Alfalfa as a nutritional supplement
Alfalfa, scientifically known as Medicago sativa, is a nutritional supplement derived from one of the oldest cultivated plants, traditionally used to benefit livestock due to its high protein content. This plant is notable for its rich supply of vitamins, including vitamins K and C, as well as essential minerals such as magnesium and iron. People consume alfalfa for various health benefits, including nutritional support, allergy relief, cholesterol reduction, management of menopausal symptoms, and its potential antioxidant properties.
Alfalfa is available in multiple forms, including sprouts, powders, capsules, and tablets, making it accessible in health food stores and online. While some studies suggest it may help lower cholesterol levels and improve symptoms of diabetes, rigorous clinical trials validating these effects in humans are still lacking. Safety concerns do exist; for instance, alfalfa contains L-canavanine, which may cause adverse health effects in certain individuals, particularly those with lupus. Additionally, its high vitamin K content can interfere with blood thinners like warfarin. Given these factors, individuals, especially those pregnant, nursing, or with specific health conditions, should approach alfalfa with caution and consult healthcare professionals before use.
Alfalfa as a nutritional supplement
DEFINITION: Natural plant product consumed as a nutritional and dietary supplement for specific health benefits.
PRINCIPAL PROPOSED USE: Nutritional support
OTHER PROPOSED USES: Allergies, diabetes, lowering cholesterol, menopausal symptoms, antioxidant
Overview
Alfalfa is one of the earliest cultivated plants, and it has been used for centuries to feed livestock. The plant is easy to grow, thrives in many climates worldwide, and provides an excellent protein-rich food source for cattle, horses, sheep, and other animals. The name “alfalfa” comes from the Arabic al-fac-facah, meaning “father of all foods.” Its high protein content and abundant stores of vitamins make it a good nutritional source for humans. Alfalfa is high in vitamins K and C, and it contains folate, thiamine, riboflavin, magnesium, iron, and copper. Historical but undocumented medicinal uses of alfalfa include treatment of stomach upset, arthritis, bladder and kidney problems, boils, and irregular menstruation.
Requirements and Sources
Alfalfa sprouts are available in many salad bars and in the produce section of grocery stores. Bulk powdered herbs, capsules, and tablets containing alfalfa leaves or seeds are also available in pharmacies, health food stores, and online.
Therapeutic Dosages
A typical dose of alfalfa for tea is 1 to 2 teaspoons per cup, steeped in boiling water for ten to twenty 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 and other potentially harmful constituents; these products may be preferable.
Therapeutic Uses
Alfalfa is high in vitamin content. It provides beta-carotene, various B vitamins, and vitamins C, E, and K, and it can be used as a nutritional supplement. However, high doses of alfalfa may present some health risks.
Numerous animal studies and preliminary human trials indicate that extracts from alfalfa seeds, leaves, and roots might help lower total cholesterol, LDL (bad) cholesterol, and triglyceride levels while increasing HDL (good) cholesterol. However, well-designed, double-blind, placebo-controlled trials demonstrating alfalfa's usefulness for this (or any other) purpose are lacking in humans.
Studies using mice to investigate alfalfa’s traditional use for diabetes found that it improved some symptoms. Alfalfa has also been investigated in the laboratory (but not evaluated in people) as a source of plant estrogens, which might make it helpful for menopause. Alfalfa may also be used to fight fungi. Rats fed a disease-causing fungus could 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. Additionally, alfalfa has been proposed as a treatment for hay fever, but there is no scientific evidence that it is helpful for this purpose. In Tibetan sheep, alfalfa was found to improve body health and meat quality and support growth and development, indicating potential health benefits of the substance. Still, specific applications in humans must be further investigated.
Animal studies have noted that alfalfa's antioxidant properties may help treat conditions caused by inflammation and oxidative stress. Alfalfa appears to lower the production of free radicals in the body and improve the body’s ability to fight them. However, these results were only confirmed through test-tube studies of lab animals, and more human studies are necessary.
Safety Issues
Alfalfa, in its various forms, may present some health risks. Powdered alfalfa herb, alfalfa sprouts, and alfalfa seeds all contain L-canavanine. This substance may cause abnormal blood-cell counts, spleen enlargement, or recurrence of lupus in persons 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 monkeys, alfalfa seeds cause a disease very similar to lupus. 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. Alfalfa seeds and sprouts have a higher concentration of L-canavanine than the leaves or roots.
In a clinical trial of alfalfa seeds, designed to determine their efficacy in lowering cholesterol, one man developed pancytopenia (an abnormally low number of all the various types of blood cells) and enlargement of the spleen. However, only three individuals were in the study, so the findings were inconclusive. Additionally, there were published case reports of persons who had lupus that was controlled with drug therapy, suffering relapses after consuming alfalfa tablets. Again, L-canavanine was thought to be responsible for these effects.
When alfalfa seeds were autoclaved (heated to extremely high temperatures) and fed to monkeys for one year, no ill effects were seen, and the monkeys’ cholesterol levels decreased. 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.
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.
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, several cases of food poisoning have been documented from fresh sprouts infected with bacteria that were present on the seeds before germination. 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, such as young children, those with chronic diseases, and older adults, should avoid eating sprouts altogether.
Important Interactions
Persons taking warfarin should note that alfalfa's high vitamin K content might make warfarin less effective.
Bibliography
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Loui, C., et al. "Bacterial Communities Associated with Retail Alfalfa Sprouts." Journal of Food Protection, vol. 71, 2008, pp. 200-204.
Sadeghi, Leila et al. "Antioxidant Effects of Alfalfa Can Improve Iron Oxide Nanoparticle Damage: In Vivo and In Vitro Studies." Regulatory Toxicology and Pharmacology:RTP, vol. 81, 2016, pp. 39-46, doi:10.1016/j.yrtph.2016.07.010.
Su, Yingying. "Dietary Alfalfa Powder Supplementation Improves Growth And Development, Body Health, And Meat Quality Of Tibetan Sheep." Food Chemistry, vol. 396, 2022, p. 133709. doi.org/10.1016/j.foodchem.2022.133709.
Warwick, Kathy W., and Debra Rose Wilson. "Alfalfa: Benefits, Nutrition Facts & Side Effects." Healthline, 29 Sept. 2021, www.healthline.com/nutrition/alfalfa. Accessed 4 Sept. 2024.