Examining the potential health benefits of pistachios Original paper

In this meta-analysis of randomized controlled trials, eating pistachios was found to improve systolic blood pressure, triglycerides, and fasting blood glucose.

This Study Summary was published on August 23, 2022.


Pistachios are high in unsaturated fat, fiber, and various vitamins and minerals. Based on these characteristics, it seems reasonable to suspect that eating pistachios might be good for your health.

Nutrients in pistachios

Per 100 grams of pistachios

The potential benefits of pistachios are backed up by both observational and interventional studies on nuts in general, which suggest a variety of benefits for cardiometabolic health.[1] However, all nuts are not identical and may not have the same health effects. What does the clinical trial evidence say about the effects of pistachios specifically?

The study

This meta-analysis of 17 randomized controlled trials examined the effects of eating pistachios on markers of metabolic health. The trials included a total of 940 people with an average age range of 22–60. The participants had dyslipidemia (4 trials), metabolic syndrome (2 trials), prediabetes (1 trial), erectile dysfunction (1 trial), or were considered to be “healthy” (6 trials).

The trials lasted 2–24 weeks and tested pistachio intakes of 25–126 grams per day. The participants followed various diets, including their usual diet, low-fat diets, and American Heart Association dietary guidelines. In most trials, pistachios replaced foods with a similar caloric content, like pretzels, potato chips, cookies, fats, and oils.

The examined outcomes were BMI (7 trials), waist circumference (5 trials), systolic blood pressure (SBP, 8 trials), diastolic blood pressure (DBP, 8 trials), triglycerides (15 trials), HDL-C (13 trials), and fasting blood glucose (8 trials).

The results

Pistachio consumption reduced systolic blood pressure (-2.89 mmHg), triglycerides (-18.76 mg/dL), and fasting blood glucose, (-3.62 mg/dL) and increased HDL (+1.43 mg/dL). Pistachios did not alter BMI, waist circumference, or diastolic blood pressure.

Effects of pistachios on outcomes

Outcome measure# of trialsResultHeterogeneity
Waist circumference
Systolic blood pressure
-2.89 mmHg
Diastolic blood pressure
-16.76 mg/dL
+1.43 mg/dL
Fasting blood glucose
-3.62 mg/dL

The big picture

Based on this meta-analysis, eating pistachios may lead to improvements in metabolic health and reduce risk factors for cardiovascular disease.

Researchers noted a reduction in triglyceride levels associated with pistachio consumption. This could be related to the fact that pistachios were often consumed in place of higher carbohydrate, lower fiber foods, which tend to raise triglycerides compared to higher fiber, higher fat foods like pistachios.[2] In general, most triglycerides are carried in the blood by atherogenic (plaque forming) lipoproteins (e.g., VLDL), meaning that reducing triglyceride levels, all else being equal, is likely to reduce the risk of cardiovascular disease.[3]

This study did not assess changes in LDL-C, but existing evidence suggests that pistachios can also reduce levels of this blood lipid. A 2020 network meta-analysis of RCTs found that eating pistachios reduced LDL levels by 6.6 mg/dL (0.17 mmol/L), an effect similar to, and even trending better than, eating several other types of tree nuts (walnuts, hazelnuts, cashews, and almonds).[4] LDL-C, like triglycerides, is a marker for the number of atherogenic lipoproteins in the bloodstream.[3] Pistachios reducing this lipid is another mechanism that could explain why eating pistachios may reduce the risk of cardiovascular disease.

Pistachios were reported to reduce systolic blood pressure by 2.89 mmHg. This may be attributable, in part, to the fact that pistachios are a good source of potassium (containing just under 300 mg of potassium per ounce), which has a well established blood-pressure-reducing effect.[5] A 2.89 mmHg reduction is small, but for people with high blood pressure, reducing systolic blood pressure by even 5 mmHg seems to lower the risk of cardiovascular disease.[6] It should be noted that none of the assessed trials were conducted specifically on people with high blood pressure. It’s possible pistachios may reduce blood pressure more among people with hypertension, similar to how strategies like sodium restriction and potassium supplementation[7] function in people with hypertension, but this remains speculative.

There was a decrease in fasting glucose levels with pistachio intake, indicating an improvement in blood sugar regulation. At least one observational study, although it did not look at pistachios specifically, also seems consistent with the theory that pistachios may be helpful for glycemic control. That study, a prospective cohort study involving 83,818 women, found that eating an ounce of nuts at least five times per week was associated with a 29% lower risk of developing type 2 diabetes after adjusting for various potential confounders.[8] Interestingly, this protective association was present regardless of BMI category (less than 25, 25-29, and at least 30). The mechanisms through which nuts like pistachios might benefit blood sugar control are unclear, but possibilities include the ability to reduce ceramides,[9] increase adiponectin,[10] and alter the gut microbiota.[11]

Unfortunately, the existing research is not without shortcomings, as noted by the investigators in a risk-of-bias assessment. In most of the trials, it was unclear how investigators concealed the allocation of participants into study groups. This introduces the potential for differences between groups, which can affect study results.[12] Furthermore, all trials were considered to be at high risk of having incomplete outcome data and selective reporting.

Finally, there are also some potential downsides to pistachios. Pistachios are notably high in FODMAPs, a class of poorly metabolized carbohydrates that often cause gastrointestinal problems in certain people.[13] Eating pistachios, especially in large quantities, may result in adverse effects like abdominal pain and bloating in people sensitive to FODMAPs. Nuts with lower FODMAP levels include macadamia nuts, walnuts, and pecans. Another potential concern regarding pistachio intake is nut allergy. While pistachio allergies only affect a small percentage of the population (possibly less than 2%, although rates vary globally), people with an allergy can experience extreme reactions upon exposure, including anaphylaxis.[14]

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This Study Summary was published on August 23, 2022.


  1. ^Kim Y, Keogh J, Clifton PMNuts and Cardio-Metabolic Disease: A Review of Meta-Analyses.Nutrients.(2018-Dec-06)
  2. ^Laufs U, Parhofer KG, Ginsberg HN, Hegele RAClinical review on triglycerides.Eur Heart J.(2020-01-01)
  3. ^Cho DS, Woo S, Kim S, Byrne CD, Kong JH, Sung KCEstimation of plasma apolipoprotein B concentration using routinely measured lipid biochemical tests in apparently healthy Asian adults.Cardiovasc Diabetol.(2012-May-18)
  4. ^Liu K, Hui S, Wang B, Kaliannan K, Guo X, Liang LComparative effects of different types of tree nut consumption on blood lipids: a network meta-analysis of clinical trials.Am J Clin Nutr.(2020-01-01)
  5. ^Filippini T, Naska A, Kasdagli MI, Torres D, Lopes C, Carvalho C, Moreira P, Malavolti M, Orsini N, Whelton PK, Vinceti MPotassium Intake and Blood Pressure: A Dose-Response Meta-Analysis of Randomized Controlled Trials.J Am Heart Assoc.(2020-06-16)
  6. ^Blood Pressure Lowering Treatment Trialists' CollaborationPharmacological blood pressure lowering for primary and secondary prevention of cardiovascular disease across different levels of blood pressure: an individual participant-level data meta-analysisLancet.(2021 May 1)
  7. ^Ndanuko RN, Tapsell LC, Charlton KE, Neale EP, Batterham MJDietary Patterns and Blood Pressure in Adults: A Systematic Review and Meta-Analysis of Randomized Controlled TrialsAdv Nutr.(2016 Jan 15)
  8. ^Jiang R, Manson JE, Stampfer MJ, Liu S, Willett WC, Hu FBNut and peanut butter consumption and risk of type 2 diabetes in women.JAMA.(2002-Nov-27)
  9. ^Tuccinardi D, Farr OM, Upadhyay J, Oussaada SM, Klapa MI, Candela M, Rampelli S, Lehoux S, Lázaro I, Sala-Vila A, Brigidi P, Cummings RD, Mantzoros CSMechanisms underlying the cardiometabolic protective effect of walnut consumption in obese people: A cross-over, randomized, double-blind, controlled inpatient physiology study.Diabetes Obes Metab.(2019-09)
  10. ^Gulati S, Misra A, Pandey RM, Bhatt SP, Saluja SEffects of pistachio nuts on body composition, metabolic, inflammatory and oxidative stress parameters in Asian Indians with metabolic syndrome: a 24-wk, randomized control trial.Nutrition.(2014-Feb)
  11. ^Ukhanova M, Wang X, Baer DJ, Novotny JA, Fredborg M, Mai VEffects of almond and pistachio consumption on gut microbiota composition in a randomised cross-over human feeding study.Br J Nutr.(2014-Jun-28)
  12. ^Nunan D, Heneghan C, Spencer EACatalogue of bias: allocation bias.BMJ Evid Based Med.(2018-02)
  13. ^Bellini M, Tonarelli S, Mumolo MG, Bronzini F, Pancetti A, Bertani L, Costa F, Ricchiuti A, de Bortoli N, Marchi S, Rossi ALow Fermentable Oligo- Di- and Mono-Saccharides and Polyols (FODMAPs) or Gluten Free Diet: What Is Best for Irritable Bowel Syndrome?Nutrients.(2020-Nov-01)
  14. ^Costa J, Silva I, Vicente AA, Oliveira MBPP, Mafra IPistachio nut allergy: An updated overview.Crit Rev Food Sci Nutr.(2019)