Principal Proposed Uses
Alfalfa is one of the earliest cultivated plants, used for centuries for feeding livestock. This probably is true in part because it is easy to grow, thrives in many varied climates throughout the world, and provides an excellent protein-rich food source for cattle, horses, sheep, and other animals. The name alfalfa comes from the Arabian al-fac-facah, for "father of all foods."1 Its high protein content and abundant stores of vitamins make it a good nutritional source for humans, too. Historic (but undocumented) medicinal uses of alfalfa include treatment of stomach upset, arthritis, bladder and kidney problems, boils, and irregular menstruation.
Alfalfa sprouts appear on many salad bars and in the grocery's produce section. Bulk powdered herb or capsules and tablets containing alfalfa leaves or seeds are available in pharmacies and healthfood stores.
A typical dose of alfalfa for tea is 1 to 2 teaspoons per cup, steeped in boiling water for 10 to 20 minutes. Tablets and capsules of whole alfalfa or alfalfa extracts should be taken according to the manufacturer's recommendations. Certain products are said to be free of canavanine (see Safety Issues) and other potentially harmful constituents; these products may be preferable.2
Alfalfa is high in vitamin content—providing beta-carotene; various B-vitamins; and vitamins C, E, and K —and can be used as a nutritional supplement.3 However, keep in mind that high doses of alfalfa may present some health risks. (See Safety Issues below.)
Numerous animal studies4-15 and preliminary human trials 16,17,18 indicate that extracts from alfalfa seeds, leaves, and roots might be helpful for lowering cholesterol levels. However, there have not been any well-designed, double-blind, placebo-controlled trials demonstrating alfalfa useful for this (or any other) purpose. (For information on why double-blind studies are so important, see Why Does This Database Rely on Double-Blind Studies?)
Alfalfa has also been investigated in the laboratory (but not yet evaluated in people) as a source of plant estrogens, which might make it helpful for menopause.21,22,23 Alfalfa may also have some use in fighting fungi.24,25,26 Rats fed a disease-causing fungus were able to eliminate more of the fungus from their systems when fed a diet high in alfalfa. It has been suggested that one of the saponins from alfalfa causes damage to the cell membranes of fungi.
Finally, alfalfa has been proposed as a treatment for hay fever, but there is no scientific evidence that it is helpful for this purpose.
Alfalfa, in its various forms, may present some health risks. Powdered alfalfa herb, alfalfa sprouts, and alfalfa seeds all contain L-cavanine, a substance that may cause abnormal blood cell counts, spleen enlargement, or recurrence of lupus in patients with controlled disease. However, heating alfalfa may correct this problem.
Researchers investigating alfalfa seeds' ability to lower cholesterol levels discovered that it had another effect on the lab animals used for testing. In some of the monkeys, it caused a disease very similar to lupus.27 Further research on this effect revealed that monkeys that had abnormal blood cell counts when eating either alfalfa seeds or sprouts, and then recovered when alfalfa was no longer part of their diet, developed the symptoms again when given an isolated component of alfalfa called L-canavanine.28 Alfalfa seeds and sprouts have a higher concentration of L-canavanine than the leaves or roots.
In a clinical trial of alfalfa seeds for lowering cholesterol involving only 3 human volunteers, one man who participated developed pancytopenia (an abnormally low number of all of the various types of blood cells) and enlargement of the spleen.29 Additionally, there are two published case reports of patients, who had lupus which was controlled with drug therapy, suffering relapses after consuming alfalfa tablets. Again, L-canavanine is thought to be responsible for these effects.
When alfalfa seeds were autoclaved (heated to extremely high temperatures) and fed to monkeys for a year, no ill effects were seen, and the monkeys' cholesterol levels decreased.30 It may be that the L-canavanine can be destroyed by extreme heat, while the saponins that seem to be responsible for the beneficial effects of alfalfa remain intact. If so, a heat-treated product might prove safe; however, much research remains to be done before we can know this for certain.
At present, it seems prudent that people who have been diagnosed with lupus, or those who suspect a predisposition to it based on family history, should probably avoid alfalfa. This includes the tablets used for supplements and the sprouts on the salad bar (go for the lettuce or the spinach instead).
Because of the estrogenic effects of some of alfalfa's components, alfalfa is not recommended for pregnant or nursing women or young children. In addition, the high vitamin K content in alfalfa could, in theory, make the drug warfarin (Coumadin) less effective.
Finally, a number of cases of food poisoning have been documented from fresh sprouts infected with bacteria that was present on the seeds prior to germination.31,32,33 Unfortunately, sprouts can appear fresh and yet host enough bacteria to cause illness in people who eat them. Some healthcare workers recommend that those at higher risk for such infections—young children, those with chronic diseases, and the elderly—avoid eating sprouts altogether.
Interactions You Should Know About
If you are taking warfarin (Coumadin): the high vitamin K content of alfalfa might make it less effective.
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Last reviewed December 2015 by EBSCO CAM Review Board Last Updated: 12/15/2015