January 20, 2010

Shirataki Noodles, Glucomannan and Konjac Fiber Examined

The Wall Street Journal recently published an article entitled "Noodling Your Way to Weight Loss" that looked at the potential health benefits of konjac fiber, a primary ingredient in Asian Shirataki noodles. Shirataki noodles are very low calorie, almost carbohydrate-free gummy noodles composed mostly of water and glcomannan (another name for konjac fiber). These noodles have gotten a lot of press from weight loss and low carb bloggers as they are a starch product high in fiber but relatively low in calories - here's a smattering:
These products might be low carb or low calorie, but do Shirataki noodles, konjac fiber and glucomannan supplements really promote health? The WSJ article cites a University of Connecticut meta-analysis that looked at 14 studies that shows the fiber does help lower LDL, promotes glucose regulation and mildly affect weight loss. A number of other studies analyzing the effects of konjac glucomannan (KGM) supplements have shown somewhat promising results as well:
  • A Diabetes Care study published in 2000 found that the soluble fiber found in Konjac-mannan based foods does improve glycemic control and lipid profiles
  • A Journal of Nutrition article examined the effect of Konjac-mannan in baboons fed Western diets and determined that use of the supplement decreased triglycerides and increased proportion of HDL to total cholesterol when compared to non Konjac-mannan fortified diets
  • The International Journal of Obesity reported that glucomannan may be helpful in promoting significant weight loss and reducing serum cholesterol and LDL over an eight-week trial period
But these health benefits are the type that are garnered from increasing dietary fiber and soluble fiber intake across the board, not just from one specific supplement or noodle product. The WSJ article quotes Abhimanyu Garg, chief of the division of nutrition and metabolic diseases at the University of Texas Southwestern Medical Center in Dallas. He points out that there's nothing really magical about one type of soluble fiber over another, "If you are eating papayas or apricots or dates, you are increasing soluble fiber while also getting vitamins and minerals". So while Shirataki noodles may be a good source of low-carbohydrate soluble dietary fiber, they most likely don't provide any "miracles" above and beyond that of any other naturally soluble-fiber containing food product.