Alfalfa

Scientific Name(s): Medicago sativa L. Common cultivars include Weevelchek, Saranac, Team, Arc, Classic, and Buffalo. Family: Leguminosae (beans)

Common Name(s): Alfalfa

Uses

There is no evidence supporting the use of various parts of the alfalfa plant for diuretic, anti-inflammatory, antidiabetic, or antiulcer purposes. Results from 1 small human study showed that the plant might reduce cholesterol levels.

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Dosing

Alfalfa seeds are used commonly as a supplement to lower cholesterol at doses of 0.75 to 3 g/day; however, clinical trials have not been performed to validate this dosage.

Contraindications

The FDA issued an advisory indicating that children, the elderly, and people with compromised immune systems should avoid eating alfalfa sprouts because of frequent bacterial contamination.

Pregnancy/Lactation

Documented adverse effects. May cause uterine stimulation. Avoid use.

Interactions

The vitamin K found in alfalfa can antagonize the anticoagulant effect of warfarin, resulting in decreased anticoagulant activity and lowered prothrombin time. Based on the potential immunostimulating effect of alfalfa, it has been theorized that alfalfa may interfere with the immunosuppressive action of corticosteroids (eg, prednisone) or cyclosporine.

Adverse Reactions

Alfalfa ingestion, especially of the seeds, has been associated with various deleterious effects, and alfalfa seeds and fresh sprouts can be contaminated with bacteria such as S. enterica and E. coli . The FDA issued an advisory indicating that children, the elderly, and people with compromised immune systems should avoid eating alfalfa sprouts. Ingestion of dried alfalfa preparations is generally without important side effects in healthy adults.

Toxicology

Alfalfa tablets have been associated with the reactivation of SLE in at least 2 patients. Changes in intestinal cellular morphology were noted in rats fed alfalfa.

Botany

This legume grows throughout the world under widely varying conditions. A perennial herb, it has trifoliate dentate leaves with an underground stem that is often woody. Alfalfa grows to approximately 1 m and its blue-violet flowers bloom from July to September.

History

Alfalfa has played an important role as a livestock forage. Its use probably originated in Southeast Asia. The Arabs fed alfalfa to their horses, claiming it made the animals swift and strong, and named the legume “Al-fal-fa” meaning “father of all foods.” The medicinal uses of alfalfa stem from anecdotal reports that the leaves cause diuresis and are useful in the treatment of kidney, bladder, and prostate disorders. Leaf preparations have been touted for their antiarthritic and antidiabetic activity, for treatment of dyspepsia, and as an antiasthmatic. Alfalfa extracts are used in baked goods, beverages, and prepared foods, and the plant serves as a commercial source of chlorophyll and carotene. 1

Chemistry

Dried alfalfa leaves are ground and sold as tablets or powder for use as nutritional supplements. Leaf tablets are rich in protein, calcium, trace minerals, carotene, vitamins E and K, and numerous water-soluble vitamins. 2 A steroidal saponin fraction composed of several factors (eg, soyasapogenols, hederagenin, medicagenic acid) 3 , 4 is believed to play a role in the hypocholesterolemic and hemolytic activity of the leaves and sprouts. 5 Alfalfa seeds contain the toxic amino acid L-canavanine, an analog of arginine. Sprouts of certain cultivars of alfalfa contain up to 13 g/kg canavanine (dry weight). Canavanine levels decrease as the plant matures. The alkaloids stachydrine and l-homo-stachydrine found in the seed possess emmenagogue and lactogenic activity. 6 Seeds contain up to 11% of a drying oil used in the preparation of paints and varnishes. The chemistry of alfalfa has been well characterized. 1

Uses and Pharmacology

There is no evidence that alfalfa leaves or sprouts possess effective diuretic, anti-inflammatory, antidiabetic, or antiulcer activity in humans. Alfalfa saponins are hemolytic in vitro. 7

Cholesterol reduction

Alfalfa plant saponins and fiber 8 bind significant quantities of cholesterol in vitro; sprout saponins interact to a lesser degree. In vitro bile acid adsorption is greatest for the whole alfalfa plant, and this activity is not reduced by the removal of saponins from the plant material.

Animal data

Several studies indicate that the ingestion of alfalfa reduces cholesterol absorption and atherosclerotic plaque formation in animals. 9 , 10 , 11 , 12 In 1 study, the ability of alfalfa to reduce liver cholesterol accumulation in cholesterol-fed rats was enhanced by the removal of saponins. Therefore, alfalfa plant saponins appear to play an important role in neutral steroid excretion, but are not essential for increasing bile acid excretion. 13 In a study with prairie dogs, the lowest incidence of cholesterol gallstones was obtained with the diet of the higher fiber content (85% alfalfa). 12

Clinical data

In a study of 15 patients, alfalfa seeds added to the diet helped normalize serum cholesterol concentrations in patients with type II hyperlipoproteinemia. 14

Cholestaid , a product available in the US containing 900 mg of Esterin patented process alfalfa extract with 100 mg citric acid, is said to neutralize the cholesterol in the stomach before it reaches the liver, thus facilitating the excretion of cholesterol from the body with no side effects or toxicity. 15 , 16 There is no evidence that canavanine or its metabolites affect cholesterol levels.

Dosage

Alfalfa seeds are used commonly as a supplement to lower cholesterol at doses of 0.75 to 3 g/day; however, clinical trials have not been performed to validate this dosage.

Pregnancy/Lactation

Documented adverse effects. May cause uterine stimulation. Avoid use. 17 , 18

Interactions

The vitamin K found in alfalfa can antagonize the anticoagulant effect of warfarin, resulting in decreased anticoagulant activity and lowered prothrombin time. 19 Based on the potential immunostimulating effect of alfalfa, it has been theorized that alfalfa may interfere with the immunosuppressive action of corticosteroids (eg, prednisone) or cyclosporine. 20

Adverse Reactions

Alfalfa seeds and sprouts can be contaminated with such pathogens as Salmonella enterica and Escherichia coli . 21 , 22 , 23 , 24 Most healthy adults exposed to salmonella or E. coli will have symptoms such as diarrhea, nausea, abdominal cramping, and fever that are self-limiting. The E. coli infection can lead to hemolytic uremic syndrome with kidney failure or death in children or the elderly. In 1995, 4 outbreaks of Salmonella infection occurred in the US because of the consumption of contaminated alfalfa sprouts. In 1995 to 1996, 133 patients in Oregon and British Columbia developed salmonellosis from ingesting alfalfa sprouts contaminated with S. enterica (serotype Newport). 21 Also in 1995, 242 patients in the US and Finland developed salmonellosis from ingesting alfalfa sprouts contaminated with S. enterica (serotype Stanley). 22 In June and July 1997, simultaneous outbreaks of E. coli 0157:H7 infection in Michigan and Virginia were independently associated with eating alfalfa sprouts grown from the same seed lot. 23 The FDA issued an advisory indicating that children, the elderly, and people with compromised immune systems should avoid eating alfalfa sprouts. 24

Toxicology

Changes in intestinal cellular morphology were noted in rats fed alfalfa; these effects were more extensive in animals fed whole plant material compared with sprouts. The interaction of saponins with cholesterol in cell membranes may only be partly responsible for these changes. 13 The importance of the changes in animal intestinal morphology is not clear; it is known that these changes, when observed concomitantly with changes in steroid excretion, may be related to an increased susceptibility to colon cancer. 25

A disease similar to systemic lupus erythematosus (SLE) has been observed in monkeys fed alfalfa seeds. 26 The disease was characterized by hemolytic anemia, decreased serum complement levels, immunologic changes, and deposition of immunoglobulins in the kidney and skin. Alfalfa ingestion has resulted in pancytopenia and hypocomplementenemia in healthy subjects. 27 L-canavanine has been implicated as the possible causative agent. The toxicity of L-canavanine is mainly due to its structural similarity to arginine. Canavanine binds to arginine-dependent enzymes interfering with their action. Arginine reduces the toxic effects of canavanine in vitro. 28 Further, canavanine may be metabolized to canaline, an analog of ornithine. Canaline may inhibit pyridoxal phosphate and enzymes that require the B 6 cofactor. 14 L-canavanine has also been shown to alter intercellular calcium levels 29 and the ability of certain B or T cell populations to regulate antibody synthesis. 30 , 31 Alfalfa tablets have been associated with the reactivation of SLE in at least 2 patients. 32

A case of reversible asymptomatic pancytopenia with splenomegaly has been reported in a man who ingested up to 160 g of ground alfalfa seeds daily as part of a cholesterol-reducing diet. His plasma cholesterol decreased from 218 mg/dL to 130 to 160 mg/dL. 27 Pancytopenia was believed to be due to canavanine.

A popular self-treatment for asthma and hay fever suggests the ingestion of alfalfa tablets. There is no scientific evidence that this treatment is effective. 33 Fortunately, the occurrence of cross-sensitization between alfalfa (a legume) and grass pollens appears unlikely, assuming the tablets are not contaminated with materials from grasses. 34 One patient died of listeriosis following the ingestion of contaminated alfalfa tablets. 35

Bibliography

1. Duke J. Handbook of Medicinal Herbs . Boca Raton, FL: CRC Press; 1985.
2. Worthington-Roberts B, Breskin M. Fads or facts? A pharmacist's guide to controversial “nutrition products.” Am Pharm . 1983;NS23:30-42.
3. Massiot G, et al. Reinvestigation of the sapogenins and prosapogenins from alfalfa ( Medicago sativa ). J Ag Food Chem . 1988;36:902.
4. Oleszek W. Solid-phase extraction-fractionation of alfalfa saponins. J Sci Food Ag . 1988;44:43.
5. Malinow MR, McLaughlin P, Naito HK, Lewis LA, McNulty WP. Effect of alfalfa meal on shrinkage (regression) of atherosclerotic plaques during cholesterol feeding in monkeys. Atherosclerosis . 1978;30:27-43.
6. AHA Quarterly Newsletter . 1984;3:4.
7. Small E, et al. The evolution of hemolytic saponin content in wild and cultivated alfalfa ( Medicago sativa , Fabaceae). Econ Bot . 1990;44:226.
8. Story J, et al. Adsorption of bile acids by components of alfalfa and wheat bran in vitro. J Food Sci . 1982;47:1276.
9. Malinow MR, McLaughlin P, Papworth L, et al. Effect of alfalfa saponins on intestinal cholesterol absorption in rats. Am J Clin Nutr . 1977;30:2061-2067.
10. Malinow MR, Connor WE, McLaughlin P, et al. Cholesterol and bile acid balance in Macaca fascicularis. Effects of alfalfa saponins. J Clin Invest . 1981;67:156-162.
11. Wilcox EB, Galloway LS. Serum and liver cholesterol, total lipids and lipid phosphorus levels of rats under various dietary regimes. Am J Clin Nutr . 1961;9:236-243.
12. Cohen BI, Mosbach EH, Matoba N, Suh SO, McSherry CK. The effect of alfalfa-corn diets on cholesterol metabolism and gallstones in prairie dogs. Lipids . 1990;25:143-148.
13. Story JA, LePage SL, Petro MS, et al. Interactions of alfalfa plant and sprout saponins with cholesterol in vitro and in cholesterol-fed rats. Am J Clin Nutr . 1984;39:917-929.
14. 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;65:173-179.
15. Levy S. New product newswire. Drug Topics . 1999;19:22.
16. Dewey D. Cholestaid. NuPharma . January 1, 2001.
17. Brinker FJ. Herb Contraindications and Drug Interactions . 2nd ed. Sandy, OR: Eclectic Medical Publications; 1998.
18. Ernst E. Herbal medicinal products during pregnancy: are they safe? BJOG . 2002;109:227-235.
19. Brown CH. Overview of drug interactions. US Pharmacist [online]. http://uspharmacist.com/oldformat.asp?url=newlook/files/feat/mar00druginteractionshtml .
20. Miller LG. Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions. Arch Intern Med . 1998;158:2200.
21. Van Beneden CA, Keene WE, Strang RA, et al. Multinational outbreak of Salmonella enterica serotype Newport infections due to contaminated alfalfa sprouts. JAMA . 1999;282:158-162.
22. Mahon BE, Ponka A, Hall WN, et al. An international outbreak of Salmonella infections caused by alfalfa sprouts grown from contaminated seeds. J Infect Dis . 1997;175:876-882.
23. CDC. Outbreaks of Escherichia coli 0157:H7 infection associated with eating alfalfa sprouts—Michigan and Virginia, June-July 1997. JAMA . 1997;278:809-810, and MMWR . 1997;46:741-744.
24. Christy C. Foodborne diseases: fruits and vegetables. Pediatr Infect Dis J . 1999;18:911-912.
25. Sprinz H. Factors influencing intestinal cell renewal. Cancer . 1971;28:71-74.
26. Malinow M, et al. Systemic lupus erythematosus-like syndrome in monkeys fed alfalfa sprouts: role of a nonprotein amino acid. Science . 1982;216:415-417.
27. Malinow MR, Bardana EJ Jr, Goodnight SH Jr. Pancytopenia during ingestion of alfalfa seeds. Lancet . 1981;1(8220 Pt 1):615.
28. Natelson S. Canavanine to arginine ratio in alfalfa ( Medicago sativa ), clover ( Trifolium ), and the jack bean ( Canavalia ensiformis ). J Ag Food Chem . 1985;33:413.
29. Morimoto I. A study on immunological effects of L-canavanine. Kobe J Med Sci . 1989;35:287-298.
30. Prete P. The mechanism of action of L-canavanine in inducing autoimmune phenomena. Arthritis Rheum . 1985;28:1198-1200.
31. Morimoto I, Shiozawa S, Tanaka Y, Fujita T. L-canavanine acts on suppressor-inducer T cells to regulate antibody synthesis: lymphocytes of systemic lupus erythematosus patients are specifically unresponsive to L-canavanine. Clin Immunol Immunopathol . 1990;55:97-108.
32. Roberts JL, Hayashi JA. Exacerbation of SLE associated with alfalfa ingestion. N Engl J Med . 1983;308:1361.
33. Polk I. Alfalfa pill treatment of allergy may be hazardous. JAMA . 1982;247:1493.
34. Brandenburg D. Alfalfa of the family Leguminosae. JAMA . 1983;249:3303-3304.
35. Farber JM, Carter AO, Varughese PV, Ashton FE, Ewan EP. Listeriosis traced to the consumption of alfalfa tablets and soft cheese. N Engl J Med . 1990;322:338.

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