing or treating digestive disorders, fiber can also help to lower blood cholesterol which in turn helps to prevent cardiovascular (heart) disease. Soluble fiber—those gumming, gelling fibers in beans and oats, flaxseed, and oat bran—can actually help to lower LDL

“LDL” stands for low-density lipoprotein and oftentimes gets labeled the “bad guy.” It’s the kind of cholesterol that adheres to arterial walls, narrowing blood flow. 

Soluble fiber can lower LDL by binding with bile—which is about 70% to 75% cholesterol—and it prevents the bile from being normally reabsorbed. Normally, when bile is released from your gallbladder in response to a fatty meal, it helps to emulsify the fat, keeps the oil and water mixed together, and gets recycled in the large intestine. 

In the presence of water-soluble fiber, the bile sticks to the fiber, and the fiber causes it to be released or eliminated when you have a bowel movement. What does the body do? It has to make more bile. 

Where does it get the raw materials? It gets the raw materials from your blood cholesterol. Thus, water-soluble fiber works as an aid in terms of keeping your cholesterol lower.

Other Fiber Benefits

Water-soluble fibers, in particular, also can help to control blood sugar levels. For people with metabolic syndrome—which is thought of as pre-diabetes—it can improve blood sugar by slowly controlling the absorption of sugar. 

It delays the entry of that food into your blood supply, which lowers the glycemic index (GI)—the ranking of foods according to how fast they cause blood sugars to rise. Foods containing mostly soluble fibers, then, tend to have lower GIs.

Overall, then, fiber carries many benefits. It can help prevent digestive diseases, lowers cholesterol, and lowers blood sugar.

This article was edited by Kate Findley, Writer for Wondrium Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for Wondrium Daily.

Professor Roberta H. Anding is a registered dietitian and Director of Sports Nutrition and a clinical dietitian at Baylor College of Medicine and Texas Children’s Hospital. She also teaches and lectures in the Baylor College of Medicine’s Department of Pediatrics, Section of Adolescent Medicine and Sports Medicine, and in the Department of Kinesiology at Rice University.