Glucomannan is a water-soluble dietary fiber. It is often used as an emulsifier and thickener, due to its high water absorption (glucomannan can absorb 50 times its weight in water).
Products containing glucomannan have been marketed as weight loss supplements for years now. And while there has been some evidence that it does help with weight loss, there have been no large, long-term studies with conclusive results.
The most popular non-supplemental product on the market that contains glucomannan fiber are the famous shirataki noodles. Made from konjac yam, shirataki noodles have been nicknamed ‘miraculous’ noodles due to their low-calorie (less than 5 calories per serving), low-carb (less than 1 per serving), 0 fat content.
Despite the lack of long-term studies on supplements, glucomannan itself is known to come with a number of potential benefits.
Potential Benefits of Glucomannan:
1. Can reduce blood sugar and insulin levels.
Glucomannan is a viscous fiber that moves through the digestive system very slowly and, in turn, slows nutrient absorption. This prompts glucose and insulin levels to rise slower.
2. Acts as a probiotic.
Glucomannan is beneficial for the bacteria living in your colon. Bacteria ferment the glucomannan, transforming it into short-chain fatty acids. This in turn can prevent or reduce inflammation and boost gut health, among other health benefits.
3. May lower cholesterol levels.
While there have been no conclusive studies in this direction, researchers note that glucomannan does increase cholesterol excretion, which in turn leaves less cholesterol to be reabsorbed in the bloodstream.
4. Helps promote weight loss.
Not necessarily in its supplemental form (though there is anecdotal evidence that some have benefitted from them), but in the form of noodles and rice. This is due to the same reason it helps with lowering glucose and insulin levels: slow absorption.
Glucomannan-based products are filling and keep you full for a long time – all at the expense of next to no calories. In this case, it works as a tool of ‘calories in, calories out’ – since a serving of shirataki noodles is less than 5 calories, but lasts a dieter long time, it helps cut down on daily calorie consumption.
That said, some studies have shown that overindulging in glucomannan-based products may come with some side-effects.
Potential Side-Effects of Glucomannan:
1. Can cause gastrointestinal issues.
A large amount of glucomannan may cause gas, bloating, and diarrhea. This is usually due to serving sizes: stop consuming them for a while and reduce the serving size when you start consuming them again.
2. May interfere with drug absorption.
Due to its slow-absorbing nature, glucomannan may hinder the body from absorbing medication taken with it. Make sure to take any medication or supplements you use at least one hour before or after consuming glucomannan-based products.
3. May encourage nutrient deficiency.
Products containing glucomannan are mostly water. While glucomannan does come with certain benefits, these products are not rich in nutrients. Glucomannan-based products like shirataki noodles take up a lot of space in your stomach, which may leave you short on vitamins and minerals, not to mention fat. So make sure to use it alongside nutrient-rich food.
4. Acts as a choking hazard.
While this is thankfully not something to worry about when it comes to products like shirataki noodles (since they contain water on their own), if you decide to take glucomannan-based supplements in pill, capsule, or powder form, make sure to take them with a lot of water. Otherwise, there’s a risk of them blocking the throat, esophagus, or intestines.
It should be noted that all of the abovementioned side-effects are either minor or easily mitigated by following certain recommendations. Simply do not overindulge and benefits will outweigh the risks.