Fava beans carry a natural medicine. They contain L-dopa, the same compound used as a medicine for Parkinson’s disease. When 13 healthy volunteers ate fava beans in one study, their blood dopa rose within an hour and plasma dopamine increased nearly 15-fold.
The same beans can be dangerous. In people with G6PD deficiency, an inherited enzyme condition, eating fava beans can set off favism, a sudden breakdown of red blood cells (hemolytic anemia) linked to two compounds in the beans, vicine and convicine. An estimated 400 million people have G6PD deficiency, and many have no symptoms and do not know it. Cooking does not remove the compounds.
Fava beans are also one of the oldest crops. Wild seeds about 14,000 years old were found in Israel, and farmers there were growing the domesticated bean about 10,200 years ago. A cup of cooked fava beans (170 g) has 187 calories, 12.9 g of protein, 9.2 g of fiber and 44% of the daily value for folate.
Health benefits of fava beans
The top findings from 18 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Slightly lower “bad” LDL cholesterolDiets built around pulses (beans, chickpeas, lentils and peas) lowered LDL a little (by 0.17 mmol/L across 26 trials). Fava beans were not tested alone.
- ★A weak blood sugar rise after eatingIn nine healthy volunteers, 250 g of cooked, mashed fava beans caused only a weak blood sugar rise (peak 1.02 g/L after 1.5 hours). Insulin rose only slightly.
- ★Lower cholesterol in a small trial of flourIn 40 young men with higher cholesterol, 90 g a day of field bean flour for 30 days lowered total and LDL cholesterol. Levels fell from their starting values in a small trial using flour, not whole beans.
- ★Small Parkinson’s tests: acted like levodopaFava bean pods plus the drug carbidopa worked like levodopa, the standard Parkinson’s medicine, in five of six patients. In another small test, 250 g of cooked beans helped, but three of six had severe involuntary movements, and beans do not replace medicine.
- Population studyLinked to serious anemia in G6PD deficiencyIn 308 Iranian children in hospital with hemolysis (red blood cell breakdown) from G6PD deficiency, an inherited enzyme condition, fava beans caused 85.7%. In Oman, fava beans triggered 51.6% of such episodes in 236 children, and those were more severe.
All 18 studies, strongest evidence first
Diets built around dietary pulses, a group that includes beans, lowered LDL cholesterol by 0.17 mmol/L
Pooled pulses (beans, chickpeas, lentils and peas together), not fava beans alone. Meta-analysis of 26 randomized trials (1,037 people) of at least 3 weeks, with a median dose of 130 g a day, about one serving. The 95% range was 0.09 to 0.25 mmol/L lower. Apolipoprotein B and non-HDL cholesterol did not change, and the authors ask for longer, higher-quality trials.
A diet based on fava beans for 7 days lowered fasting blood glucose and insulin in healthy adults
Randomized crossover trial in 20 healthy volunteers who ate buckwheat-based and fava bean-based diets for 7 days each. The fava bean diet was as filling as their usual diet, raised plasma homocysteine, and supplied more fiber and raised a gut-bacteria metabolite, indole-3-propionic acid. It was small and short, and the diets contained more than beans.
Eating 90 g a day of field bean (Vicia faba) flour for 30 days lowered total and LDL cholesterol from starting levels in young men with higher cholesterol
Study in 40 men aged 18 to 21 with borderline-high or high cholesterol. A control group ate 90 g a day of control flour and the others ate cooked or raw field bean flour. Triglycerides and glucose also fell from their starting values, and HDL cholesterol and glucagon rose. It was small, young men only, and used flour, not whole beans.
Eating fava beans raised plasma dopa from 1,705 to 11,670 pg/mL within an hour in healthy volunteers
Study in 13 healthy volunteers who ate a fixed-sodium diet on day 1 and the same diet plus fava beans on day 2. Plasma dopamine rose nearly 15-fold and urinary dopamine rose too, but urinary sodium fell instead of rising. The authors say the dopa in store-bought beans may be too low to act on the kidney. Each person served as their own comparison.
A meal of fava bean pods plus carbidopa worked like standard levodopa in five of six people with Parkinson’s disease
Single-dose study in 6 patients with Parkinson’s disease and motor fluctuations. Responses began after a mean of 39 minutes and lasted a mean of 104 minutes, and blood L-dopa levels matched those after a standard tablet taken fasting. The bean pod mixture held 0.25% L-dopa by weight. It was a small test of pods with a drug added, not a treatment, and beans do not replace medicine.
250 g of cooked broad beans raised blood levodopa and brought clear improvement in people with Parkinson’s disease, but some had severe dyskinesias
Five healthy volunteers and six patients with Parkinson’s disease ate the beans after 12 hours without treatment. Over the next four hours a substantial clinical improvement was noted, three patients had severe dyskinesias (involuntary movements), and plasma levodopa rose. It was tiny and short, and beans are not a substitute for prescribed medicine.
A 250 g serving of cooked, mashed fava beans caused only a weak blood sugar rise in healthy volunteers
Nine healthy volunteers with a tube in the small intestine ate the dehulled beans, so the researchers could measure starch that was not digested. Of 30.7 g of starch eaten, 6.4 g was recovered at the end of the small intestine, a digestibility of 79.1%. Blood glucose peaked at 1.02 g/L after 1.5 hours and insulin rose only slightly. It was one meal in nine people.
Pasta with 35% fava bean flour kept the low blood sugar and insulin response of plain pasta
Crossover test in 15 healthy volunteers of durum wheat pasta against pasta enriched with 35% faba bean flour, dried at a low or very high temperature. Drying at very high temperature also reduced digestive discomfort and raised reported fullness, without changing food eaten at the next meal. Fava was a flour ingredient, not whole beans, and each test was a single meal.
A meal with texturized fava bean protein gave 4.2% non-heme iron absorption, against 21.7% for beef and 9.2% for cod
Two single-blinded randomized iron-isotope trials in healthy Swedish women aged 18 to 45, each serving as her own control. The percentages in the heading are adjusted values. Iron absorption from the beef meal was 4.2 times higher than from the fava meal, and from the cod meal 2.7 times higher. This tested a meat-alternative protein, not whole beans, and the authors say shifting from meat to it may raise the risk of iron deficiency.
In children with G6PD deficiency admitted to a hospital in Oman, fava beans triggered 51.6% of hemolytic episodes and those were more severe
Hospital study of 236 children over 3 years. Hemoglobin on admission was 4.8 g/dL after fava beans against 6.7 g/dL after other triggers, and the fava group was younger and more often had abdominal pain. The authors call for culturally sensitive diet education where fava beans are a staple food.
Among 308 children in Iran admitted with G6PD-related hemolysis, fava beans were the cause in 85.7%
Single-center descriptive study. Jaundice was the most common complaint (82.5%) and 36.36% of the children received a blood transfusion. It included only children who already had hemolysis, so it cannot give the risk for a person with G6PD deficiency who eats fava beans.
Favism was the most common form of severe hemolytic anemia in Palestinian children in Gaza, and its severity depended on the G6PD variant
Study of children with acute favism, compared with 485 adults and 466 newborns from the general population. Anemia was more severe with the G6PD Med and G6PD Cairo variants than with G6PD A-, and the Cairo variant also had higher bilirubin and mild anemia that lasted up to 4 months after recovery. It shows that G6PD deficiency is not one condition.
A review of case reports found favism was most severe in the youngest children and in pregnant women
Narrative review of case reports and case series, grouped by four age ranges. The amount, quality and ripeness of the beans and the age at onset all shaped the reaction. Death was reported only in infants, visual impairment only in children and kidney failure only in adults. Most cases settled without lasting harm, but hospital care and transfusion were often needed.
G6PD deficiency, the condition behind favism, affects an estimated 400 million people worldwide, and most have no symptoms until a trigger
Systematic review of 280 prevalence estimates from 88 countries. Rates were highest in sub-Saharan Africa, and estimates varied partly because of different testing methods. Most affected people are symptom-free, but oxidative triggers such as certain drugs or infection can cause acute hemolysis.
Each extra 50 g a day of legumes was linked to a 6% lower risk of dying from any cause
Pooled legumes (beans, lentils, chickpeas and peas together), not fava beans alone. Meta-analysis of 32 cohorts with 1,141,793 people and 93,373 deaths. The highest against the lowest intake gave a hazard ratio of 0.94 for all-cause death and 0.91 for stroke death, with no clear link to cardiovascular, coronary or cancer death. The authors rate the certainty low to moderate.
Vicine and convicine, the favism compounds, were highest in fresh green fava seeds and fell as the seeds dried
Lab measurement in two Vicia faba cultivars across pod development. Levels peaked in fresh green seeds (about 80% moisture) and settled once dry matter reached about 40%. The pods held neither compound but were rich in L-dopa. This is plant chemistry, and it does not make any stage of the bean safe for G6PD deficiency.
Across 15 fava bean varieties grown in Sweden, vicine ranged from 403 to 7,014 µg/g
Lab analysis of dry beans. Convicine ranged from 35.5 to 3,121 µg/g, protein from 26 to 33% and iron from 1.8 to 21.3 mg per 100 g. Only one variety had adequate estimated iron availability, and the authors say the choice of variety changes the nutritional gain.
In mice, fava beans lowered the glutathione ratio and raised an oxidative stress marker in both G6PD-deficient and normal animals
Study in mice, not people. Liver gene activity also shifted: 320 transcripts differed between G6PD-deficient and normal mice, and 438 genes changed with fava beans in the deficient mice. It points to oxidative stress as the mechanism of favism.
Who should be careful with fava beans
Most people can eat fava beans freely. Take a little care if one of these applies:
- G6PD deficiency. Avoid fava beans if you have it, including meat alternatives made with fava protein: the Singapore Food Agency says the compounds that trigger favism are not removed by cooking. Boys and men are most often affected, and the condition is most common in parts of Africa, Asia, the Mediterranean and the Middle East, but many people never have symptoms and may not know they have it. Ask a doctor about a G6PD test if you are unsure, and get medical help if you feel unwell after eating them.
- Parkinson’s disease. Fava beans contain L-dopa, and in small studies they changed symptoms, but 3 of 6 patients had severe dyskinesias after 250 g of cooked beans. They are not a substitute for medicine, so talk to your neurologist before using them for symptoms.
- Irritable bowel syndrome or a gassy gut. Monash University says legumes are naturally high in galacto-oligosaccharides and fructans, and that canned or boiled-and-drained legumes tend to be lower. Its page gives no serving size for fava beans, so start small.
How to choose, store and eat fava beans
- Fresh green beans: shell them from the pod and cook them as a green vegetable. Vicine and convicine were highest in fresh green seeds in a lab study, and cooking does not remove them.
- Dried and cooked: the numbers on this page are for boiled beans, with 110 calories and 7.6 g of protein per 100 g. Dry beans are far more concentrated, because cooked beans are about 72% water, so never compare the two directly.
- Frozen: the University of California says there is no approved way to blanch fava beans before freezing, so cook them fully first, about 4 minutes in small batches, then cool them in ice water.
Pick firm, glossy green pods that feel well filled with beans. Oregon State University gives 40 to 45°F with high humidity as the storage range for fresh beans and warns that decay sets in within days above 45°F, so keep them cold.
Sources
- Glucose-6-phosphate dehydrogenase deficiency. MedlinePlus Genetics, U.S. National Library of Medicine.
- The arch enemy of G6PD deficient individuals: fava beans. Singapore Food Agency.
- Glucose-6-phosphate dehydrogenase deficiency. WHO Working Group. Bull World Health Organ. 1989.
- Cappellini MD, Fiorelli G. Glucose-6-phosphate dehydrogenase deficiency. Lancet. 2008.
- Luzzatto L, Arese P. Favism and glucose-6-phosphate dehydrogenase deficiency. N Engl J Med. 2018.
- Beretta A, Manuelli M, Cena H. Favism: clinical features at different ages. Nutrients. 2023.
- Including legumes on a low FODMAP diet. Monash FODMAP blog.
- Kempster PA, Bogetic Z, Secombe JW, et al. Motor effects of broad beans (Vicia faba) in Parkinson’s disease: single dose studies. Asia Pac J Clin Nutr. 1993.
- Rabey JM, Vered Y, Shabtai H, Graff E, Korczyn AD. Improvement of parkinsonian features correlate with high plasma levodopa values after broad bean (Vicia faba) consumption. J Neurol Neurosurg Psychiatry. 1992.
- Burbano C, Cuadrado C, Muzquiz M, Cubero JI. Variation of favism-inducing factors (vicine, convicine and L-DOPA) during pod development in Vicia faba L. Plant Foods Hum Nutr. 1995.
- Fava beans, mature seeds, cooked, boiled, without salt (FDC ID 173753). USDA FoodData Central.
- How to harvest and freeze fava beans. University of California Cooperative Extension.
- Beans, fava. Oregon State University, Oregon Vegetables.
History of fava beans
Fava beans were one of the first crops people grew. At el-Wad on Mount Carmel in Israel, researchers found wild bean seeds about 14,000 years old, which the researchers called the first and, as of 2016, only remains of the crop’s lost wild ancestor. Domestication was documented at Neolithic farming sites in the Lower Galilee about 10,200 years ago.
The plant, Vicia faba, goes by several names. Broad bean, fava bean and faba bean all mean the same species, and fava is the Italian word. In Greece fava means a dish of yellow split peas, so Greeks call broad beans koukia. Small-seeded types grown for animal feed are called field, horse or tic beans.
In ancient Greece and Rome beans were used for voting, with a white bean for yes and a black bean for no. Romans offered beans to the dead during the Lemuria festival, and the family name Fabius is linked to the bean. The Pythagoreans refused to eat beans, and ancient writers guessed at the reason without settling it.
Ful medames, a stew of cooked fava beans with olive oil and cumin, is a national dish of Egypt, and its name is translated as “buried favas”. Archaeologists found a cache of about 2,600 dried fava beans at a late Neolithic site near Nazareth, and the Jerusalem Talmud mentions the dish by the fourth century. In medieval Cairo the beans were cooked overnight in huge pots heated by the fires of a public bath.
Fava beans reached many other kitchens. In Sichuan, China, they are fermented into the chili paste doubanjiang, and in Italy beans are sown on All Souls’ Day and baked into “beans of the dead” cakes.
Sources
- Caracuta V, Weinstein-Evron M, Kaufman D, et al. 14,000-year-old seeds indicate the Levantine origin of the lost progenitor of faba bean. Sci Rep. 2016.
- Vicia faba. Wikipedia.
- Ful medames. Wikipedia.
- Pythagoreanism. Wikipedia.
Frequently asked questions about fava beans
Are fava beans good for you?
For most people, yes. A cup of cooked fava beans (170 g) has 187 calories, 12.9 g of protein, 9.2 g of fiber and 44% of the daily value for folate. The studies on the beans themselves are small and none reaches strong evidence, though pooled pulses lowered LDL cholesterol by 0.17 mmol/L. The big exception is G6PD deficiency, where fava beans can be dangerous.
Who should not eat fava beans?
People with G6PD deficiency should avoid them. In a series of 308 children in Iran with G6PD-related hemolysis, fava beans were the cause in 85.7%, and cooking does not remove the compounds that trigger it. An estimated 400 million people have the deficiency and many do not know it, so ask a doctor about a test if you are unsure.
Can fava beans help with Parkinson’s disease?
Not proven. Fava beans contain L-dopa, and in a small study 250 g of cooked beans improved symptoms in 6 patients, but 3 had severe dyskinesias. A pod mixture plus carbidopa worked like standard levodopa in five of six patients in another single-dose test. These were short experiments, so do not replace or change your medicine without your neurologist.
How much protein do fava beans have?
A fair amount. Cooked fava beans have 7.6 g of protein per 100 g, or 12.9 g in a cup (170 g), and about 30% of their calories come from protein. Its protein quality score is 84 out of 100, limited by methionine and cysteine.
Do fava beans cause gas?
They can, like other beans, though no study here measured gas. Monash University says legumes are naturally high in galacto-oligosaccharides and fructans, and that canned or boiled-and-drained legumes tend to be lower, but it gives no serving for fava beans. If beans bother you, start with small servings.
Are fava beans high in iron?
They have a moderate amount: a cup of cooked beans has 2.55 mg of iron, 14% of the daily value. Absorption may be low: in a trial a meal with texturized fava protein gave 4.2% non-heme iron absorption against 21.7% for beef. That tested a processed protein and not whole beans, so it is a hint and not a measure for the cooked bean.
Are fava beans the same as broad beans?
Yes. Fava beans, broad beans and faba beans are all Vicia faba, and fava is the Italian name. Small-seeded types grown for animal feed are called field, horse or tic beans, and one study here used field bean flour. Favism applies to all of them.
Are fava beans good for blood sugar?
They look gentle, but the evidence is small. A 250 g serving of cooked, mashed fava beans caused a weak blood sugar rise in 9 healthy volunteers, peaking at 1.02 g/L. A 7-day fava bean diet also lowered fasting glucose and insulin in 20 healthy adults. No trial here tested people with diabetes, so check portions with your care team.