Alfalfa

What it is

Alfalfa is a legume plant whose leaves, seeds and sprouts are eaten or sold as powders and tablets. It contains fibre and saponins, and its seeds and sprouts contain the amino acid L-canavanine.

What the research says

Alfalfa is mainly promoted for cholesterol. A few small human trials, including a 2024 randomised trial of alfalfa powder plus health education, report lower total and LDL cholesterol, but HDL did not differ and larger controlled trials are lacking. Harms include digestive upset, lupus-like illness linked to L-canavanine (seen in monkeys and a few human cases, still debated), and repeated food-poisoning outbreaks from raw sprouts.

Evidence grade: Limited evidence.

What goes wrong

Monkeys fed alfalfa sprouts developed a lupus-like syndrome, and a human volunteer eating alfalfa seed developed lupus-like autoimmunity; the human link from tablets remains controversial. (Source 1)

• Case report, Very low certainty.
• Size: A few human cases plus monkey and mouse studies.
• Who: Human volunteer and case reports; monkeys; lupus-prone mice.
• How long: Not stated.
• Result: Lupus-like rash, haemolytic anaemia, ANA and anti-dsDNA antibodies in monkeys.
• Funding: Not stated.

Monkeys fed with alfalfa sprouts developed a lupus-like syndrome characterized by macular erythematous rash, AIHA, ANA, anti-dsDNA antibodies

Digestive side effects including diarrhoea, bloating and abdominal discomfort have been reported with alfalfa supplements; rates were not given. (Source 2)

• Official position, Very low certainty.
• Size: Not stated.
• Who: Patients taking alfalfa supplements.
• How long: Not stated.
• Result: Rates not reported.
• Funding: Not stated.

Increased fecal volume and defecation frequency, loose stools and diarrhea as well as abdominal discomfort and intestinal gas have all been reported in patients, following supplementation with alfalfa.

Outbreak surveillance reported to CDC's National Outbreak Reporting System and summarised by Colorado State University counts raw sprouts, including alfalfa, as a recurring source of Salmonella and E. coli outbreaks in the US; these are counts of reported outbreaks, not a rate or a controlled comparison. (Source 3)

• Survey study, Moderate certainty.
• Size: 53 reported outbreaks, 1,498 illnesses.
• Who: US outbreak surveillance reports (CDC NORS), all sprout types.
• How long: 2000-2020.
• Result: 1,498 illnesses, 179 hospitalisations, 5 deaths.
• Funding: Not applicable.

Between 2000 and 2020, at least 53 sprout-associated outbreaks were reported to CDC's National Outbreak Reporting System (NORS), causing 1,498 illnesses, 179 hospitalizations, and 5 deaths.

Alfalfa may raise serum urate and urea. (Source 2)

• Official position, Very low certainty.
• Size: Not stated.
• Who: Not stated.
• How long: Not stated.
• Result: Not quantified.
• Funding: Not stated.

Alfalfa may increase serum urate and urea levels.

What the evidence supports

In a 160-person randomised trial, alfalfa powder plus health education lowered total cholesterol, LDL cholesterol and Apo A1 more than health education alone. (Source 4)

• Randomized trial, Low certainty.
• Size: 160 patients (80 per group)
• Who: Adults with dyslipidaemia at multiple sites in China.
• How long: 3 months.
• Result: Significant reductions in TC, LDL-C and Apo A1 vs education alone (exact values not in fetched abstract)
• Funding: Government grant (National Natural Science Foundation of China)

The intervention resulted in significant improvements in key lipid parameters in the Alfalfa group, including reductions in TC, LDL-C, and Apo A1 levels.

What the evidence does not support

In the same trial, HDL cholesterol change was not significantly different between groups. (Source 4)

• Randomized trial, Low certainty.
• Size: 160 patients.
• Who: Adults with dyslipidaemia in China.
• How long: 3 months.
• Result: HDL-C change not significantly different between groups.
• Funding: Government grant.

Although changes in HDL-C levels were not significantly different between the groups, the Alfalfa group exhibited a larger increase.

For diabetes, blood-sugar effects are seen only in animals and no human studies have tested it. (Source 2)

• Official position, Very low certainty.
• Size: No human trials.
• Who: Not applicable.
• How long: Not applicable.
• Result: None.
• Funding: Not stated.

Although alfalfa appears to lower blood glucose levels in animals, no studies have tested whether it has any significant effect in patients with diabetes.

Where the evidence is mixed

The authors themselves note human trial data are limited; MSKCC describes only two small trials and says larger controlled trials are needed. (Source 2)

• Official position, Very low certainty.
• Size: Two small trials.
• Who: People with high cholesterol.
• How long: Not stated.
• Result: Not stated.
• Funding: Not stated.

Two small trials have shown that alfalfa supplements lower cholesterol levels in people with high cholesterol, but larger, controlled trials are necessary to confirm these results.

Where the research disagrees

Whether alfalfa tablets can trigger or worsen lupus in humans

• Akaogi et al., Autoimmunity Reviews 2006, Narrative review of case reports, monkey and mouse studies: Induction or exacerbation of SLE by alfalfa tablets reported in a few cases remains controversial. (Source 1)

How much

• Reference intake: No reference intake exists; alfalfa is a plant food, not an essential nutrient. The sources we read set none. (Source 2)
• Upper limit: No UL or ADI has been set for alfalfa in the sources we read. (Source 2)
• Studied: A 2024 trial gave alfalfa powder together with health education for three months (dose not in fetched abstract). (Source 4)

A common belief, and what the research shows

The belief: Alfalfa sprouts are a harmless health food.

What the research shows: Sprouts grow in conditions that also suit pathogens: 'Sprouts require warm and humid conditions to grow, which is also ideal for bacterial pathogens such as Salmonella and E. coli.'

Questions and answers

What is it?

Alfalfa is a legume plant (Medicago sativa) eaten as sprouts or taken as leaf powder, seed or tablets. It contains fibre and saponins. (Source 2)

What does it do in the body?

Its saponins are thought to bind cholesterol in the gut. Small trials suggest lower total and LDL cholesterol, but the human evidence is limited. (Source 4)

Is it good or bad for you?

Mixed. Small trials suggest a cholesterol benefit, but seeds and sprouts contain L-canavanine, linked to lupus-like illness in animals and a few people, and raw sprouts carry food-poisoning risk. (Source 1)

How do you get more of it?

In trials people took alfalfa powder as a supplement; it is also eaten as sprouts. The trial that showed cholesterol changes combined it with health education. (Source 4)

If it is harmful, what reduces it?

Alfalfa is not something the body holds on to, so this mostly does not apply. For raw sprouts, US food safety advice is that higher-risk groups not eat them raw. (Source 3)

Why might someone be low in it or missing it?

Does not apply. Alfalfa is an optional plant food, not a nutrient the body needs, so there is no deficiency state. (Source 2)

We searched: Searched alfalfa human trials, reviews and MSKCC monograph; none describe a deficiency.

Which whole foods contain it or feed it?

Alfalfa itself is the food, most often eaten as sprouts; sprouting seeds are a known contamination route. (Source 3)

What happens if you do not have it?

Nothing is known to happen; alfalfa is not an essential nutrient. (Source 2)

We searched: Searched alfalfa reviews, trials and MSKCC monograph; no source describes effects of not eating alfalfa.

How can you test for it?

There is no test for alfalfa intake or status in the literature we searched. (Source 2)

We searched: Searched alfalfa trials and reviews; no biomarker test described.

References

1. Autoimmunity Reviews. Role of non-protein amino acid l-canavanine in autoimmunity. 2006. DOI 10.1016/j.autrev.2005.12.004. Read the source
2. Memorial Sloan Kettering Cancer Center. Alfalfa (About Herbs). 2023. Read the source
3. Colorado State University, Food Source Information. Sprouts - Food Source Information. n.d.. Read the source
4. Journal of Functional Foods. The effects of alfalfa powder combined with health education on patients with dyslipidemia: A randomized controlled trial. 2024. DOI 10.1016/j.jff.2024.106445. Read the source