Peanuts are not nuts. They are legumes, cousins of beans and lentils. After the flower is fertilized, a stalk pushes into the soil, so the pods ripen underground. That is why the species name, hypogaea, means “under the earth” in Greek.
Raw peanuts have 25.8 g of protein per 100 g, which ranks third among the 132 foods in our database.
The cultivated peanut is a natural hybrid of two wild South American species. They are thought to be Arachis duranensis and Arachis ipaensis. A genome study found patterns that favor a single origin for the crop.
In the northern Peruvian Andes, remains of peanut, squash and cotton date to between 9,240 and 5,500 radiocarbon years ago. The excavators read this as evidence of early use of peanut in the human diet.
Peanut is also the food behind the best-known allergy prevention trial, called LEAP. In LEAP, high-risk babies who ate peanut regularly were far less likely to be allergic by age 5 than babies who avoided it. US guidelines from 2017 now advise giving peanut early.
Peanut is also one of the most common adult food allergies. So the same food can be a risk for one person and protection for another.
Health benefits of peanuts
The top findings from 29 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 →- ★★★Less peanut allergy when babies eat it earlyStarting peanut at 3 to 10 months cut peanut allergy to 0.31 times the risk, across 4 trials in 3,796 babies. In the LEAP trial, 1.9% of high-risk babies with a negative skin test were allergic at age 5, against 13.7% who avoided peanut.
- ★★★Peanut allergy treatment raised the risk of anaphylaxisIn 12 trials of peanut immunotherapy (small, rising doses of peanut protein; median age 8.7 years), severe allergic reactions (anaphylaxis) were 3.12 times as likely. Yet passing a supervised peanut challenge was 12.42 times as likely.
- ★★Slightly higher “good” HDL cholesterolAcross 13 trials of peanut foods, HDL rose by 2.72 mg/dL, while LDL, weight, blood pressure and blood sugar did not change.
- ★★Lower triglycerides, but weight gain in high-risk peoplePooled trials of peanuts found lower triglycerides. People at high risk of heart and metabolic disease gained 0.97 kg.
- ★Lower blood pressure in two trialsIn 151 people, 42 g of peanuts a day for 12 weeks lowered the bottom number (diastolic) by 5.0 mm Hg in higher-risk people. In adults at risk of type 2 diabetes, the top number fell 5.33 mm Hg more than on a low-fat diet.
All 29 studies, strongest evidence first
Early peanut for babies cut peanut allergy to 0.31 times the risk
This meta-analysis of randomized trials asked when babies should first eat allergy-causing foods. For peanut, 4 trials in 3,796 babies started it at 3 to 10 months of age, with high-certainty evidence. Giving several allergy foods at once also lowered food allergy overall. But families were 2.29 times as likely to drop out of that approach.
Peanut immunotherapy more than tripled the risk of anaphylaxis
This meta-analysis pooled 12 randomized trials in 1,041 people, median age 8.7 years, against avoidance or placebo (a dummy treatment). Anaphylaxis, a severe allergic reaction, was 3.12 times as likely, and epinephrine use 2.21 times. Yet after small, rising doses of peanut protein, passing a supervised peanut challenge was 12.42 times as likely. Quality of life did not differ, and the review had no funding.
High-risk babies eating peanut: 1.9% allergic at age 5, against 13.7%
The LEAP trial randomly assigned 640 babies, aged 4 to 11 months, with severe eczema, egg allergy or both. The 1.9% against 13.7% result is for the 530 babies with a negative skin-prick test. In the 98 with a small positive test, it was 10.6% against 35.3%. Serious harmful events did not differ between the groups.
After a year off peanut, early eaters still had less allergy
This follow-up asked all 550 LEAP children to avoid peanut for 12 months after age 5. At 72 months, 4.8% of the group that ate peanut as babies had allergy, against 18.6% of the group that avoided it. That 4.8% was not significantly higher than the 3.6% at 60 months, so the change could be chance. The authors say longer-term effects are not known.
LEAP plus EAT: early peanut cut allergy 75% in main analysis
This analysis pooled individual data from two randomized infant trials, counting every infant in the group they were assigned to. Analyses that assume infants ate the peanut as planned gave 98% and 89% reductions. In the EAT trial alone, only that second kind of analysis showed a clear effect. Protection held across eczema severity, ethnic groups and whether infants were sensitized to peanut at the start, and earlier introduction worked better.
At age 12, 4.4% of early peanut eaters had allergy, against 15.4%
This follow-up covered 497 of the original 640 LEAP children with complete data; the comparison group had avoided peanut as babies. Between ages 6 and 12, children ate or avoided peanut as they liked. Both groups reported long spells without it, yet the protection lasted. Harmful events were uncommon and mostly linked to the food challenge.
Palforzia: 67.2% tolerated at least 600 mg peanut protein, against 4.0%
This late-stage (phase 3) trial compared placebo with AR101, now Palforzia, a peanut-derived powder taken in rising doses for about 24 weeks. The main group was 496 allergic children and teens aged 4 to 17; 551 people aged 4 to 55 took part in all. Over 95% had side effects, severe in 4.3% on the drug, and it was not shown to work in adults 18 and older. It does not cure the allergy, and the maker, Aimmune Therapeutics, funded the trial.
13 trials: peanuts raised HDL cholesterol by 2.72 mg/dL
This meta-analysis pooled randomized trials of peanuts, peanut oil, high-oleic peanuts and peanut sprouts, so not only whole peanuts. Weight, blood pressure, LDL (“bad”) cholesterol, triglycerides and blood sugar did not change. LDL moved by only -3.31 mg/dL (milligrams per deciliter of blood), which could be chance. The rise in HDL (“good”) cholesterol was clearer for peanut oil, high-oleic peanuts, healthy people and trials longer than 12 weeks.
11 peanut trials: lower triglycerides, but high-risk people gained weight
The meta-analysis added a new 6-month trial in 63 healthy adults. There, 25 g a day of skin-roasted peanuts gave lower cholesterol ratios than a peanut-oil control butter. Healthy people had lower total cholesterol and LDL-to-HDL ratios, while people at high cardiometabolic risk gained 0.97 kg. Body fat and BMI (body mass index) did not change, and the Peanut Institute helped fund the work.
Simple harvest and storage steps more than halved blood aflatoxin markers
This study in 20 villages in Guinea compared a package of peanut harvest and storage steps (10 villages) with usual practice (10 villages). Aflatoxin, a mold toxin, was tracked through markers in the blood (albumin adducts) in 600 people. After 5 months of storage, the average was 8.0 pg/mg against 18.7 in the control villages. In the intervention villages, 20% of people had no detectable adducts, against 2%; the study measured exposure, not disease.
Peanuts cut diastolic (lower) blood pressure 5.0 mm Hg at higher risk
In this randomized trial, 151 people ate 42 g of peanuts a day, in different flavors, for 12 weeks. Higher-risk people also had larger drops in cholesterol (12.1 mg/dL) and triglycerides (31.7 mg/dL), while lower-risk people did not. No single flavor changed the results. A variety of flavors went with more weight gain (0.9 kg against 0.5 kg for one flavor), with no significant change in fat mass.
Peanut form made no difference to weight or blood fats
This randomized trial gave 118 adults in Brazil, Ghana and the United States 56 g a day for 4 weeks. They ate raw, roasted, salted or honey-roasted peanuts, or peanut butter. HDL cholesterol rose overall, and people with high blood fats had lower total cholesterol, LDL and triglycerides. The authors conclude that these forms and processing methods do not undo the effects on blood fats.
Peanuts cut systolic pressure 5.33 mm Hg more than a low-fat diet
This randomized trial put 107 adults at risk of type 2 diabetes on calorie-cut diets for 6 months (76 finished). The peanut group ate 35 g of peanuts before two meals a day; systolic pressure is the top number. Weight loss did not differ (a 0.12 kg gap), and neither did HbA1c (long-term blood sugar), fasting glucose or insulin. The Peanut Institute gave a grant for the study.
In older adults, high-oleic peanuts left cholesterol and blood sugar unchanged
This was a crossover trial: 61 people (average age 65, BMI 31) tried both diets in turn. They ate high-oleic peanuts (15 to 20% of energy) or no nuts, for 12 weeks each. Cholesterol, blood sugar and inflammation markers did not change, and body weight rose only 0.5 kg, though energy intake was 10% higher on peanuts. Body composition did not change, and an Australian Research Council grant in partnership with the Peanut Company of Australia funded it.
A nighttime peanut snack did not change fasting glucose
In this crossover trial, 50 adults with raised fasting glucose ate 28 g of dry-roasted peanuts as a nighttime snack for 6 weeks. The comparison was a lower-fat snack with the same calories: whole grain crackers and low-fat cheese. The difference was -0.6 mg/dL, and no heart risk measure differed. The Peanut Institute funded the trial.
Daily peanuts added 1.0 kg, far less than the 3.6 kg predicted
In this 30-week crossover study, 15 normal-weight adults ate about 500 kcal (calories) of peanuts a day. In an 8-week phase with no diet advice, they ate less of other foods, making up for 66% of the peanut energy. When peanuts replaced other fats, weight stayed level. Resting energy use rose 11% after 19 weeks of regular peanuts.
Peanut butter breakfast lowered next-meal blood sugar in women with obesity
In this crossover trial, 15 women with obesity and a high risk of diabetes ate a breakfast with matched carbohydrates. They added 42.5 g of peanut butter, whole skinless peanuts or nothing. Peanut butter also raised gut hormones that signal fullness and lowered the desire to eat. Whole peanuts gave similar effects, but too small to rule out chance.
85 g of ground peanuts blunted the triglyceride rise in overweight men
In this crossover trial, 15 men with overweight or obesity drank a peanut shake or a control shake with the same energy. At 120 minutes, triglycerides were 188.9 against 197.5 mg/dL. Only the control meal lowered blood vessel dilation (-1.2%), and cholesterol, glucose and insulin did not differ. The Peanut Institute supported the study.
Each extra daily ounce of nuts: 22% lower risk of dying
This meta-analysis pooled 20 prospective studies (29 publications) of nuts as a group, with similar results for tree nuts and peanuts. Each extra 28 g (1 oz) a day went with lower risk of coronary heart disease (0.71), cardiovascular disease (0.79) and total cancer (0.85). The link with stroke was not clear (0.93, range 0.83 to 1.05). Results varied between studies.
Nuts 7 or more times a week: 20% lower risk of dying
Two US cohorts of 76,464 women and 42,498 men were followed for up to 30 years, against people who ate no nuts. Deaths from cancer, heart disease and breathing (respiratory) diseases were also lower. The full paper looked at peanuts and tree nuts separately and found similar results. The National Institutes of Health and a tree nut industry foundation funded the work.
Top nut eaters, mostly peanuts: 17 to 21% lower risk of dying
Three cohorts in the US and China, with 14,440 deaths, compared the highest with the lowest fifth of nut intake. In the US cohort, mostly low-income Black and White Americans, about half the nuts eaten were peanuts. The Shanghai cohorts counted peanuts only. The link was mainly with deaths from heart disease.
Women eating peanut butter often had 21% lower type 2 diabetes risk
The Nurses’ Health Study cohort followed 83,818 women for 16 years, and 3,206 developed the disease. The peanut butter result was for 5 or more times a week. Eating 28 g (1 oz) of nuts 5 or more times a week gave a relative risk of 0.73. Five servings of peanut butter a week equals about 140 g of peanuts.
1.8% of US adults have a convincing peanut allergy
This nationally representative survey asked 40,443 adults in 2015 and 2016, and 2.9% reported a peanut allergy. That is about 4.6 million adults, and over 17% of them, more than 800,000, developed it after age 18. About 1 in 5 adults with peanut allergy had an emergency department visit for it in the past year. Answers were self-reported.
Nut-eating mothers without allergy: about a third the child nut-allergy odds
This cohort followed 8,205 children of Nurses’ Health Study II mothers, and 140 had peanut or tree nut allergy. It compared mothers eating peanuts or tree nuts 5 or more times a month around pregnancy with those eating them less than once a month. The odds ratio was 0.31, and the link was not seen in children of mothers who were themselves allergic. Peanuts and tree nuts were counted together, and the study could not prove cause.
In men, frequent nut eating went with 30% lower gallstone risk
This cohort, the Health Professionals Follow-up Study, covered men only; frequent meant 5 or more times a week. It counted 1,833 cases of symptomatic gallstones over 457,305 person-years (people times years followed). Peanuts and other nuts were each linked to lower risk. One serving was 1 ounce, and the study relied on a diet questionnaire.
Peanuts: 58% lower colorectal cancer risk in Taiwanese women, unclear in men
This cohort followed 12,026 men and 11,917 women in Taiwan for about 10 years, with 107 colorectal cancers in all. For eating peanut products often, the risk ratio was 0.42 in women (range 0.21 to 0.84). In men it was 0.73 (range 0.44 to 1.21), a drop that could be chance. The number of cases was small.
Fried or boiled peanuts bound less allergy antibody (IgE) than roasted
This lab test used blood serum from 8 people with peanut allergy and two US peanut varieties. Fried and boiled peanuts had less of the allergen Ara h 1 than dry-roasted ones. They also had less IgE binding to Ara h 1, 2 and 3. The authors suggest this could help explain lower peanut allergy in China, but it is not a study of reactions in people.
Roasted peanuts bound about 90 times more IgE than raw ones
This lab test used blood serum from people with peanut allergy. The peanuts came from two sources, and raw and roasted ones came from the same plants. Browning (the Maillard reaction) made the allergens Ara h 1 and Ara h 2 bind more IgE and resist heat and digestion. It was not a clinical study.
Boiled peanuts held 5.1 µg of resveratrol per gram, roasted 0.055 µg
This lab study measured resveratrol, a plant compound, in store-bought peanut products: 12 boiled samples, 21 roasted samples and 46 peanut butters. Peanut butter held 0.324 µg per gram (µg means micrograms, millionths of a gram). It measured the compound, not health effects.
Who should be careful with peanuts
Most people can eat peanuts freely. Take a little care if one of these applies:
- Peanut allergy. About 1.8% of US adults have a convincing peanut allergy. It can cause anaphylaxis, and avoiding peanut is the rule. The drug Palforzia, approved by FDA in 2020, only reduces reactions to accidental exposure, and it is used alongside a peanut-free diet. For babies the advice runs the other way. NIAID, the US National Institute of Allergy and Infectious Diseases, says in 2017 guidelines to introduce peanut early. If the baby has severe eczema or egg allergy, do it after a doctor’s check.
- Young children. Whole peanuts are a choking hazard. The NHS (the UK health service) says not to give whole nuts under age 5. The American Academy of Pediatrics says to avoid them until about age 4. Spread peanut butter thinly, and ground peanut can go into food.
- Aflatoxin. Peanuts can carry aflatoxin, a mold toxin and known liver carcinogen (cause of cancer). FDA sets an action level of 20 parts per billion for peanuts. The EU limit for peanuts sold to consumers is 2 µg/kg of aflatoxin B1 (4 µg/kg in total). So it is mostly a concern where storage is poor, as in the Guinea villages studied above.
How to choose, store and eat peanuts
- Raw or roasted: our nutrition numbers are for raw peanuts, which hold about 5 mg of sodium per ounce. In a 4-week trial of 118 adults, raw, roasted, salted and honey-roasted peanuts did not differ in their effects on weight or blood fats.
- Boiled: in lab tests, boiled peanuts held 5.1 µg of resveratrol per gram, against 0.055 µg in roasted. Boiled or fried peanuts also bound less allergy antibody than roasted ones. No trial has compared the health effects.
- Peanut butter: in 15 women, 42.5 g at breakfast lowered blood sugar after the next meal. In the Nurses’ Health Study, women who ate it 5 or more times a week had a 21% lower risk of type 2 diabetes.
Check the best-by date and buy only what you will use soon, because nut fat turns rancid over time. Keep peanuts in an airtight container in a cool place. The refrigerator keeps nuts in good quality for about a year. The freezer keeps them for one to three years.
Residues are no reason to skip peanut butter. In USDA (US Department of Agriculture) tests of 705 peanut butter samples in 2022, only one had a residue above the legal limit.
Sources
- Warren C, Lei D, Sicherer S, et al. Prevalence and characteristics of peanut allergy in US adults. J Allergy Clin Immunol. 2021.
- Togias A, Cooper SF, Acebal ML, et al. Addendum guidelines for the prevention of peanut allergy in the United States: report of the National Institute of Allergy and Infectious Diseases-sponsored expert panel. J Allergy Clin Immunol. 2017.
- NIH-sponsored expert panel issues clinical guidelines to prevent peanut allergy. NIAID.
- PALFORZIA. US Food and Drug Administration.
- Foods to avoid giving babies and young children. NHS.
- Building balanced snacks to feed to toddlers. American Academy of Pediatrics, HealthyChildren.org.
- Action levels for poisonous or deleterious substances in human food and animal feed. US Food and Drug Administration.
- Commission Regulation (EU) 2023/915 on maximum levels for certain contaminants in food. Annex I, section 1.1. 2023.
- Liu Y, Wu F. Global burden of aflatoxin-induced hepatocellular carcinoma: a risk assessment. Environ Health Perspect. 2010.
- Turner PC, Sylla A, Gong YY, et al. Reduction in exposure to carcinogenic aflatoxins by postharvest intervention measures in west Africa: a community-based intervention study. Lancet. 2005.
- McKiernan F, Lokko P, Kuevi A, et al. Effects of peanut processing on body weight and fasting plasma lipids. Br J Nutr. 2010.
- Sobolev VS, Cole RJ. trans-Resveratrol content in commercial peanuts and peanut products. J Agric Food Chem. 1999.
- Beyer K, Morrow E, Li XM, et al. Effects of cooking methods on peanut allergenicity. J Allergy Clin Immunol. 2001.
- Reis CE, Ribeiro DN, Costa NM, et al. Acute and second-meal effects of peanuts on glycaemic response and appetite in obese women with high type 2 diabetes risk: a randomised cross-over clinical trial. Br J Nutr. 2013.
- Jiang R, Manson JE, Stampfer MJ, et al. Nut and peanut butter consumption and risk of type 2 diabetes in women. JAMA. 2002.
- Going nutty over advice for preserving nutmeats? National Center for Home Food Preservation. 2014.
- Nuts need food safety too. University of Illinois Extension. 2025.
- Pesticide Data Program annual summary, calendar year 2022. USDA Agricultural Marketing Service.
History of peanuts
Peanuts began in South America. Their wild relatives grow east of the Andes, around Peru, Bolivia, Argentina and Brazil. The cultivated peanut arose from a hybrid of two of them whose chromosomes doubled, which made it fertile. A 2019 genome study favors a single origin for the crop and for its wild counterpart, Arachis monticola.
People were eating peanuts a very long time ago. In a dry forest valley of northern Peru, remains of peanut, squash and cotton were radiocarbon dated to between 9,240 and 5,500 years ago. The excavators saw them as evidence that gardening in the Andes took root by about 10,000 years ago.
When Spanish conquistadors reached Mexico, they found peanuts for sale in the market of Tenochtitlan. The Nahuatl name was tlālcacahuatl, which gave Spanish its word cacahuate.
European traders spread the crop around the world. In West Africa it largely replaced the Bambara groundnut, a related crop whose pods also ripen underground. The American name “goober” reached the United States through Kikongo, and the British call peanuts monkey nuts.
In the United States, peanuts were a colonial garden crop. From 1870 they were mostly animal feed, until eating them grew in the 1930s. The USDA ran a program in the late 19th and early 20th centuries to encourage growing and eating them.
George Washington Carver promoted peanuts as a rotation crop in the South, where repeated cotton planting had worn out the soil. He did not invent peanut butter, though.
Peanut butter has its own story. Marcellus Gilmore Edson of Montreal patented a way to make it from roasted peanuts in 1884. John Harvey Kellogg patented a version made with boiled peanuts in 1898. In 1922 the chemist Joseph Rosefield found a way to keep the oil from separating, which led to Skippy in 1932.
Another peanut paste has saved lives. In 1996 the French nutritionist André Briend and the engineer Michel Lescanne invented Plumpy’Nut. It is a paste of peanuts, oil, milk powder, sugar, vitamins and minerals that treats severe malnutrition in children at home. It needs no water or refrigeration and keeps for two years.
Sources
- Bertioli DJ, Jenkins J, Clevenger J, et al. The genome sequence of segmental allotetraploid peanut Arachis hypogaea. Nat Genet. 2019.
- Dillehay TD, Rossen J, Andres TC, Williams DE. Preceramic adoption of peanut, squash, and cotton in northern Peru. Science. 2007.
- Briend A, Lescanne M, et al. Ready-to-use therapeutic food for treatment of marasmus. Lancet. 1999.
- Peanut. Wikipedia.
- Peanut butter. Wikipedia.
- Plumpy’Nut. Wikipedia.
Frequently asked questions about peanuts
Are peanuts good for you?
For most people, yes, with one big exception: peanut allergy. Per 100 g, raw peanuts have 25.8 g of protein, 8.5 g of fiber and 49.2 g of fat. A 1 oz (28 g) serving gives 36% of the Daily Value for copper.
The biggest nut eaters (mostly peanuts) in US and Chinese cohorts had a 17 to 21% lower risk of dying. That is a link, not proof, and peanut trials on cholesterol and blood pressure were mixed.
Are peanuts nuts?
No, peanuts are legumes, related to beans and lentils, and the pods ripen underground. Many studies still group them with nuts. In the Nurses’ Health Study and Health Professionals cohorts, peanuts and tree nuts gave similar results for the risk of dying. Studies of allergy often count peanuts and tree nuts together too, as one cohort of mothers did.
How many peanuts can you eat a day?
No study here sets an ideal amount, but trials used 28 g a day as a nighttime snack for 6 weeks. Others used 42 g a day for 12 weeks and 56 g a day for 4 weeks.
Raw peanuts have 161 calories in 1 oz (28 g). In a 30-week study of 15 adults, people ate less other food to make up for 66% of the peanut energy. If you have peanut allergy, no amount is safe.
Are peanuts good for weight loss?
Peanuts did not slow weight loss in the one trial that tested it, but no trial shows they cause it. In it, 107 adults ate a calorie-cut diet for 6 months. Eating 35 g of peanuts before two meals a day gave the same weight loss as a low-fat diet.
People given about 500 kcal of peanuts a day gained 1.0 kg, against 3.6 kg predicted. A meta-analysis found people at high cardiometabolic risk gained 0.97 kg on peanuts.
Are boiled peanuts healthier than roasted?
Nobody has tested that in people. In lab tests, boiled peanuts held 5.1 µg of resveratrol per gram, against 0.055 µg in roasted. Boiled or fried peanuts also bound less allergy antibody than roasted ones. These are lab measurements, not health results, and they do not make boiled peanuts safe for someone with peanut allergy.
When can babies eat peanuts?
In the first year, and often earlier than parents expect. NIAID’s 2017 guidelines say 4 to 6 months for infants with severe eczema, egg allergy or both, after testing as a clinician advises. For mild to moderate eczema, they say around 6 months.
A meta-analysis found that peanut introduced at 3 to 10 months lowered peanut allergy to 0.31 times the risk. Give it as thinned peanut butter or ground peanut, never whole peanuts, which are a choking risk.
Are peanuts high in protein?
Yes, they are among the highest of the foods we track. Raw peanuts have 25.8 g of protein per 100 g, or 7.3 g in 1 oz, third among 132 foods in our database. Lysine is the limiting amino acid (the scarcest relative to need), with a protein completeness score of 70 out of 100.
Is peanut butter as healthy as peanuts?
Probably similar, though few studies compare them. In 118 adults, peanut butter and whole peanuts did not differ in their effects on weight or blood fats over 4 weeks. In 15 women, peanut butter at breakfast lowered blood sugar after the next meal; whole peanuts gave similar effects that could be chance. Women who ate peanut butter 5 or more times a week had a 21% lower risk of type 2 diabetes in a large cohort.