Consuming ample amounts of fiber each day does more than stave off constipation. It can also lower your blood sugar levels and reduce your chances of developing heart disease, both of which are important if you have diabetes or are at risk for developing it.
But can you get enough fiber through foods such as whole grains, fruits, vegetables and legumes, or do you need to take a supplement such as Metamucil? Experts say there's a role for both.
Read more: 19 High-Fiber Foods — Some May Surprise You!
Diabetes and Fiber
Diabetes occurs when your body either no longer produces insulin or can no longer use it efficiently. Insulin is a hormone that allows your body to use sugar (glucose) from carbohydrates for energy.
When insulin can't do its job, glucose can build up in your bloodstream and set the stage for diabetes and its related complications, the American Diabetes Association explains. Type 2 diabetes, the form of the disease most closely linked to obesity, can sometimes be controlled with lifestyle changes, including maintaining a normal weight, eating a healthful diet and engaging in regular exercise, according to experts at the Harvard Health Publishing.
Fiber needs to be part of this healthful diet. Found in whole grains, fruits, vegetables, quinoa, oatmeal, dried beans, lentils, nuts and seeds, fiber makes you feel full faster and for longer, which promotes a healthy weight, the Academy of Nutrition and Dietetics points out. Women should aim for 25 grams of fiber a day, while men need 38 grams, according to the Academy of Nutrition and Dietetics.
Getting fiber from food is recommended for people with diabetes, says Audrey Koltun, RDN, a dietitian in the Division of Pediatric Endocrinology at Cohen Children's Medical Center in Lake Success, New York. Soluble fiber slows the absorption of sugar, which can improve blood sugar levels, the Mayo Clinic says. Soluble fiber, which dissolves in water, is found in oats, peas, beans, apples and psyllium. A fiber-rich diet may also reduce the risk of developing Type 2 diabetes.
People with diabetes are at higher risk for heart disease. Soluble fiber reduces low-density lipoprotein (LDL), known as the "bad" cholesterol, and high cholesterol is a major risk factor for heart disease.
Fiber may also reduce blood pressure and inflammation, further lowering heart disease risk, according to the Mayo Clinic.
What About Supplements?
Fiber supplements, such as Metamucil, may play a role in helping certain people with diabetes get enough fiber, especially if they are constipated, Koltun says.
"Metamucil is made from [a fiber called] psyllium husk, which slows down the absorption of glucose and can cause less of a spike in blood sugar," she says. But "this does not mean someone with diabetes who eats a high-carbohydrate/high-sugar diet can expect normal blood sugars after taking Metamucil."
Dana Greene, RD, a dietitian in Brookline, Massachusetts, says she suggests fiber supplements like Metamucil to patients with diabetes when they can't get what they need through diet, describing supplements as "a good backup plan."
Supplements are also lower in calories and carbs than foods, which are important aspects of meal planning for people with diabetes, she adds. There may be some additional benefits to fiber supplements, too. A review of 28 clinical trials that included 1,394 people with diabetes found that those who took soluble fiber supplements had slightly lower blood sugar levels than their counterparts who didn't take fiber supplements.
The research, published in the May 2019 issue of Diabetes Care, also found that people who took about 13 grams (about 1 tablespoon) of fiber daily for up to a year had lower levels of hemoglobin A1c, a snapshot of blood sugar over time, and they also had lower blood sugar levels on an empty stomach (fasting glucose levels).
Bottom Line on Fiber
Slow and steady always wins the race, especially when it comes to increasing your fiber intake, Greene says. Upping your fiber intake too quickly with supplements may cause gas, bloating, diarrhea or constipation, she warns, adding that it's also important to drink enough water, which helps fiber move through your body.
Finally, she notes that it's always a good idea to talk to your doctor or a dietitian about any changes to your diet.
Read more: Can You Eat Too Much Metamucil?
Is This an Emergency?
- American Diabetes Association: “Blood Sugar and Insulin at Work”
- Harvard Health Publishing: “Healthy Lifestyle Can Prevent Diabetes (and Even Reverse It)”
- Academy of Nutrition and Dietetics: “Easy Ways to Boost Fiber in Your Daily Diet”
- Audrey Koltun, RDN, CDE, CDN, registered dietitian/nutritionist and certified diabetes educator, Division of Pediatric Endocrinology, Cohen Children’s Medical Center, Lake Success, New York
- Mayo Clinic: “Nutrition and Healthy Eating”
- Dana Greene, RD, dietitian, Brookline, Massachusetts
- Diabetes Care: “Should Viscous Fiber Supplements Be Considered in Diabetes Control? Results From a Systematic Review and Meta-Analysis of Randomized Controlled Trials”