Dietary Fiber for Constipation

Medically Reviewed by Christine Mikstas, RD, LD on February 14, 2023
3 min read

Can food be medicine? Sometimes, yes. It's becoming clear in recent years that what you eat can be highly effective in preventing or reversing some health problems, especially chronic constipation.

Constipation is a symptom, not a disease. There are some serious medical conditions that can cause chronic constipation. Make sure you see your doctor for a medical evaluation. If you are healthy and looking for safe and effective long-term relief for chronic constipation, you might find help on your grocer's shelves. Hundreds of foods and plant-based fiber products are available to relieve constipation -- naturally.

Dietary fiber refers to the edible parts of plants or carbohydrates that cannot be digested. Fiber is in all plant foods, including fruits, vegetables, grains, nuts, seeds, and legumes. You can also find a form of fiber called chitin in the shells of crustaceans such as crab, lobster, and shrimp.

Soluble fiber partly dissolves in water, creating a gel-like substance that helps lower cholesterol. Sources of soluble fiber include oats, barley, rye, beans, oranges, and apples.

Insoluble fiber remains more intact as it passes through the digestive system. That makes insoluble fiber especially helpful in preventing or easing constipation. Insoluble fiber may also help with weight loss by making meals seem more filling without adding calories. Sources of insoluble fiber include wheat, brown rice, celery, carrots, nuts, and seeds.

Foods can contain both soluble and insoluble fiber.

Which type of fiber is better to ease constipation? Go for whole-grain breads, cereals, and pastas. Cereal fibers generally have cell walls that resist digestion and retain water within the cellular structures. Wheat bran can be highly effective as a natural laxative.

Eat plenty of fresh fruits, vegetables, and legumes such as beans and lentils. The fiber found in citrus fruits and legumes stimulates the growth of colonic flora, which increases the stool weight and the amount of bacteria in the stool. Encouraging the growth of certain bacteria in the colon may help promote a healthy intestine.

According to the USDA’s Dietary Guidelines for Americans, 2020-2025, more than 90% of women and 97% of men do not meet recommended intakes for dietary fiber. Women younger than 51 should aim for 25 grams of fiber daily. Men younger than 51 should aim for 38 grams of fiber daily. Women 51 and older should get 21 grams of fiber daily. Men 51 and older should get 30 grams daily. 

For adults, the Dietary Guidelines for Americans, 2020-2025 recommends between 2 and 4 cups of vegetables and 1.5 and 2.5 cups of fruit daily depending on the total number of calories needed in a day. Fiber-rich fruits and vegetables include apples, oranges, broccoli, berries, pears, peas, figs, carrots, and beans. Some people get stomach cramps and gas when they increase their intake of fiber. Change your diet gradually and increase fluids to reduce discomfort.

Prunes contain sorbitol, which has a natural, laxative effect in the body. Prunes (which are just dried plums) are also high in disease-fighting antioxidants and have both insoluble and soluble fiber. One cup of pitted, uncooked prunes contains 12 grams of fiber. Three dried plums have 2 grams of fiber.

It's best to get fiber from food. But if you can't eat enough fruits and vegetables to make a difference, try foods that contain psyllium seed husk, bran, and methylcellulose. If that’s still not working, then opt for fiber supplements. Examples include psyllium, methylcellulose, wheat dextrin, and calcium polycarbophil. With psyllium powder, mix the powder in a glass of water one to three times daily. Fiber must have water in order to sweep the colon and move the stool out of your body. Be sure to drink enough water along with this psyllium powder drink. The drink may cause you to feel bloated until you get used to the fiber.

A high-fiber diet ends chronic constipation for many people. But those who have slow transit or pelvic floor dysfunction may respond poorly to increased dietary fiber. If you have a change in frequency of bowel movements and develop acute constipation, talk to your doctor. The constipation could be caused by an underlying medical condition.