Guar gum--best known in the food industry as a filler and thickener for soups, gravies, salad dressing and other products--is earning a reputation as a cholesterol-lowering agent.
"It certainly has been shown to be effective in reducing blood cholesterol levels and in controlling blood sugar," says Karen Kovach, director of nutrition for the Cleveland Clinic in Ohio and a spokesperson for the American Dietetic Assn.
In recent studies at Stanford University's Center for Research in Disease Prevention, guar gum was three times as effective in lowering blood cholesterol levels as oat bran, a food widely hailed for its ability to reduce cholesterol. "You can see a reduction (in blood cholesterol levels) in about a week," says John W. Farquhar, director of the center.
Guar gum comes from the seed of the bean plant Cyamopsis tetragonoloba , which grows in Pakistan. The bean itself is not used for human consumption, but material extracted from it, namely the guar gum, is an important ingredient in many processed foods.
The advantage of guar gum is that it has no calories--one of the reasons for its growing use in recent years. Guar gum is an important ingredient in such low-calorie products as oil-free salad dressing, where it thickens without adding calories or fat.
Like oat bran, guar gum is a soluble fiber. Studies by David Kritchevsky at the Wistar Institute in Philadelphia suggest soluble fibers increase the amount of bile acid produced by the body. That in turn helps to gradually lower blood cholesterol levels. "If one were to do a head-to-head comparison of different soluble fibers, guar gum would be one of the most powerful," says Farquhar.
In a small study published last fall by Farquhar and his colleagues in the journal Arteriosclerosis and Thrombosis, guar gum was three times more effective at reducing blood cholesterol than oat-bran fiber. The 13 study participants averaged blood cholesterol levels of 244 milligrams, a level considered high by the National Heart, Lung and Blood Institute.
A water solution of guar gum taken three times daily at mealtimes for three weeks reduced levels of low density lipoprotein (LDL)--the so-called "bad" cholesterol--by 25 milligrams, more than twice the amount cut by oat bran. Guar gum also decreased triglyceride, another type of blood fat associated with a greater risk of heart disease, by 26 milligrams, about three times more than oat bran did.
The other advantage of guar gum is that it is more fiber-intensive than oat bran. It takes just 15 grams of guar gum to supply the same 11 grams of soluble fiber found in 77 grams of oat bran. The caution with guar gum is that it quickly forms a gel when mixed with liquid and thus must be blended with another substance, such as calcium carbonate, to keep it from solidifying.
For now, the main drawback is availability. Although guar gum can be found in many processed foods, it's not usually sold over the counter for consumption. "Pharmaceutical firms aren't interested because it can't be patented," Farquhar says.
Cutting saturated fat and dietary cholesterol helps reduce blood cholesterol by about 10%, studies show. Guar gum "is not as powerful as the omission of saturated fat and cholesterol," Farquhar says. "But here's another thing you can (do) to lower cholesterol."