Alfalfa is a legume that has a long history of dietary and medicinal uses. A small number of animal and preliminary human studies report that alfalfa supplements may lower blood levels of cholesterol and glucose. However, most research has not been well-designed. Therefore, there is not enough reliable evidence available to form clear conclusions in these areas.
Alfalfa supplements taken by mouth appear to be generally well tolerated. However, ingestion of alfalfa tablets has been associated with reports of a lupus-like syndrome or lupus flares. These reactions may be due to the amino acid L-canavanine, which appears to be present in alfalfa seeds and sprouts, but not in the leaves. There are also rare cases of pancytopenia (low blood counts), dermatitis (skin inflammation), and gastrointestinal upset.
These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
Several studies in animals report reductions in cholesterol plaques of the arteries after use of alfalfa. Well-designed research in humans is necessary before a firm conclusion can be drawn.
A small number of animal studies report reductions in blood sugar levels following ingestion of alfalfa. Human data are limited, and it remains unclear if alfalfa can aid in the control of sugars in patients with diabetes or hyperglycemia.
Reductions in blood levels of total cholesterol and low-density lipoprotein ("bad cholesterol") have been reported in animal studies and in a small number of human cases. High-density lipoprotein ("good cholesterol") has not been altered in these cases. Although this evidence is promising, better research is needed before a firm conclusion can be reached.
* Key to grades
A: Strong scientific evidence for this use B: Good scientific evidence for this use C: Unclear scientific evidence for this use D: Fair scientific evidence for this use (it may not work) F: Strong scientific evidence against this use (it likley does not work)
Tradition / Theory
The below uses are based on tradition, scientific theories, or limited research. They often have not been thoroughly tested in humans, and safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider. There may be other proposed uses that are not listed below.
The U.S. Food and Drug Administration does not strictly regulate herbs and supplements. There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
Alfalfa should be avoided in people with allergies to members of the Fabaceae or Leguminosae plant families. Caution is warranted in individuals with grass allergies.
Side Effects and Warnings
Alfalfa appears to be well tolerated by most individuals, although rare serious adverse effects have been reported.
Mild gastrointestinal symptoms may occur, such as stomach discomfort, diarrhea, gas, or larger/more frequent stools. Dermatitis (skin inflammation/redness) has been reported and may be due to alfalfa allergy.
Blood sugar levels may be reduced. Caution is advised in patients with diabetes or hypoglycemia, and in those taking drugs, herbs, or supplements that affect blood sugar. Serum glucose levels may need to be monitored by a healthcare provider, and medication adjustments may be necessary.
Lupus-like effects have been associated with alfalfa use, including antinuclear antibodies in the blood, muscle pains, fatigue, abnormal immune system function, and kidney abnormalities. Therefore, people with a history of lupus (systemic lupus erythematosus) or a family history of lupus should avoid alfalfa supplements.
Other rarely reported adverse effects include abnormal blood cell counts (pancytopenia) and lowered potassium levels (hypokalemia). In theory, thyroid hormone levels may be increased, gout flares may be stimulated, and estrogen-like effects may occur.
Contamination of alfalfa products with potentially dangerous bacteria (including Escherichia coli0157:H7, Salmonella, and Listeria monocytogenes) has been reported. In one case report, vomiting occurring after the consumption of seaweed and organic alfalfa was attributed to contamination of the capsules with high amounts of entospore forming and streptomyces-like bacteria. Copper, arsenic, and antimony have been found in alfalfa plants.
Many tinctures/liquid extracts contain high levels of alcohol and should be avoided when driving or operating heavy machinery.
Pregnancy and Breastfeeding
Alfalfa supplements are not recommended during pregnancy and breastfeeding due to insufficient evidence and a theoretical risk of birth defects or spontaneous abortion. Amounts found in food are generally believed to be safe. Traditionally, alfalfa is believed to stimulate breast milk production, although this has not been well studied.
Tinctures/liquid extracts may contain high levels of alcohol and should be avoided during pregnancy.
Blood sugar levels may be reduced. Caution is advised when using medications that may also lower blood sugar. Patients taking drugs for diabetes by mouth or insulin should be monitored closely by a qualified healthcare provider. Medication adjustments may be necessary.
Alfalfa contains vitamin K, and therefore may reduce the "blood thinning" effects of the drug warfarin (Coumadin®). Alfalfa may add to the effects of cholesterol-lowering medications such as atorvastatin (Lipitor®) or simvastatin (Zocor®).
Alfalfa may increase the risk of severe sunburns when used with drugs that increase sun sensitivity, such as chlorpromazine (Thorazine®). Due to estrogen-like chemicals in alfalfa, the side effects of drugs that contain estrogens may be increased (such as birth control pills or hormone replacement therapy). In theory, alfalfa may increase thyroid hormone levels and may alter the effects of thyroid drugs such as thyroxine (Synthroid®, Levoxyl®).
Alfalfa may alter potassium and calcium levels like other drugs.
Many tinctures/liquid extracts contain high levels of alcohol and may cause nausea or vomiting when taken with metronidazole (Flagyl®) or disulfiram (Antabuse®).
Alfalfa may also interact with drugs that alter the immune system.
Interactions with Herbs and Dietary Supplements
Blood sugar levels may be reduced. Caution is advised when using herbs or supplements that may also lower blood sugar such as aloe or bitter melon. Blood glucose levels may require monitoring, and doses may need adjustment.
Alfalfa may add to the effects of cholesterol-lowering agents such as fish oil, garlic, guggul, red yeast, and niacin.
Alfalfa has been reported to contain vitamin K, and therefore may reduce the effects of herbs and supplements that have blood-thinning effects that rely on depletion of vitamin K.
Because alfalfa contains estrogen-like chemicals, the effects of other agents believed to have estrogen-like properties, such as black cohosh, may be altered. Alfalfa may also alter thyroid levels in herbs such as bladderwrack.
Alfalfa may alter potassium and calcium levels. It may also interact with iron, vitamin E, and vitamin K.
Alfalfa may interact with therapies that alter the immune system or cause sun sensitivity.
Alfalfa may contain significant levels of zinc, copper, manganese, and selenium.
Anon. From the Centers for Disease Control and Prevention. Outbreaks of Escherichia coli O157:H7 infection associated with eating alfalfa sprouts--Michigan and Virginia, June-July 1997. JAMA 9-10-1997;278(10):809-810.
Bengtsson AA, Rylander L, Hagmar L, et al. Risk factors for developing systemic lupus erythematosus: a case-control study in southern Sweden. Rheumatology (Oxford) 2002;41(5):563-571.
Boue SM, Wiese TE, Nehls S, et al. Evaluation of the estrogenic effects of legume extracts containing phytoestrogens. J Agric Food Chem 4-9-2003;51(8):2193-2199.
Burden and causes of foodborne disease in Australia: Annual report of the OzFoodNet network, 2005. Commun Dis Intell 2006;30(3):278-300.
Farnsworth NR. Alfalfa pills and autoimmune diseases. Am J Clin Nutr 1995;62(5):1026-1028.
Hwang J, Hodis HN, Sevanian A. Soy and alfalfa phytoestrogen extracts become potent low-density lipoprotein antioxidants in the presence of acerola cherry extract. J Agric Food Chem 2001;49(1):308-314.
Lanza A, Tava A, Catalano M, et al. Effects of the Medicago scutellata trypsin inhibitor (MsTI) on cisplatin-induced cytotoxicity in human breast and cervical cancer cells. Anticancer Res 2004;24(1):227-233.
Malinow MR, McLaughlin P, Naito HK, et al. Regression of atherosclerosis during cholesterol feeding in Macaca fascicularis. Am J Cardiol 1978;41:396.
Malinow MR, McLaughlin P, Naito HK, et al. Effect of alfalfa meal on shrinkage (regression) of atherosclerotic plaques during cholesterol feeding in monkeys. Atherosclerosis 1978;30(1):27-43.
Malinow MR, McLaughlin P, Stafford C. Alfalfa seeds: effects on cholesterol metabolism. Experientia 5-15-1980;36(5):562-564.
Malinow MR, Bardana EJ Jr, Goodnight SH Jr. Pancytopenia during ingestion of alfalfa seeds. Lancet 3-14-1981;1(8220 Pt 1):615.
Molgaard J, von Schenck H, Olsson AG. Alfalfa seeds lower low density lipoprotein cholesterol and apolipoprotein B concentrations in patients with type II hyperlipoproteinemia. Atherosclerosis 1987;65(1-2):173-179.
Srinivasan SR, Patton D, Radhakrishnamurthy B, et al. Lipid changes in atherosclerotic aortas of Macaca fascicularis after various regression regimens. Atherosclerosis 1980;37(4):591-601.
Swanston-Flatt SK, Day C, Bailey CJ, et al. Traditional plant treatments for diabetes. Studies in normal and streptozotocin diabetic mice. Diabetologia 1990;33(8):462-464.
Van Beneden CA, Keene WE, Strang RA, et al. Multinational outbreak of Salmonella enterica serotype Newport infections due to contaminated alfalfa sprouts. JAMA 1-13-1999;281(2):158-162.
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.