May 1, 2001

4 Min Read
Soy Saponins

Soy Saponins

Numerous studies and publications suggest that soy isoflavones are among the dietary factors affording protection against menopausal symptoms, osteoporosis, heart problems, cancer and more. However, saponins found in soybeans are now thought by many researchers to have important synergistic functions withisoflavones.

Saponins are widely distributed in the plant kingdom. Soybeans, as a major source, have a saponin content of five to six percent by weight1. In one commercial product, it can be as high as 44 percent in a 40 percent soy isoflavone. Saponins are amphiphilic compounds composed of a lipid-soluble steroid moiety attached to a water soluble glycosidic chain.
Recent scientific research indicates that saponins have even more positive health benefits than first realized.

Lowering Cholesterol
The blood cholesterol-lowering properties of dietary saponins are of particular interest in human nutrition. Saponins bind cholesterol and bile acids in the gut. One of the most prominent research programs on this subject is that of Dr. Rene Malinow at the Oregon Regional Primate Center, whose research (published in theAmerican Journal of Clinical Nutrition in 1997) demonstrated unequivocally the cholesterol-lowering properties ofsaponins.
Saponins cannot penetrate the intestinal wall, but work within the small and large intestine, binding to cholesterol and making it unavailable for re-absorption2. The cholesterol is then passed into the colon and eventually excreted.

Reducing Cancer Risk
One of the most exciting prospects for saponins is how they appear to inhibit or kill cancer cells without killing normal cells. Cancer cells have more cholesterol-type compounds in their membranes than normal cells. Soy saponins can bind cholesterol and thus interfere with cell growth and division. This effect is attributed to saponins' antioxidant and anti-mutagenic properties3. While many drugs have serious side effects, saponins are believed to be quite safe. They arebroken down in the digestive tract into cholesterol-like compounds and sugars. For years, health experts have recognized the positive benefits of saponins as a nutritional supplement.

Soy saponins are shown to inhibit the growth of human colon carcinoma cells with low toxicity. Also, they are shown to decrease the ornithine decarboxylase activity that is directly related to cancer cell proliferation. In a study presented at the Third International Symposium on the Role of Soy in Preventing and Treating Chronic Disease (Washington, 1999), it was reported that soy saponins inhibit adduct formation. Adducts are precancerous changes that occur when a carcinogen binds to DNA.The results indicated that soy saponins may effectively reduce cellular DNA damage by carcinogens and can be regarded as a potential chemo-preventive agent.

Eliminating Toxins, Boosting Energy
Many of today's diets consist of "junk" food, including white flour, refined sugar, etc. When these foods are combined with insufficient digestive practices, the colon walls become coated with a pasty substance that prevents absorption of nutrients and minerals the body needs for good health. Saponins have the ability to loosen and dissolve hardened and impacted matter on the colon walls. Sickness and disease inevitably follow a significant buildup of toxins in the body.
Common symptoms and diseases attributed to toxic buildup in the body include arthritis, diverticulitis, constipation, loose stools and more. Everyone interested in good health is aware of the need to cleanse toxins from their digestive systems.
As we eliminate toxic buildup, we have more vitality and energy along with a renewed zest for living.

Increasing Immune System Strength
Apart from their important role in eliminating toxins in the body, soy saponins have other mechanisms for boosting our immune system. Soy saponins are already used as adjuvants for vaccines (increasing vaccine effectiveness). The Linus Pauling Institute newsletter noted, "Besides having adjuvant activity, saponins have a direct stimulatory effect on the immune system."

Acting On Viruses, Fungi
In plants, saponins act as the natural defense mechanism, protecting against attack by fungi, bacteria, yeast and other organisms. Numerous early examples of antifungal activity of saponins exist in medical literature. The mechanism of saponins againstfungi would appear to involve the formation of complexes with sterols in the plasma membrane, thus destroying the cellular semi-permeability and leading to death of the cell.
An in vitro study demonstrated saponins isolated from soybeans exhibited potent antiviral effects on the HIV virus. Saponin B1 completely inhibitedHIV-induced cytopathic changes and virus-specific antigen expression within six days after infection4.

Adding Taste
An added bonus for soy saponins is their taste. Many of them are quite sweet­up to 200 times the potency of table sugar (sucrose). Saponins in functional foods and drinks could have an added health promotional value.
With these health benefits, manufacturers may wish to seek out isoflavone ingredients with high saponin profiles. Solgen™ from Solbar Plant Extracts contains up to 44 percent saponins in 40 percent soy isoflavone ingredients.

1. Oakwndull D "Saponins in Food - A Review" Food Chem 6:19-40, 1981.
2. Clawson GA "Protease inhibitors and carcinogenesis: a review" Cancer Invest 14:597-608, 1996.
3. Elias R, DeMeo M, Vidal-Ollivier E, et al. "Antimutagenic activity of some saponins isolated from Calendula officinalis L., C arvensis L., and Hedra helix L." Mutagenesis 5:327-331, 1990.
4. Nakashima H, Okubo K, Honda Y, et al. "Inhibitory effect of glycosides like saponin from soybean on the infectivity of HIV in vitro" AIDS 3:655-658, 1989.

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