Can a single herb treat something as benign as a common cold and as serious as cancer? Herbalists and a growing number of Western scientists believe the Chinese herb astragalus (Astragalus membranaceus) may do just that. The roots of this legume, native to China and Mongolia, have been used for thousands of years in Traditional Chinese Medicine (TCM) as a tonic to strengthen qi (pronounced “chi”), the so-called “life force” of the body.
What it Might Do: Astragalus is typically found in Chinese herbal formulas that treat weakness, shortness of breath and poor appetite. But extensive Chinese research—not necessarily to Western standards—documents diverse physiological actions, such as diuretic activity, improved circulation and liver protection. And TCM practitioners recommend astragalus for a wide range of disorders, from hepatitis and ulcers to diabetes and cardiovascular disease.
Though Western medicine may not be ready to embrace such disparate uses, it has begun to believe in the ability of astragalus to increase resistance to infection. In one Chinese study, astragalus combined with interferon (one of the body’s natural immune boosters) reduced the incidence of colds and sped recovery time. And at the University of Texas, test-tube studies offer the promise that astragalus may be able to offset immune damage caused both by cancer and its treatment. The effect astragalus would have in humans with cancer, however, remains to be tested.
How it Works: Polysaccharides in astragalus are believed to stimulate the production of immune cells, such as interferon, interleukin-2 and natural killer cells. Other constituents of astragalus, like saponins and bioflavonoids, may play a synergistic role in boosting immunity and exerting other beneficial effects of the herb.
If You Take: In China, astragalus root is commonly added to chicken broth to make a medicinal soup. Astragalus is more readily available in the U.S. in capsules or tinctures, alone or in combination with other herbs. Chinese medical texts list a typical daily dose of astragalus as four grams, though commercial products may contain less.
Caution: There are several species of astragalus, only one of which is used medicinally. Because other species may be toxic, such as locoweed found in the American West, be sure a label specifies Astragalus membranaceus root. Even in TCM, astragalus is often not recommended for acute illnesses, when there is fever and inflammation. And some researchers caution not to use it long-term if you have an autoimmune disease—a caveat for all immune boosters—because of fears it might promote the disease.
EN Weighs In: Astragalus is a highly valued herb in TCM, and its reputation in the West as an immune booster has been bolstered by laboratory data. Still, well-controlled human studies are lacking. The safety record for astragalus appears exemplary, however, so if you get recurrent infections, like colds or the flu, you might want to consider astragalus preventively for a time. And while you should never abandon traditional medical treatment for more serious conditions like cancer and AIDS, astragalus may be able to help rebuild and maintain immunity weakened by these diseases and their treatments.
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