Glucomannan: does it help weight loss?

Glucomannan is a natural, water-soluble dietary fiber extracted from the roots of the elephant yam, konjac plant (Amorphophallus konjac).

Glucomannan is used for constipation, weight loss in adults and children, type 2 diabetes, blood sugar control, and lowering cholesterol.

In foods, glucomannan flour and powder are used as a thickener or gelling agent and as as a food additive — an emulsifier and thickener denoted with the E-number E425-ii.

Glucomannan comprises 40% of the dry weight of the elephant yam, which is originally from Southeast Asia. It has a long history of use in herbal mixtures and traditional foods like tofu, noodles, and konjac jelly.

How Does Glucomannan Help with Weight Loss?

Glucomannan is a water-soluble dietary fiber. It has an exceptional ability to absorb water and is one of the most viscous dietary fibers known.

If you empty a glucomannan capsule into a small glass of water, the entire thing turns into a gel. These unique properties are believed to mediate its effects on weight loss.

Like other soluble fibers, it is believed to promote weight loss via several mechanisms :

  • It has a very low calorie content.
  • It takes up space in the stomach and promotes a feeling of fullness (satiety), reducing food intake at a subsequent meal.
  • It delays emptying of the stomach, contributing to increased satiety.
  • Like other soluble fibers, it reduces the absorption of protein and fat.

slimming

Some studies have shown it protects against fat gain by feeding the friendly bacteria in the intestine, which turn it into short-chain fatty acids like butyrate.

These mechanisms are believed to be similar to the effects of other soluble fibers on weight loss. However, glucomannan is different from other soluble fibers because it’s even more viscous, which makes it particularly effective.

Does it have effect?

There are several randomized controlled trials on glucomannan. In one of them, 176 healthy overweight people, were randomly assigned to ingest a supplement with glucomannan, or placebo (a dummy pill), while on a calorie-restricted diet. Results showed that weight loss was significantly greater in the glucomannan groups.

There are several other studies that agree with this. Glucomannan causes modest weight loss in overweight and obese individuals when regularly ingested before a meal.

It is especially effective when combined with a weight-reducing diet. The same applies to all weight-loss methods – they work best in combination.

Other health benefits

Glucomannan provides other health benefits like:

  • Lower total cholesterol
  • Lower LDL cholesterol .
  • Lower triglycerides
  • Fasting blood sugar

The main mechanism by which it reduces blood cholesterol is by decreasing absorption of cholesterol in the gut.

According to scientific results from few studies, adding glucomannan to your diet could potentially lower the risk of developing heart disease and type 2 diabetes.

How to take it?

For weight loss, a dosage of 1 gram, 3 times per day is considered sufficient.

In contact with water, glucomannan expands and can absorb up to 50 times its weight. Therefore, the recommended dosage of glucomannan is lower compared to other fiber supplements.

But, it does not have any effect on weight loss unless it is taken before a meal. Timing recommendations range from 15 minutes to 1 hour before a meal.

Does it have side effects?

Glucomannan is well tolerated and is generally considered safe.

If accidentally the capsule of glucomannan expands before reaching the stomach, it may cause choking or blockage of the throat and esophagus (the tube that moves food from your mouth to your stomach). To prevent this, it should be washed down with 1-2 glasses of water or other liquid.

Some people may experience mild side effects, such as bloating, flatulence, soft stools or diarrhea, but this is usually uncommon.

Glucomannan can also reduce the absorption of oral medications like sulfonylurea, a diabetes drug. This can be avoided by taking the medication at least 4 hours after or one hour before ingesting glucomannan.

Should you be taking it?

According to the evidence, glucomannan is an effective weight-loss supplement. But same as with pretty much any weight-loss strategy, it doesn’t work in isolation.

The only known way to lose weight in the long-term, is to make a permanent change to your lifestyle.

Glucomannan may help make that easier, but it won’t work any miracles on its own.

Sources:

  • Sood N, Baker WL, Coleman CI, Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis, Am J Clin Nutr. 2008 Oct;88(4):1167-75.
  • Keithley J, Swanson B, Glucomannan and obesity: a critical review, Altern Ther Health Med. 2005 Nov-Dec;11(6):30-4.
  • Sood N, Baker WL, Coleman CI, Effect of glucomannan on plasma lipid and glucose concentrations, body weight, and blood pressure: systematic review and meta-analysis, Am J Clin Nutr. 2008 Oct;88(4):1167-75.
  • Walsh DE, Yaghoubian V, Behforooz A, Effect of glucomannan on obese patients: a clinical study, Int J Obes. 1984;8(4):289-93.
  • Keithley J, Swanson B, Glucomannan and obesity: a critical review, Altern Ther Health Med. 2005 Nov-Dec;11(6):30-4.
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s