Report on Glucomannan Side Effects and Usage


Natural health supplements sometimes have unexpected side effects or interactions with medication that can lead to adverse reactions that are sometimes life threatening. The following is a list of cautions that you should be aware of before using glucomannan. These are referred to as drug/herb interactions.
Warning 1 – Contraindications: Glucomannan is contraindicated in those who have difficulty in swallowing, intestinal obstruction, and esophageal narrowing. If not taken with adequate amounts of fluid, glucomannan may swell and block the throat, esophagus or intestines. Glucomannan is also contraindicated in those who are hypersensitive to any component of a glucomannan-containing product.

Warning 2 – Pregnancy and breast-feeding: Not enough is known about the affects of glucomannan use during pregnancy and breast-feeding. Stay on the safe side and avoid use.

Warning 3 – All medications: Using glucomannan may decrease the absorption of all medications if taken concurrently. Experts recommend separating dosages by at least 2 hours.

Warning 4 – Antidiabetics: Glucomannan may increase the hypoglycemic effects of oral antidiabetics. Type 2 diabetics who use glucomannan may require adjustment of their antidiabetic medications. Some medications used for diabetes include chlorpropamide (Diabinese), glimepiride (Amaryl), glipizide (Glucotrol), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), tolbutamide (Orinase), and others.

Warning 5 – Antilipidemics: Glucomannan may increase the action of antilipidemics.

Warning 6 – Insulin: Using glucomannan may increase the hypoglycemic effects of insulin.

Warning 7 – Surgery: Glucomannan might interfere with the control of blood sugar during and after surgery. Stop using glucomannan at least 2 weeks before a scheduled surgery.

Warning 8 – Potential health risk warning: A health advisory was released by Health Canada stating the following: “natural health products containing the ingredient glucomannan in tablet, capsule or powder form, which are currently on the Canadian market, have a potential for harm if taken without at least 8 ounces of water or other fluid. The risk to Canadians includes choking and/or blockage of the throat, esophagus or intestine, according to international adverse reaction case reports. It is also important to note that these products should NOT be taken immediately before going to bed.”

Warning 9 – Reduced nutrient warning: This product reduces the absorption of certain vitamins and minerals so it is important to take a multivitamin when using glucomannan.

Used as a natural health remedy: Glucomannan is used internally for the following benefits and conditions:

  • Delays sudden elevation of blood sugar by absorbing it slowly from food.
  • Improves lipid profile and alleviates the fasting blood glucose levels of Type 2 diabetics.
  • May helping control blood sugar in people with type 2 diabetes.
  • Reduces cholesterol by binding to bile acids and carrying them out of the body in the feces. This requires the body to convert more cholesterol into bile acids, which lowers blood cholesterol and other blood fats.
  • Relieves constipation by decreasing fecal transit time.
  • Weight loss aid; promotes feelings of fullness while traveling through the gastrointestinal tract.
  • Weight loss aid; reduces fat absorption.

Side Effects of Glucomannan

While most studies show glucomannan to be well tolerated, there are some possible side effects.

  1. Bloating
  2. Diarrhea
  3. Gas, flatulence
  4. Upset stomach

Because Glucomannan expands when it absorbs liquid, there exists the possibility that the tablet form may get stuck in the throat. Other side effects may also occur when using Glucomannan. (See form below)

As with any herb, a serious allergic reaction is possible. Seek immediate medical attention if you notice any symptoms of a serious allergic reaction. These may include a rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing.

Glucomannan is made from the root of the konjac plant (Amorphophallus konjac).

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