Alfalfa extract
Also known as: Alfalfa, lucerne, Alfalfa extract, Medicago sativa L.
Overview
Alfalfa extract is derived from the leaves and stems of *Medicago sativa*, a leguminous plant. It is recognized for its rich nutritional profile, containing proteins, vitamins, minerals, and bioactive phytochemicals such as flavonoids and phenolic compounds. Traditionally, alfalfa has been used as a general tonic and for its purported anti-inflammatory, antioxidant, and hepatoprotective properties. The extract is commonly obtained through methanolic or aqueous extraction methods. While preclinical studies, particularly in animal models, suggest potential health benefits, human clinical trials and systematic reviews specifically on human health effects are limited. Research is moderately mature, with a significant focus on its applications in agriculture, such as animal feed.
Benefits
Preclinical evidence suggests several potential benefits for alfalfa extract. In a controlled animal study, alfalfa methanolic extract (AME) demonstrated significant antioxidant and hepatoprotective effects. Administered orally to rats, AME prevented nicotine-induced liver damage by reducing oxidative stress markers (malondialdehyde), improving antioxidant enzyme levels, lowering liver enzymes indicative of damage, and decreasing proinflammatory cytokines in a dose-dependent manner. The same study also showed reduced liver inflammation both histologically and biochemically. While alfalfa is rich in amino acids and micronutrients, which may contribute to general health, direct clinical evidence for these nutritional benefits in humans is limited. It's important to note that meta-analyses in broiler chickens indicate that alfalfa supplementation tends to decrease feed intake and body weight gain, while increasing feed conversion ratio, suggesting reduced growth performance in poultry, which is not relevant for human supplementation. The evidence for human benefits is currently insufficient, with most positive findings derived from animal models.
How it works
The primary mechanism of action for alfalfa extract's antioxidant activity is attributed to its phenolic compounds and flavonoids, which scavenge free radicals and reduce lipid peroxidation. Its anti-inflammatory effects likely involve the downregulation of proinflammatory cytokines in liver tissue. While the exact molecular targets are not fully elucidated, it is presumed to modulate oxidative stress pathways and inflammatory mediators within the body. Specific pharmacokinetic data regarding absorption and bioavailability in humans are currently lacking, though polysaccharides and flavonoids, common components of alfalfa, are known to have variable bioavailability depending on their structure and the matrix they are consumed in.
Side effects
Human safety data for alfalfa extract are limited, and no adverse effects were reported in the animal study at the tested doses. Alfalfa is generally considered safe as a food, but individuals sensitive to legumes may experience allergic reactions. Specific side effects have not been well-documented in the reviewed studies. Caution is advised for individuals on anticoagulant medications due to alfalfa's vitamin K content, which can interfere with blood clotting. Drug interactions and contraindications are not well-studied, necessitating a cautious approach, especially in special populations or those with pre-existing health conditions. Comprehensive safety warnings for human consumption are not yet established due to the lack of extensive human clinical trials.
Dosage
Recommended human dosages for alfalfa extract have not been established through high-quality randomized controlled trials. In animal models, specifically a rat study, an effective dose range of 100–500 mg/kg/day of methanolic extract was observed to show efficacy in preventing nicotine-induced liver damage. However, these animal doses cannot be directly extrapolated to humans without further research. The form of alfalfa extract used in studies often includes methanolic extracts, and polysaccharide derivatives are also being investigated for their functional properties. Due to the lack of human data, specific timing considerations, different dosages for various purposes, and absorption factors are not well-defined. Upper limits and safety thresholds for human consumption of alfalfa extract as a supplement are currently unknown.
FAQs
Is alfalfa extract effective for liver protection?
Preclinical evidence in rats suggests potential hepatoprotective effects via antioxidant and anti-inflammatory mechanisms, but human data are lacking.
Does alfalfa improve growth or performance in animals?
Meta-analyses indicate it may reduce growth performance in broiler chickens, likely due to high fiber content, which is not relevant for human health.
Is alfalfa extract safe for human consumption?
Generally safe in animal studies; however, human safety data are insufficient, and caution is advised for those on anticoagulants due to vitamin K content.
What is the best form for supplementation?
Methanolic extracts are commonly studied in research, and polysaccharide derivatives are also under investigation for their functional properties.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC8976666/ – This controlled animal study on 30 Wistar rats demonstrated that alfalfa methanolic extract (100–500 mg/kg/day) significantly prevented nicotine-induced liver damage. It achieved this by reducing oxidative stress markers, improving antioxidant enzyme levels, lowering liver enzymes, and decreasing proinflammatory cytokines in a dose-dependent manner, with histopathological confirmation of liver protection.
- https://advetresearch.com/index.php/AVR/article/view/2064 – This meta-analysis of 8 broiler performance studies found that alfalfa supplementation decreased feed intake and body weight, while increasing the feed conversion ratio. These statistically significant findings (p < 0.001) indicate reduced growth performance in poultry, likely due to its high fiber content.
- https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.1051725/full – This meta-analysis focused on alfalfa yield and quality response to fertilization, providing insights into alfalfa's nutrient-rich profile. While not directly relevant to human supplementation, it underscores the plant's nutritional value from an agronomic perspective.
