What does the research show about nuts?

Nuts

Two pooled analyses of feeding trials found nuts lowered LDL cholesterol, by about 5 mg/dL per daily ounce, and ApoB. Cohorts link more nuts to less heart disease and death, and nut-feeding trials found no change in body weight. Peanut allergy affects about 1.8% of US adults, and early peanut feeding cut peanut allergy in high-risk infants.

Add to Bio HackChecked 2026-11-13

Status: A food, not a regulated health product. The FDA allows a qualified health claim that "scientific evidence suggests but does not prove that eating 1.5 ounces per day of most nuts" as part of a diet low in saturated fat and cholesterol "may reduce the risk of heart disease" [1], and lists a qualified claim for ground peanuts and reduced risk of developing peanut allergy [2]. Peanuts and tree nuts are among the nine major food allergens under US law [3].
Also called: tree nuts, peanuts, almonds, walnuts, pistachios, cashews, hazelnuts, pecans, macadamia nuts, Brazil nuts, mixed nuts, peanut butter, nut butter
Studied for: cholesterol, LDL, heart health, heart attack and stroke, longevity, weight loss, blood sugar, diabetes, inflammation, peanut allergy prevention in infants

Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on

Shown to help6

StrongShown to lower LDL cholesterol by about 4.8 mg/dL per daily ounce of tree nuts, and by 10.2 mg/dL at about 67 g a day, along with ApoB.
ModerateShown to lower HbA1c by 0.07 percentage points and fasting glucose slightly in people with type 2 diabetes, in one meta-analysis of short trials.
LimitedLinked to 21% to 29% lower cardiovascular disease per daily serving in cohort meta-analyses. Stroke was not significantly linked.
LimitedOne trial found 28% fewer heart attacks, strokes or heart deaths with a Mediterranean diet plus mixed nuts than with advice to cut dietary fat.
LimitedLinked to 17% to 22% lower death from any cause per daily serving of nuts in two cohort meta-analyses, with similar results for tree nuts and peanuts.
LimitedOne trial in infants at high risk found peanut allergy at age 5 in 1.9% of those fed peanut and 13.7% of those who avoided it.

Reported risks1

LimitedA national survey estimated convincing peanut allergy in 1.8% and tree nut allergy in 1.2% of US adults. The FDA lists both among nine major food allergens.Common

What it was studied for, and what was found

Shown to help6

Strong

LDL cholesterol and ApoB

Shown to lower LDL cholesterol by about 4.8 mg/dL per daily ounce of tree nuts, and by 10.2 mg/dL at about 67 g a day, along with ApoB.

Compared with control arms without nuts [4]; control diets the abstract does not describe [5]

The numbers and sources

Effect: Per 1 oz (28.4 g) serving a day, tree nuts lowered total cholesterol by 4.7 mg/dL (95% CI 4.0 to 5.3), LDL cholesterol by 4.8 mg/dL (95% CI 4.2 to 5.5), ApoB by 3.7 mg/dL (95% CI 2.3 to 5.2) and triglycerides by 2.2 mg/dL (95% CI 0.5 to 3.8). HDL cholesterol, apolipoprotein A1 and blood pressure did not change significantly. Effects were stronger at 60 g a day or more and did not differ by nut type. ApoB fell more in people with type 2 diabetes (11.5 mg/dL) than in healthy people (2.5 mg/dL) [4]. Pooled individual data from 25 trials found a mean 67 g a day lowered total cholesterol by 10.9 mg/dL (5.1%) and LDL cholesterol by 10.2 mg/dL (7.4%). Triglycerides fell 20.6 mg/dL in people starting at 150 mg/dL or higher and not in others [5].
Population: 2,582 adults without cardiovascular disease in 61 trials of 3 to 26 weeks [4]. 583 adults with normal or high cholesterol not on lipid-lowering drugs, in 25 trials in 7 countries [5].
Sources: [4], [5]
Caveats: Trials were short and many are shared between the two analyses. Effects were largest in people with higher starting LDL cholesterol and lower body mass index [5].

Limited

Heart disease, in cohorts

Linked to 21% to 29% lower cardiovascular disease per daily serving in cohort meta-analyses. Stroke was not significantly linked.

Compared with people eating 28 g a day less [6]; people eating one serving a day less, and the lowest intake group [7]

The numbers and sources

Effect: Per 28 g a day more, nuts were linked to lower coronary heart disease (RR 0.71, 95% CI 0.63 to 0.80) and cardiovascular disease (RR 0.79, 95% CI 0.70 to 0.88), and not significantly to stroke (RR 0.93, 95% CI 0.83 to 1.05). Results were similar for tree nuts and peanuts [6]. Per serving a day, ischemic heart disease (RR 0.72) and cardiovascular disease (RR 0.71) were lower, and stroke did not differ between the highest and lowest intakes (RR 0.91, 95% CI 0.81 to 1.02) [7].
Population: 20 prospective studies [6]. 18 prospective studies with 8,862 cardiovascular cases [7].
Sources: [6], [7]
Caveats: Observational. People who eat nuts may differ in diet, exercise and income, so confounding is possible, and people who are unwell may eat fewer nuts. Heterogeneity was moderate [6].

Limited

Heart attack and stroke, in a diet trial with nuts

One trial found 28% fewer heart attacks, strokes or heart deaths with a Mediterranean diet plus mixed nuts than with advice to cut dietary fat.

Compared with a control diet with advice to reduce dietary fat [8]

The numbers and sources

Effect: Over a median 4.8 years, major cardiovascular events occurred in 3.4% of the Mediterranean diet with nuts group and 4.4% of the control group (HR 0.72, 95% CI 0.54 to 0.95) [8].
Population: 7,447 Spanish adults aged 55 to 80 at high cardiovascular risk, 57% women [8].
Sources: [8]
Caveats: Nuts were one part of a whole diet change, so the trial does not isolate nuts. The original report was withdrawn after randomization problems, and these are reanalyzed estimates [8].
Why limited: This rests on one trial, of 7,447 people. Strength counts independent studies that agree, so one trial is limited at any size.

Limited

Death from any cause, in cohorts

Linked to 17% to 22% lower death from any cause per daily serving of nuts in two cohort meta-analyses, with similar results for tree nuts and peanuts.

Compared with people eating 28 g a day less [6]; people eating one serving a day less, and the lowest intake group [7]

The numbers and sources

Effect: Per 28 g a day more, death from any cause was lower (RR 0.78, 95% CI 0.72 to 0.84), as were total cancer (RR 0.85) and deaths from respiratory disease, diabetes and infections [6]. Per serving a day, death from any cause was lower (RR 0.83, 95% CI 0.76 to 0.91), and 0.85 (95% CI 0.79 to 0.91) for the highest against the lowest intake [7].
Population: 15 cohort estimates for death from any cause [6]. 18 prospective studies with 48,818 deaths [7].
Sources: [6], [7]
Caveats: Observational, open to confounding and reverse causation. Heterogeneity was high (I² 66%) [6].

Moderate

Blood sugar in type 2 diabetes

Shown to lower HbA1c by 0.07 percentage points and fasting glucose slightly in people with type 2 diabetes, in one meta-analysis of short trials.

Compared with diets with the same calories without tree nuts [12]

The numbers and sources

Effect: A median 56 g a day of tree nuts lowered HbA1c (MD -0.07%, 95% CI -0.10 to -0.03) and fasting glucose (MD -0.15 mmol/L, 95% CI -0.27 to -0.02). Fasting insulin and HOMA-IR did not change significantly [12].
Population: 450 people with diabetes in 12 randomized trials of 3 weeks or more [12].
Sources: [12]
Caveats: The reviewers describe most trials as short and of poor quality [12].

LimitedStudied in children

Peanut allergy in high-risk infants

One trial in infants at high risk found peanut allergy at age 5 in 1.9% of those fed peanut and 13.7% of those who avoided it.

Compared with avoiding peanut until 60 months of age [14]

The numbers and sources

Effect: In infants with a negative skin test at the start, peanut allergy at 60 months was 13.7% with avoidance and 1.9% with regular peanut consumption (P < 0.001). In infants with a small positive skin test, it was 35.3% and 10.6% (P = 0.004). Serious adverse events did not differ significantly between groups [14]. The FDA lists a qualified health claim for ground peanuts and reduced risk of developing peanut allergy [2].
Population: 640 infants aged 4 to 11 months with severe eczema, egg allergy or both [14].
Sources: [14], [2]
Caveats: One trial in infants at high risk. It does not test nuts in older children or adults.

Not shown to help4

Moderate

Blood pressure

Not shown to lower blood pressure in a meta-analysis of 61 tree nut trials.

Compared with control arms without nuts [4]

The numbers and sources

Effect: Tree nut intake had no statistically significant effect on blood pressure, while cholesterol, ApoB and triglycerides fell [4].
Population: 2,582 adults without cardiovascular disease in 61 trials [4].
Sources: [4]
Caveats: Trials were designed around blood lipids, and the abstract gives no blood pressure estimate.

Strong

Body weight

Not shown to change body weight, body mass index or waist size in two meta-analyses of nut-feeding trials, either up or down.

Compared with control diets [9]; control groups the abstract does not describe [10]

The numbers and sources

Effect: Across 33 trials, diets with nuts did not differ from control diets in body weight (WMD -0.47 kg, 95% CI -1.17 to 0.22), BMI or waist circumference [9]. Across 55 trials, body weight did not change with or without instructions to swap nuts for other foods. Body fat percentage fell slightly when swap instructions were given (SMD -0.32, 95% CI -0.61 to -0.03) [10].
Population: 33 randomized trials [9]. Adults in 55 trials lasting more than 3 weeks [10].
Sources: [9], [10]
Caveats: Trials were short. Many included instructions to replace other foods with nuts, which is not the same as adding nuts on top of a usual diet [10].

Limited

Type 2 diabetes, in cohorts

Not linked to type 2 diabetes in cohorts once body weight is accounted for. One analysis linked peanut butter to 13% lower risk.

Compared with the lowest intake group [11]; people eating one serving a day less [7]

The numbers and sources

Effect: Total nut intake was not significantly linked to type 2 diabetes in cohort or cross-sectional studies. Peanut butter was linked to lower risk (RR 0.87, 95% CI 0.77 to 0.98), and peanuts and tree nuts were not [11]. Per serving a day, the link with diabetes (RR 0.80) disappeared after adjusting for body mass index (RR 1.03, 95% CI 0.91 to 1.16) [7].
Population: 5 prospective and 3 cross-sectional studies [11]. 18 prospective studies with 12,655 diabetes cases [7].
Sources: [11], [7]
Caveats: Observational. The certainty of evidence was rated very low for every exposure [11].

Strong

Inflammation and blood vessel function

Not shown to lower C-reactive protein in two meta-analyses of nut trials. Blood vessel widening, a measure of vessel function, improved in one.

Compared with control conditions the abstract does not describe [13]; control arms without nuts [4]

The numbers and sources

Effect: Across 25 trials, nuts made no significant difference to C-reactive protein (WMD -0.01 mg/L, 95% CI -0.06 to 0.03) or other inflammation markers. Flow-mediated dilation rose 0.79% (95% CI 0.35 to 1.23) across 8 trials [13]. Tree nuts had no significant effect on C-reactive protein in 61 trials [4].
Population: 32 randomized trials in adults, 652 participants for vessel function [13]. 2,582 adults in 61 trials [4].
Sources: [13], [4]
Caveats: The authors note the C-reactive protein result may have been influenced by two studies [13].

Amounts studied

The lipid meta-analysis standardized results to one 1 oz (28.4 g) serving a day, over 3 to 26 weeks, and found larger effects at 60 g a day or more [4]. The pooled lipid trials averaged 67 g a day [5]. Cohort analyses used 28 g a day [6] or one serving a day [7] as the unit. The Mediterranean diet trial gave participants free mixed nuts for a median 4.8 years [8]. The diabetes trials used a median 56 g a day [12]. The infant trial fed peanut regularly from 4 to 11 months of age until 60 months [14]. The FDA qualified claim names 1.5 ounces a day [1].

Risks

Reported risks1

LimitedCommon

Peanut and tree nut allergy

A national survey estimated convincing peanut allergy in 1.8% and tree nut allergy in 1.2% of US adults. The FDA lists both among nine major food allergens.

The numbers and sources

How common: Common: between 1 in 100 and 1 in 10 people.
Effect: Among 40,443 US adults surveyed, convincing peanut allergy was estimated at 1.8% (95% CI 1.7 to 1.9) and tree nut allergy at 1.2% (95% CI 1.1 to 1.3). Among adults with any food allergy, 51.1% had experienced a severe reaction [15]. Peanuts and tree nuts are among the nine major food allergens identified by US law [3].
Population: 40,443 US adults, mean age 46.6 [15].
Sources: [15], [3]
Caveats: Self-reported symptoms, judged convincing by symptom type, without allergy testing [15].

Checked, no increase found1

LimitedStudied in men

Diverticulitis

Not linked to more diverticulitis or diverticular bleeding in one cohort of 47,228 men followed for 18 years.

The numbers and sources

How common: How often is not known: the sources give no rate.
Effect: Men eating nuts at least twice a week had no higher risk of diverticulitis than men eating them less than once a month (HR 0.80, 95% CI 0.63 to 1.01, P for trend 0.04), and nuts were not linked to diverticular bleeding or uncomplicated diverticulosis [16].
Population: 47,228 US men aged 40 to 75, with 801 cases of diverticulitis [16].
Sources: [16]
Caveats: Observational, men only.

Claims tested and not found

That eating nuts leads to weight gain. Two meta-analyses of nut-feeding trials found no change in body weight against control diets [9][10].
That nuts trigger diverticulitis. In 47,228 men followed for 18 years, eating nuts twice a week or more was not linked to more diverticulitis [16].
That nuts lower inflammation measured by C-reactive protein. Two meta-analyses of trials found no significant change [13][4].

Mediterranean diet

Sources

U.S. Food and Drug Administration. Qualified Health Claims: Letter of Enforcement Discretion. Nuts and Coronary Heart Disease. 2003. http://wayback.archive-it.org/7993/20171114183649/https://www.fda.gov/Food/IngredientsPackagingLabeling/LabelingNutrition/ucm072926.htm
U.S. Food and Drug Administration. Qualified Health Claims: Letters of Enforcement Discretion. 2024. https://www.fda.gov/food/food-labeling-nutrition/qualified-health-claims-letters-enforcement-discretion
U.S. Food and Drug Administration. Food Allergies. 2026. https://www.fda.gov/food/nutrition-food-labeling-and-critical-foods/food-allergies
Del Gobbo LC, Falk MC, Feldman R, et al. Effects of tree nuts on blood lipids, apolipoproteins, and blood pressure: systematic review, meta-analysis, and dose-response of 61 controlled intervention trials. The American Journal of Clinical Nutrition. 2015. https://doi.org/10.3945/ajcn.115.110965
Sabaté J, Oda K, Ros E. Nut consumption and blood lipid levels: a pooled analysis of 25 intervention trials. Archives of Internal Medicine. 2010. https://doi.org/10.1001/archinternmed.2010.79
Aune D, Keum N, Giovannucci E, et al. Nut consumption and risk of cardiovascular disease, total cancer, all-cause and cause-specific mortality: a systematic review and dose-response meta-analysis of prospective studies. BMC Medicine. 2016. https://doi.org/10.1186/s12916-016-0730-3
Luo C, Zhang Y, Ding Y, et al. Nut consumption and risk of type 2 diabetes, cardiovascular disease, and all-cause mortality: a systematic review and meta-analysis. The American Journal of Clinical Nutrition. 2014. https://doi.org/10.3945/ajcn.113.076109
Estruch R, Ros E, Salas-Salvadó J, et al. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts. New England Journal of Medicine. 2018. https://doi.org/10.1056/nejmoa1800389
Flores-Mateo G, Rojas-Rueda D, Basora J, et al. Nut intake and adiposity: meta-analysis of clinical trials. The American Journal of Clinical Nutrition. 2013. https://doi.org/10.3945/ajcn.111.031484
Guarneiri LL, Cooper JA. Intake of Nuts or Nut Products Does Not Lead to Weight Gain, Independent of Dietary Substitution Instructions: A Systematic Review and Meta-Analysis of Randomized Trials. Advances in Nutrition. 2021. https://doi.org/10.1093/advances/nmaa113
Becerra-Tomás N, Paz-Graniel I, Hernández-Alonso P, et al. Nut consumption and type 2 diabetes risk: a systematic review and meta-analysis of observational studies. The American Journal of Clinical Nutrition. 2021. https://doi.org/10.1093/ajcn/nqaa358
Viguiliouk E, Kendall CW, Blanco Mejia S, et al. Effect of tree nuts on glycemic control in diabetes: a systematic review and meta-analysis of randomized controlled dietary trials. PLoS ONE. 2014. https://doi.org/10.1371/journal.pone.0103376
Neale EP, Tapsell LC, Guan V, Batterham MJ. The effect of nut consumption on markers of inflammation and endothelial function: a systematic review and meta-analysis of randomised controlled trials. BMJ Open. 2017. https://doi.org/10.1136/bmjopen-2017-016863
Du Toit G, Roberts G, Sayre PH, et al. Randomized trial of peanut consumption in infants at risk for peanut allergy. New England Journal of Medicine. 2015. https://doi.org/10.1056/nejmoa1414850
Gupta RS, Warren CM, Smith BM, et al. Prevalence and Severity of Food Allergies Among US Adults. JAMA Network Open. 2019. https://doi.org/10.1001/jamanetworkopen.2018.5630
Strate LL, Liu YL, Syngal S, Aldoori WH, Giovannucci EL. Nut, corn, and popcorn consumption and the incidence of diverticular disease. JAMA. 2008. https://doi.org/10.1001/jama.300.8.907

Everything in the library

Shown to help6

Reported risks1

What it was studied for, and what was found

Shown to help6

Not shown to help4

Amounts studied

Risks

Reported risks1

Checked, no increase found1

Claims tested and not found

Related

Sources