Saponins can be found in around 100 different plant families, including food sources such as beans and legumes, yams and yucca. These nutrient compounds have the ability to form stable foam and are found in products such as root beer and beer, shampoo and soap for this reason. Saponins from food sources may help decrease your cholesterol and lower your cancer risk, according to some researchers.
Saponins in beans, legumes and yucca may lower the cholesterol levels in your blood by blocking your body's absorption of cholesterol. Bile acid in your body binds with cholesterol to help your body absorb it. Saponins from the diet bind with bile acids and cholesterol so that they cannot enter your system. This reduces the amount of cholesterol your body absorbs and increases the amount it excretes.
Reduced Colon Cancer Risk
The same mechanism by which saponins may lower your cholesterol -- binding to bile acids -- may actually reduce your risk of colon cancer. According to the Linus Pauling Institute, some secondary bile acids promote colon cancer. Bacteria in your colon produce secondary bile acids from primary bile acids. By binding to primary bile acids, saponins reduce the amount of secondary bile acids your gut bacteria can produce, thereby reducing your risk of colon cancer. The Linus Pauling Institute states that feeding saponins to lab mice reduced the amount of precancer lesions in their colons. Researchers of a study published in 1995 in "Nutrition and Cancer" incubated human colon cancer tumor cells for one hour and 48 hours in various concentrations of saponins from soybeans and soapwort, an herb. They found the saponins inhibited tumor cell growth and reduced tumor cell activity in a dose-dependent manner -- the higher the concentration of saponins, the lower the tumor cell growth and activity.
According to researchers of a review published in 2010 in the journal "Fitoterapia," around 150 natural saponins have anti-cancer properties. They explain that the various chemical structures of saponins help prevent tumor formation. Ginsenosides, a saponin found in the ginseng plant, has been found to suppress tumor growth and the spreading of tumor cells to other organs, according to researchers of the 2010 review. They also found that dioscin and diosgenin from wild yam may actually cause tumor cell cycle arrest and death.
Possible Vaccine Use
The soapbark tree, also called Quillaja saponaria, which is native to Chile, has attracted a lot of attention from scientific researchers for the possible immune-boosting properties of the saponin in its bark. Currently, Quillaja saponin is being used in some vaccinations, but more research is needed to see if it could possibly be used in a vaccination for cancers and HIV. The mechanism behind the Quillaja saponin is that it helps stimulate your immune system response and production of T cells, which help your body fight infection. More research is needed because Quillaja saponin has drawbacks, including toxicity and instability in water solutions.