Safety and health claims
Konjac is not only used as a traditional food in China, Japan and South-east Asia; it is also registered for food usage in USA and, more recently, in the EU.
The Food Chemicals Codex lists the current uses of konjac flour in the United States as a gelling agent, thickener, film former, emulsifier. and stabiliser. USDA recently accepted the use of konjac as a binder in meat and poultry products. It is especially effective in emulsified meat products such as hot dogs and bologna, pepperoni, and summer sausage. In the EU, konjac flour has been granted E425. See the official EU gazette dated Nov.4,1999 : No.L295127, E-425, and Maximum dosage 10g/kg.
In fact, konjac flour has a long history of safe use. Its use as a food has been deeply rooted in the lives and customs of the people of China and Japan for centuries, Historically, konjac, the alkali treated konjac flour, was believed to cleanse one's digestive tract of irritating and poisonous substances and keep one's internal organs clean. The konjac tuber was introduced into Hawaii in 1858 and konjac was commonly eaten by the Japanese community on Hawaii.
The major component of konjac flour is Konjac Glucomannan. Feeding studies with rats and dogs indicate that there was no observed ill effects for glucomannan at 2.5% of the diet. There are several studies which deal with the effects of glucomannan on aspects of the biochemical dynamics of cholesterol, triglyceride, phospholipid, bile acid, glucose and insulin in experimental animals, while none of these studies can be called a safety study, they provide, some information on the safety of the glucomannan, in that they do not mention any adverse toxicological effects associated with the administration of glucomannan. These studies, in total, demonstrate that glucomannan has the ability to lower serum cholesterol levels and to delay glucose absorption.
Studies using glucomannan have been performed on humans, principally to study its influence on cholesterol and glucose absorption from the gastrointestinal tract. These studies indicate that glucomannan has the ability to lower serum cholesterol and may lower serum triglyceride and bile acid levels as well. Glucomannan may also have an influence on glucose tolerance and glucose absorption. These findings have also been seen in the animal studies, mentioned above.
Supplementation of appropriate amounts of Konjac in the diet can help prevent diabetes and aid gradual weight loss. Studies also indicate Konjac lowers Cholesterol levels. Konjac is ideal for weight reduction since Konjac forms a jelly like material and expands to about 30-50 times in volume in the digestive system and gives the feeling that the stomach is full. Recently, the food industry has started paying attention to Konjac flour as a replacement for conventional starch in formulations since Konjac is lower in calories and can help lower fat levels without sacrificing texture and taste.
Konjac has a very low calorific value (3Kcal/100g).