Konjac is a plant that manufacturers use to make high fiber dietary supplements, jellies, and flour. It plays a role in traditional Japanese and Chinese medicine.
The Latin name for the konjac plant is Amorphophallus. People also refer to it as konjaku, elephant yam, devil’s tongue, snake palm, and voodoo lily.
In this article, we explain the potential health benefits according to research. We also look at how to use konjac and some risks to consider before taking it as a supplement.
The konjac plant has a starchy root called a corm. This is high in a type of dietary fiber called glucomannan. Manufacturers use this part of the plant as a dietary supplement and in the production of high fiber flour and jellies.
Several different products use konjac corm, including:
- Konjac flour: Producers make this by grinding down dry konjac corms to make flour. People can then use this to make noodles.
- Konjac jelly: After further processing, konjac flour can form a jelly or gum. This can serve as an alternative to gelatin, which people can use as a food thickener.
- Konjac soluble fiber: Purifying konjac jelly further turns it into a soluble fiber that serves as a dietary supplement.
Konjac has several potential health benefits. Many of these benefits relate to its high content of glucomannan, the soluble dietary fiber that naturally occurs in the konjac plant.
The sections below discuss these potential health benefits in more detail.
1. Diabetes management
2. Weight management
Glucomannan made from konjac may be beneficial for people who are looking to lose weight.
A 2005 studyTrusted Source found that the soluble dietary fiber supplement helped people with overweight reduce their body weight. The participants took the supplement as part of a balanced, calorie-controlled diet.
However, one 2014 meta-analysisTrusted Source found that there was no benefit of using glucomannan versus a placebo for weight loss. Also, side effects of the fiber supplement included abdominal discomfort, diarrhea, and constipation.
Glucomannan may help a person feel full for longerTrusted Source by slowing the rate at which the digestive system empties.
Researchers compared the effects of the glucomannan supplement with those of a guar gum supplement. They found that the glucomannan supplement slightly increased weight loss, whereas the guar gum supplement did not.
However, other researchTrusted Source found that konjac did not promote weight loss or significantly alter body composition, change feelings of hunger or fullness, or improve lipids or blood glucose parameters, even though the participants seemed to tolerate the supplement well.
A 2019 study in ratsTrusted Source with diabetes found that administering konjac glucomannan significantly reduced total cholesterol levels, as well as low-density lipoprotein. This is known as “bad” cholesterol.
A study from 2017 investigated what dosage of glucomannan would be needed to improve cholesterol levels. Researchers found 3 grams per day to be beneficial.
Taking a glucomannan supplement may help regulate bowel movements and prevent constipation.
However, the researchers also found that taking glucomannan did not always improve stool consistency or the overall success rate of treatment.
A study from 2018Trusted Source also suggested that glucomannan supplementation can improve constipation symptoms during pregnancy. Glucomannan reportedly increased the frequency of stools and improved their consistency.
5. Healthy skin
The glucomannan content may also help people looking to improve the health of their skin.
6. Wound healing
As well as supporting skin health, glucomannan may also help the body heal wounds more quickly.
One 2015 study in mice found that glucomannan supplements might encourage wound healing by supporting the immune system. However, more research is necessary to conclude that glucomannan has the same effect in humans.
Konjac glucomannan dietary supplements are available in most health food stores. The precise dosage of konjac a person should take depends on their reason for taking it, as well as their age and overall health status.
The Food and Drug Administration (FDA) do not regulate konjac supplements, so it is vital to purchase them from a reputable retailer. Supplement manufacturers can voluntarily submit their products to an independent laboratory for testing of purity and potency, so check the label for this information.
People sometimes use konjac corm powder as an alternative to seafood in vegan food. Some manufacturers also make facial sponges from konjac for people looking to take advantage of the health benefits it has for the skin.
Other konjac products include:
- fruit jelly
When a person eats konjac in the form of fruit jelly, it may pose a choking risk, especially in children. This is because it absorbs a lot of water and does not dissolve readily. For this reason, it is important to chew konjac jelly thoroughly to ensure smooth swallowing.
In fact, the European Union and Australia have banned konjac jellies due to choking hazards.
Konjac supplements can also affect blood sugar levels, so people with diabetes should talk to a doctor before taking them.
Other people may experience diarrhea when they take konjac supplements. This is due to the way in which konjac impacts the gut and reduces constipation. Another way to reduce constipation is to drink plenty of water.
Konjac products may have health benefits. For example, they may lower blood sugar and cholesterol levels, improve skin and gut health, help heal wounds, and promote weight loss.
As with any unregulated dietary supplement, it is best to speak to a doctor before taking konjac. A person should also discuss konjac with a doctor before giving it to a child for constipation or other health concerns.
People should always consume konjac with water to prevent choking.