Glucomannan - Konjac Tuber | Goerlich Pharma

Glucomannan derived from the konjac tuber

Glucomannan aus der Konjac-Wurzelknolle | Goerlich Pharma
What is Glucomannan - Konjac Tuber | Goerlich Pharma

Description of the plant and substance

Glucomannan is a natural product obtained from the tubers of the konjac plant. The name “konjac” comes from its botanical name, Amorphophallus konjac, and the glucomannan-containing extract obtained from its tubers is known as konjac extract. The konjac plant grows in South Asia where, due to the tuber’s remarkable satiating effect, dishes made with its tubers have been cherished for around 1500 years. In Japan, it is known as konnyaku, in China as jǔruò and in Korea as gonyak. The konjac tuber naturally contains around 40% of glucomannan, which is built into the cell walls and provides the tuber with stability. Glucomannan itself is made up of long chains of carbohydrates which cannot be digested and is thus considered a fibre. The tubers are extracted in order to obtain the glucomannan. In the finished extract, the glucomannan content ultimately amounts to around 80%. [1,2]


The effects of glucomannan have been the subject of research for many years now. In doing so, these studies have demonstrated that glucomannan can be helpful for modern life in particular. Many of our problems arise due to poor diets. Our food often contains too much fat and low-fibre carbohydrates. A dietary supplement which contains glucomannan can have a positive influence on our nutritional balance

Many studies have already shown that glucomannan makes sense as part of a diet for those with diabetes. This is because it stabilises blood sugar levels, meaning that fluctuations are no longer as extreme. [3-7] In its capacity as a fibre, glucomannan also has positive effects on the body: regulating digestion and promoting the growth of healthy gut bacteria. [8-11]

Its effect on cholesterol levels is something which has been even more thoroughly researched. A high blood cholesterol level is a risk factor for cardiovascular problems which, like diabetes, are now counted among the diseases of civilisation whose frequency is very much on the rise thanks to our poor diets. By reducing cholesterol levels, glucomannan contributes towards reducing the risk of suffering from cardiovascular disea-ses. This effect has been investigated in depth by the European Food Safety Authority (EFSA), proven to be true, and considered to be meaningful information. This is why the following health claim has been approved for glucomannan at an intake of 4 g per day: glucomannan helps maintain normal blood cholesterol concen-trations. [12]

The most important effect of glucomannan is that it can contribute towards weight loss in people who are overweight. Excess weight damages the health of all organs and bones, as well as general well-being. The EFSA and EU Parliament considered this quality so helpful and important that they approved the only health claim which has ever been granted for an individual substance for the reduction of body weight to glucomannan at an intake of 3 g per day: glucomannan contributes to the reduction of body weight in the context of an energy-restricted diet. In doing so, the individual portion must contain at least 1 g of glucomannan. [13]

Mode of action

When combined with water, gluco-mannan produces a very satiating effect. It swells up in the stomach when combined with a glass of water. When the stomach is full, the body does not feel hunger, thus making it easy to eat less and to break down excess fat. As glucomannan is a non-digestible fibre, this satiating effect lasts for a long time. For this reason, glucomannan can be the natural and healthy key to a successful diet. What’s more, konjac extract can also become an inherent part of a healthy diet—as it is in its native continent of Asia. There is a saying which comes from traditional Chinese medicine: to treat an illness, you need a good doctor, but to keep your health you need a true master. Every individual is the master of their own health. [14]

Forms of dosage

Konjac extract can be used in a great deal of forms and varieties. The amount required for the weight loss stated in the health claim is achieved by taking 2 capsules—each containing 500 mg of glucomannan—3 times a day. Another practical way in which it can be presented is in the portioned end consumer-friendly stick (active contents: 1 g glucomannan), whose contents are stirred into a glass of water. This form allows for the konjac extract, which is neutral in taste, to be individually combined with many additional functional ingredients and flavourings. As a source of fibre, glucomannan can also be used as an addition to diet shakes and, at the same time, to contribute towards the coveted health claim made by the product.


Susanne Kühnl is the Projects and Development Manager at Goerlich Pharma GmbH. She completed her studies in food chemistry at the Technical University of Munich and will soon be completing her PhD at the University of Innsbruck on the subject of new anti-inflammatory and immunomodulating natural substances.


Literature / References

[1] Botanical Garden of the University of Basel
[2] amorphophallus/index.shtml
[3] Mainz University Botanic Garden
[5] Magnati et al., 1984
[6] Vuksan et al., 2000
[7] Vita et al., 1992
[8] Hou et al., 1990
[9] Vorster et al., 1985
[10] Marzio et al. 1989
[11] Cummings et al., 2004
[12] Passaretti et al., 1991
[13] Chen et al. 2006
[14] EFSA Journal 2009; 7(9):1258
[15] EFSA Journal 2010; 8(10):1798
[16] Xenius, Thema traditionelle Chinesische Medizin [the subject of traditional Chinese medicine], an AVE production on behalf of ZDF, in collaboration with ARTE


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