Bulk (or bulking) laxatives are products that relieve constipation. Bulk laxatives are comprised of fiber that adds heft to and draws water into the stool. This softer, larger stool stimulates the intestines, producing a bowel movement. Bulk laxatives are generally available over the counter. Remember that it is very important to drink plenty of fluids when using bulk laxatives to avoid obstructions within the esophagus or colon. Here is an overview of the main types of bulk laxatives:
Psyllium
Psyllium, also known as Isphagula, is a natural (plant-based) form of soluble fiber. Psyllium is sold under a variety of brand names, including:
- Fiberall
- Genfiber
- Konsyl
- Metamucil
Intestinal bacteria interact with the natural fiber found within psyllium, increasing the risk for symptoms of gas and bloating. In rare cases, an individual may experience a severe allergic reaction to psyllium.
Calcium Polycarbophil
Calcium polycarbophil is a synthetic form of fiber. In contrast to psyllium, calcium polycarbophil runs less of a risk of interacting with gut bacteria and producing unwanted gas. Calcium polycarbophil is found in the following products:
Methylcellulose
Citrucel is the only product that contains methylcellulose. Methylcellulose contains both synthetic and natural fiber. It is also resistant to action by intestinal bacteria.
Do Bulk Laxatives Work?
According to a review by the American College of Gastroenterology (ACG) there are not a lot of well-run, conclusive studies regarding the safety and effectiveness of bulk laxatives. There is some research support that psyllium increases stool frequency in patients who suffer from chronic constipation. A separate research study compared psyllium and bran as a treatment for IBS. That study found that psyllium was more effective in reducing IBS symptoms and that bran was more likely to cause unwanted side effects.
The Bottom Line
If you are thinking about using a bulk laxative, psyllium seems to hold the highest promise in terms of effectiveness. Whether you choose psyllium or one of the other types of bulk laxatives, be sure to drink plenty of water! And don't forget to add more high fiber foods to your daily diet.
For more laxative options:
Sources:
American College of Gastroenterology Chronic Constipation Task Force "An Evidence-Based Approach to the Management of Chronic Constipation in North America" The American Journal of Gastroenterology 2005 100:S1-S4.
Bijkerk, C., Wit, N., Muris, J., Whorwell, P., Knottnerus, J. & Hoes, A. "Soluble or insoluble fibre in irritable bowel syndrome in primary care? Randomised placebo controlled trial" Britsh Medical Journal 2009 339:b3145.
Lembo, A. & Camilleri, M. "Chronic Constipation" The New England Journal of Medicine 2003 349:1360-1368.
