Botanicals/Herbs: Astragalus
By Diane Welland, MS, RD
Today’s Dietitian
Vol. 24 No. 7 P. 12

An Overview of the Herb’s Current Applications

Fall marks the beginning of cold and flu season and a time when many people turn to herbal remedies to stave off illness and stay healthy. Add to this the extra burden of a lingering pandemic that waxes and wanes throughout the year and it’s no wonder interest in herbal therapies that strengthen the immune system and reduce stress remains high. One such botanical receiving more attention to help prevent the common cold and flu and relieve stress is astragalus. A popular herb that has been used in traditional Chinese medicine for thousands of years, astragalus is believed to help strengthen the immune system, protect the body from disease, and manage stress.1,2

What Is Astragalus?
Also known as huang qi or milk vetch, astragalus is a perennial, tropical plant in the legume or bean family, native to northeastern China and parts of Korea and Mongolia.1,3 Of the more than 2,000 species, the most important and studied is astragalus membranaceus.4,5 In traditional Chinese medicine, astragalus claims to have several potential health benefits.

Enhances Immune Function
Most well-known as a potential immune-strengthening tonic, the majority of astragalus’ medicinal properties are attributed to flavonoids, saponins, and polysaccharides found in the root of the plant.2 Several Chinese studies done in vitro and in mice and other animals suggest these ingredients have immunomodulating effects that help enhance and protect immune-related organs, stimulate immune cells, boost lymphocyte activity, and reduce inflammation.2 Research is limited, but it shows promise. According to Mount Sinai Hospital in New York, US researchers consider astragalus a possible treatment for patients with cancer whose immune systems have been weakened by chemotherapy or radiation. The hospital system’s website says that in these studies, astragalus supplements seem to help people recover faster and live longer.1

Memorial Sloan Kettering Cancer Center’s review on astragalus says it may have anticancer effects against certain cancers. Preliminary data show astragalus also may help reduce chemo-induced side effects (eg, nausea and vomiting), especially those related to reduced appetite leading to decreased food intake.1-4

“Research on astragalus is actually quite robust and has been well accepted by many oncologists for postcancer treatment care,” says New York City–based Robin Foroutan, MS, RDN, an integrative and functional medicine specialist, certified holistic health coach, and owner of Nutrition By Robin. Nevertheless, more well-designed, larger research studies in the cancer population are needed to confirm these findings.

For Foroutan, astragalus is a good option for people who don’t feel their best. “Astragalus is my go-to herb for immune support, particularly for people who feel worn out, chronically fatigued, and just seem to get sick easily, “she says. “It can help strengthen the immune system so they don’t get sick.”

Beyond Immunity
Furthermore, astragalus’ benefits are believed to go well beyond immunity. In traditional Chinese medicine, astragalus is used to treat and/or prevent a multitude of conditions and disease states, and several studies have linked its medicinal use to help protect against diabetes by managing blood sugar levels, neurocognitive diseases, kidney disease, and heart disease, as well as helping improve liver function and support bone health.2,4,6,7

“Many of the mechanisms of action found in the astragalus root” are associated with “antibacterial, anti-inflammatory, antiviral, antioxidant, and anticancer effects,” says Monique Richard, MS, RDN, LDN, FAND, IFNCP, RYT, an integrative and functional medicine specialist, national media spokesperson for the Academy of Nutrition and Dietetics, and owner of Nutrition-In-Sight, LLC, in Johnson City, Tennessee. “In some research studies, astragalus appears to promote apoptosis, or programmed cell death, and as an ingredient in herbal formulations, it may be helpful in certain types of cancer as well as possibly increase lymphocyte activity.”

Possible Energy Booster
In addition to increasing immunity, astragalus often is used in combination with other herbs in traditional Chinese medicine to help boost energy, stamina, and vitality.3 In fact, limited clinical data suggest astragalus may be useful in managing cancer-related fatigue.1-3

“Astragalus is an adaptogen,” Foroutan says, “which means it adapts to your body’s needs. Adaptogens help to strengthen the proper function of the hypothalamus-pituitary-adrenal axis, which helps you become more resilient to stress and can improve energy levels.”

For this reason, many people who have weakened or low-level immunity turn to astragalus for help. In traditional Chinese medicine, astragalus often is combined with other adaptogenic herbs to help prevent colds and upper respiratory infections.1 One small study found that astragalus may help improve seasonal allergy symptoms.1,8

Antiaging Properties
Considering its long history of medicinal use and reported ability to reduce oxidative stress and inflammation, research also suggests astragalus may have antiaging effects, specifically on immune system cells.2,4 However, astragalus also may act in other ways. One recent study found that a single chemical (TA-65) isolated from the root of astragalus was shown to stimulate telomerase activity and potentially increase telomere length in mouse cells.4 Telomeres are DNA structures found at the ends of each chromosome and are required for cell division. As the cell ages, telomeres become shorter and shorter until the cell no longer can replicate and dies. Telomerase is an enzyme that can extend telomere length and, thus, the life of the cell.10,11

Forms and Dosages
In the United States, astragalus root generally is dried and most commonly used in dietary supplement form (ie, standardized capsules and tablets). However, individuals also can find it in tinctures (liquid form), powders, and dried root chips or slices online or in Chinese specialty stores. The dried root is known to have a pleasant taste and can be made as a tea or soup. A topical form for the skin also is available. In Asia, injectable forms are used in hospitals and other clinical settings.1,2,4

No official recommended standard dosage exists for astragalus, but according to the National Institutes of Health, doses up to 60 g daily for four months have been used without reported adverse effects. In supplement form, doses range anywhere from 500 mg to 2,000 mg per tablet or capsule. Astragalus generally is well-tolerated by adults and considered safe. Foroutan suggests low doses, anywhere from 200 mg to 800 mg per day, depending on the symptoms and “constitution” of the client. Potential side effects are mild and include rash, itching, nasal symptoms, headache, or upset stomach, but these are uncommon and often short-term.3,5,9 How much astragalus someone needs depends on the condition being treated, purpose of treatment, age, weight, and health status.1,4

Nevertheless, astragalus isn’t for everyone. Since it’s reported to stimulate immune function, individuals who have autoimmune diseases, such as rheumatoid arthritis or lupus, and those on immunosuppressant medications shouldn’t take it. Pregnant and breastfeeding women and young children also should avoid astragalus or check with their doctor before using it, since research is scant on these populations.1,3,5 Finally, be aware that astragalus may interact with other medications. For example, it may increase the effect of blood pressure–lowering drugs and diuretics and decrease the body’s ability to clear certain medications such as lithium.1,3

What RDs Need to Know
While research suggests that astragalus may help boost immunity, combat fatigue, and possess antiaging properties, typically, it isn’t recommended for use during acute infections, Foroutan says. “It’s a good recovery herb for after chemo and post cancer treatments and post viral recovery, but I wouldn’t recommend taking it when sick.”

Foroutan also says it’s a good herb to use while looking for underlying causes. “If someone comes in feeling chronically fatigued and tired, with a weakened or suboptimal immune system, I may suggest astragalus,” Foroutan says, “but it’s still important to do your due diligence and investigate any root cause issues such as those related to gut health, nutrient insufficiencies, abnormal blood work, or hidden infections like viruses.”

Esther Hansen, RDN, a certified first-line therapy provider, certified intuitive eating professional, and owner of Ft. Collins Nutrition in Northern Colorado, takes astragalus herself and advises dietitians to pay special attention to how a client responds to an herbal remedy. “Each person is different, so you need to tailor the dose to the person,” Hansen says. “Some people may be more sensitive.” In all cases, it’s important for dietitians to educate themselves about astragalus or any herb before making recommendations and always review databases for potential drug interactions. One of the best places to start is the American Botanical Council. Reputable dietary supplement companies also have information on specific herbs, and RDs should review the scientific literature. Often, there are evidence-based review studies that provide overviews of the herb and its safety and efficacy data.

— Diane Welland, MS, RD, is a writer, public relations professional, speaker, award-winning recipe developer, and author. She’s the director of nutrition communications at Kellen, an association management firm in Washington, D.C., where she specializes in tracking trends and translating nutrition science into layman’s terms.

References
1. Astragalus. Mount Sinai website. https://www.mountsinai.org/health-library/herb/astragalus#:~:text=In%20TCM%2C%20astragalus%20is%20used,appears%20t o%20lower%20blood%20sugar 

2. Ny V, Houška M, Pavela R, Tříska J, Potential benefits of incorporating Astragalus membranaceus into the diet of people undergoing disease treatment: an overview. J Funct Foods. 2021;77:104339.

3. Astragalus. Memorial Sloan Kettering Cancer Center website. https://www.mskcc.org/cancer-care/integrative-medicine/herbs/astragalus. Updated April 19, 2022.

4. Liu P, Zhao H, Luo Y. Anti-aging implications of astragalus membranaceus (Huangqi): a well-known Chinese tonic. Aging Dis. 2017;8(6):868-886.

5. Shane-McWhorter L. Astragalus. Merck Manual Consumer Version website. https://www.merckmanuals.com/home/special-subjects/dietary-supplements-and-vitamins/astragalus. Updated January 2022.

6. Li XY, Shen L, Ji HF. Astragalus alters gut-microbiota composition in type 2 diabetes mice: clues to its pharmacology. Diabetes Metab Syndr Obes. 2019;12:771-778.

7. Agyemang K, Han L, Liu E, et al. Recent advances in Astragalus membranaceus anti-diabetic research: pharmacological effects of its phytochemical constituents. Evid Based Complement Alternat Med. 2013;2013:654643.

8. Matkovic Z, Zivkovic V, Korica M, Plavec D, Pecanic S, Tudoric N. Efficacy and safety of Astragalus membranaceus in the treatment of patients with seasonal allergic rhinitis. Phytother Res. 2010;24(2):175-181.

9. Astragalus.National Institutes of Health, National Center for Complementary and Integrative Health website. https://www.nccih.nih.gov/health/astragalus. Updated August 2020.

10. Gomez DE, Armando RG, Farina HG, et al. Telomere structure and telomerase in health and disease (review). Int J Oncol. 2012;41(5):1561-1569.

11. Zvereva MI, Shcherbakova DM, Dontsova OA. Telomerase: structure, functions, and activity regulation. Biochemistry (Mosc). 2010;75(13):1563-1583.