Although shirataki noodles have been around in Asia for quite some time, they're becoming increasingly popular outside of Asia with people who are trying to lose weight or who are cutting back on carbohydrates.
Shirataki noodles are made from the tubers of an Asian plant (Amorphophallus konjac) called a konjac plant. The tubers are dried and ground to make a flour which is then used to make noodles.
The noodles have a gelatinous consistency and have no real flavor.
Shirataki noodles contain almost no calories, carbohydrates, fat, sugar, protein, or gluten. Although shirataki noodles contain carbohydrates, very little of it is digested in the small intestine.
In addition to having almost no calories or usable carbohydrates, shirataki noodles contain a type of soluble fiber called glucomannan.
When glucomannan combines with water, it can swell to up to 17 times its original volume. When eaten, it swells in the digestive tract forming a gel-like mass, which is believed to promote a sense of fullness and keep food in the stomach longer.
It may work in other ways, such as reducing the amount of insulin produced after a meal.
Three small but well-designed studies have found that glucomannan supplements may promote weight loss, presumably by reducing hunger. Larger studies are needed.
Fiber is also known to help lower cholesterol, improve constipation by acting as a bulk laxative. Fiber also may help regulate blood sugar, possibly through a delay in stomach emptying.
A small study found that glucomannan may increase the amount of beneficial bacteria, such as lactobacillus acidophilus, in the intestines.
Studies have used glucomannan supplements (3 to 5 grams a day) rather than shirataki noodles, so most of the side effect and safety information is for the supplements. It's not known whether shirataki noodles are associated with the same side effects.
Side effects reported with glucomannan supplements include intestinal gas and bloating or mild diarrhea.People with intestinal obstruction, difficulty swallowing, and esophageal narrowing should not use glucomannan supplements.
A few precautions to note about glucomannan supplements:
- The tablet form should be avoided, because there have been cases of esophageal obstruction. The tablets lodged in their throats and swelled.
- People with diabetes should consult a doctor before using glucomannan. Glucomannan may lower blood sugar levels, so it can potentially cause hypoglycemia (blood sugar too low) may require adjustment of their diabetes medication because glucomannan may lower blood glucose levels.
- Pregnant and nursing women or young children should avoid glucomannan supplements.
- Glucomannan supplements must be taken with plenty of water or it may swell and cause an obstruction in digestive tract.
Shirataki noodles come packed in liquid. They have a fishy odor that many people find unpleasant, but it can be removed with thorough rinsing.
The only real downsides of shirataki noodles are that it's still hard to find and the consistency.
Many people feel they are rubbery. Boiling the noodles for two to three minutes helps soften them.
One variation on shirataki noodles that was created to more closely simulate the taste of regular noodles is tofu shirataki noodles. The noodles are opaque yellow-white like pasta noodles and aren't rubbery.
Shirataki noodles are often found in the fresh produce section of grocery stores near the tofu or in the refrigerated section near the dairy products.
Walsh DE, Yaghoubian V, Behforooz A. Effect of glucomannan on obese patients: a clinical study. Int J Obes. 8.4 (1984) 289-293.
Vido L, Facchin P, Antonello I, Gobber D, Rigon F. Childhood obesity treatment: double blinded trial on dietary fibres (glucomannan) versus placebo. Padiatr Padol. 28.5 (1993) 133-136.
Vuksan V, Jenkins DJ, Spadafora P, Sievenpiper JL, Owen R, Vidgen E, Brighenti F, Josse R, Leiter LA, Bruce-Thompson C. Konjac-mannan (glucomannan) improves glycemia and other associated risk factors for coronary heart disease in type 2 diabetes. A randomized controlled metabolic trial. Diabetes Care. 22.6 (1999): 913-919.