Glucomannan is a water-soluble dietary fiber made from the roots of the Asian Konjac plant. Glucomannan makes up the majority of the solid substance in shirataki noodles. Eating lots of dietary fiber, which is found only in plant foods (such as whole grains, fruits, vegetables, beans, seeds and nuts) has been proven to have many health benefits.
For example, water-soluble dietary fiber helps decrease blood cholesterol levels. Blood cholesterol levels below 200 mg/dL have been associated with a reduced risk of coronary heart disease. The body gets rid of cholesterol through excretion of bile acids, and since water-soluble fiber binds bile acids, there is evidence that suggests a high-fiber diet results in increased excretion of cholesterol.
Fiber may also be beneficial in treating or preventing constipation, hemorrhoids, and diverticulosis (where pouches of the intestinal wall become inflamed and painful). Some research has also linked a high-fiber diet to a reduced risk of colon cancer. The FDA publishes claims outlining this evidence:
Diets low in fat and rich in fruits and vegetables, which are low-fat foods and may contain fiber or vitamin A (as beta-carotene) and vitamin C, may reduce the risk of some cancers.