Psyllium is a Mediterranean plant in the plantain family, not to be confused with the banana-shaped fruit, according to UCLA botany professor Arthur C. Gibson. Its most commercially significant byproduct is its seed, which is surrounded by a mucilage-rich husk. When moistened, this water-soluble husk dissolves into a gel-like substance that delivers important nutritional and medicinal benefits. Because of this property, psyllium seed is commonly sold in health and supplement stores.
Psyllium seed is primarily sold and marketed as a dietary fiber supplement, according to "Mayo Clinic on Digestive Health" by John E. King. Its fiber is 47 percent soluble and 53 percent insoluble, which adds bulk to the stool and creates a healthy balance of bacteria in the colon and intestines when taken regularly as a dietary supplement.
Closely related to its role as a fiber booster, psyllium seed promotes better regularity, treating both constipation and diarrhea, according to the National Institutes of Health. It is the primary ingredient in Metamucil, Serutan and several other over-the-counter regularity aids. By restoring balance to the colon environment, it can solidify watery stools and soften hard stools, making both easier to pass.
According to "Herbal Therapy & Supplements: A Scientific & Traditional Approach" by Merrily A. Kuhn and David Winston, psyllium seed is clinically proven to lower cholesterol overall and to reduce the ratio of LDL cholesterol, or bad cholesterol, to HDL cholesterol, or healthy cholesterol. The National Institutes of Health notes that psyllium's cholesterol-lowering effects are modest and only appear after eight continuous weeks of use. While it can be part of an overall dietary approach to cholesterol control, the limitations of its effectiveness indicate that psyllium seed alone is not a sufficient solution for those with substantial cholesterol issues.
Gluten-Free Baking Ingredient
According to "The G-Free Diet: A Gluten-Free Survival Guide" by Elisabeth Hasselbeck and Peter Green, psyllium seed is commonly used as a baking ingredient by celiac disease sufferers and others who need or prefer a gluten-free diet. Gluten-free preparations of breads, muffins, pizza crusts and other baked goods tend to be drier and more fragile than their more traditional equivalents, but psyllium retains moisture and serves as a reasonable wheat gluten replacement. A study published in the "Journal of the American Dietetic Association" in October of 2009 states that bread prepared with psyllium was accepted by 93 percent of subjects with celiac disease and 97 percent of other subjects. It notes that while odor and texture are affected, the modified recipe is completely safe for celiac sufferers and lower in fat and calories than an equivalent recipe with gluten.