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Side Effects of Glucomannan

author image Jessica Bruso
Based in Massachusetts, Jessica Bruso has been writing since 2008. She holds a master of science degree in food policy and applied nutrition and a bachelor of arts degree in international relations, both from Tufts University.
Side Effects of Glucomannan
While glucomannan may help with weight loss, it does have some potential side effects. Photo Credit Creatas Images/Creatas/Getty Images

Glucomannan, a type of water-soluble fiber that comes mainly from the dried root of the konjac plant, is used by the food industry as a thickener. However, glucomannan supplements are also used for other purposes. For example, they may help you lose weight and lower your blood sugar and cholesterol levels, according to a study published in "The American Journal of Clinical Nutrition" in October 2008. Glucomannan may cause side effects or interfere with certain medications, so check with your doctor before using this supplement.

Gastrointestinal Effects

Side Effects of Glucomannan
Gastrointestinal effects Photo Credit Jupiterimages/Polka Dot/Getty Images

Glucomannan, like other types of soluble fiber, can cause gastrointestinal side effects when you suddenly increase the amount you consume. These can include bloating, stomach pains, loose stools, flatulence and diarrhea. While diarrhea can be a side effect, this doesn't mean glucomannan is effective for treating constipation. A study published in "Clinical Nutrition" in August 2011 found that glucomannan wasn't beneficial for treating functional constipation in children.

Blood Sugar Effects

Side Effects of Glucomannan
Blood test Photo Credit Purestock/Purestock/Getty Images

Soluble fiber, like glucomannan, soaks up water and forms a gel in your digestive tract, which slows down the emptying of the stomach. This slows down the absorption of glucose into the blood and can lower your blood sugar levels. People with diabetes should be careful when using glucommanan to avoid decreasing their blood sugar levels too much.

Choking Risk

Side Effects of Glucomannan
Drink plenty of water with the supplement Photo Credit Creatas Images/Creatas/Getty Images

Don't use glucomannan if you have any blockages in your digestive tract or if you have structural abnormalities in your gut or esophagus. Take this supplement as directed with plenty of water, as there have been incidences of choking when the tablets become lodged in the esophagus and swell.

Potential Medication Interactions

Side Effects of Glucomannan
Potential medication interactions Photo Credit Jupiterimages/Polka Dot/Getty Images

Since glucomannan slows stomach emptying, it may also interfere with certain medications, so only take this supplement either an hour after your other medications or four hours before you take your medications, according to Drugs.com. Glucomannan may also interact with any medications that can lower blood sugar, such as insulin or diabetes medications.

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