pistachio nuts

What are pistachio nuts

Pistachio (Pistacia vera L.), a member of the cashew (Anacardiaceae) family, is a small tree cultivated in Iran, Turkey, United States, Syria, Italy, Tunisia, and Greece 1). Iran is one of the biggest producers and exporters of pistachio nuts 2). Fruit of Pistacia vera (pistachio) is used all over the world. Pistachios are globally distributed and consumed as a healthy snack. Pistachios can also be added to many savory dishes such as pastas, marinades and crusts for meat entrees, salsas, and stir-fries as well as a topping for salads, yogurts, and dips. Moreover, different parts of pistachio plant (Pistacia vera L.), including flower, leaf, seed and resins derived from stem, have pharmacological properties like antimicrobial, antioxidant and anti-inflammatory activities 3). Records of the consumption of pistachio as a food date to 7000 BC 4). The tree produces pistachio seeds (nuts) that are widely consumed as food. Pistachio nuts are a rich source of phenolic compounds, known for their high antioxidant activity, and contained not only in the seeds but also in the skin 5). Unfortunately, pistachio nut is also responsible for triggering moderate to severe IgE-mediated reactions in allergic individuals 6). Currently, pistachio nut allergy has gained some special attention, mainly due to its intrinsic relation with cashew nut allergy.

Pistachio is a desert plant that is highly adaptable to abiotic stresses and considered as a tolerant species against drought and salt stresses and is highly tolerant of saline soil. Although pistachio is categorized as a salt-tolerant glycophyte species, its yield is dramatically constrained under the high salinity conditions 7). It has been reported to grow well when irrigated with water having 3,000–4,000 ppm of soluble salts. Pistachio trees are fairly hardy in the right conditions and can survive temperatures ranging between −10 °C (14 °F) in winter and 48 °C (118 °F) in summer. They need a sunny position and well-drained soil. Pistachio trees do poorly in conditions of high humidity and are susceptible to root rot in winter if they get too much water and the soil is not sufficiently free-draining. Long, hot summers are required for proper ripening of the fruit. Pistachio (Pistacia vera L.) often is confused with other species in the genus Pistacia that are also known as pistachio. These other species can be distinguished by their geographic distributions (in the wild) and their seeds which are much smaller and have a soft shell.

To prevent fatty acids in pistachios from oxidation, store pistachios in an airtight container in the refrigerator at 40°F (4°C) for up to 1 year. At room temperature 68°F (20°C), they should be kept in a dry environment and will last several months.

Figure 1. Pistachio

Pistachio

Figure 2. Pistachio nuts

pistachio nuts

Pistachio nutrition

Pistachio nuts are a nutritionally dense food. In a 100 gram serving, pistachio nuts provide 560 calories and are a rich source (20% or more of the Daily Value or DV) of protein, dietary fiber, several dietary minerals (i.e, potassium, phosphorus, magnesium, calcium) and the B vitamins, thiamin and especially vitamin B6 (Pyridoxine) at 131% DV. Pistachio nuts are a good source (10–19% DV) of calcium, riboflavin, vitamin A, vitamin B5, vitamin C, folate, vitamin E (especially γ-tocopherol), and vitamin K. Pistachios are also a good source of vegetable protein (about 21% of total weight), with an essential amino acid ratio higher than most other commonly consumed nuts (ie, almonds, walnuts, pecans, and hazelnuts), and they have a high percentage of branched chain amino acids 8). The amount of total carbohydrates is low to moderate (about 29% by weight), but they are richer in fiber than other nuts with a 10% by weight of insoluble forms and 0.3% of soluble forms (Table 3).

Pistachio nut is high in polyunsaturated fatty acids (PUFAs), monounsaturated fatty acids (MUFAs), flavonoids, and proanthocyanidins 9) and carotenoids (lutein, β-carotene, and γ-tocopherol) content. Saturated fatty acids include palmitic acid (10% of total) and stearic acid (2%). Oleic acid is the most common monounsaturated fatty acid (51% of total fat) and linoleic acid, a polyunsaturated fatty acid, is 31% of total fat. Relative to other tree nuts (see Table 3 below), pistachios have a lower amount of fat and calories but higher amounts of potassium, vitamin K, γ-tocopherol, and certain phytochemicals such as carotenoids and phytosterols. Dry roasted pistachios have a lower fat content (45.82 g/100 g), which is composed mainly of saturated fatty acid (5.6 g), polyunsaturated fatty acid (13.3 g), and monounsaturated fatty acid (24.5 g).

Moreover, pistachios are also a rich source of lutein and zeaxanthin (xanthophyll carotenoids) and phenolic compounds, including anthocyanins, flavonoids, and proanthocyanidins, and their antioxidant capacity is considerable. Pistachios are the nuts that have the highest content of phytosterols, including stigmasterol, campesterol, and β-sitosterol 10). This complete and diverse set of micronutrients and macronutrients means that pistachio nuts are potentially one of the more health-promoting foods. Their beneficial properties, based on pistachios’ specific macronutrient, micronutrient and bioactive molecules will remain unchanged even after cooked. Moreover, other properties such as their contribution to the glycemic index and glycemic load of a particular meal would be improved by their inclusion.

Table 1. Pistachio nuts (raw) nutrition facts

NutrientUnitValue per 100 g
Approximates
Waterg4.37
Energykcal560
EnergykJ2342
Proteing20.16
Total lipid (fat)g45.32
Ashg2.99
Carbohydrate, by differenceg27.17
Fiber, total dietaryg10.6
Sugars, totalg7.66
Sucroseg6.87
Glucose (dextrose)g0.32
Fructoseg0.24
Lactoseg0
Maltoseg0.17
Starchg1.67
Minerals
Calcium, Camg105
Iron, Femg3.92
Magnesium, Mgmg121
Phosphorus, Pmg490
Potassium, Kmg1025
Sodium, Namg1
Zinc, Znmg2.2
Copper, Cumg1.3
Manganese, Mnmg1.2
Selenium, Seµg7
Fluoride, Fµg3.4
Vitamins
Vitamin C, total ascorbic acidmg5.6
Thiaminmg0.87
Riboflavinmg0.16
Niacinmg1.3
Pantothenic acidmg0.52
Vitamin B-6mg1.7
Folate, totalµg51
Folic acidµg0
Folate, foodµg51
Folate, DFEµg51
Vitamin B-12µg0
Vitamin A, RAEµg26
Retinolµg0
Carotene, betaµg305
Carotene, alphaµg10
Cryptoxanthin, betaµg0
Vitamin A, IUIU516
Lutein + zeaxanthinµg2903
Vitamin E (alpha-tocopherol)mg2.86
Tocopherol, betamg0
Tocopherol, gammamg20.41
Tocopherol, deltamg0.8
Vitamin D (D2 + D3)µg0
Vitamin DIU0
Lipids
Fatty acids, total saturatedg5.907
04:00:00g0
6:0g0.012
8:0g0
10:0g0.004
12:0g0
13:0g0
14:0g0.019
15:0g0
16:0g5.265
17:0g0.009
18:0g0.478
20:0g0.046
22:0g0.04
24:0g0
Fatty acids, total monounsaturatedg23.257
14:1g0
16:1 undifferentiatedg0.495
18:1 undifferentiatedg22.674
20:1g0.089
22:1 undifferentiatedg0
24:1 cg0
Fatty acids, total polyunsaturatedg14.38
18:2 undifferentiatedg14.091
18:2 n-6 c,cg14.091
18:3 undifferentiatedg0.289
18:04:00g0
20:2 n-6 c,cg0
20:3 undifferentiatedg0
20:4 undifferentiatedg0
20:5 n-3 (EPA)g0
22:5 n-3 (DPA)g0
22:6 n-3 (DHA)g0
Fatty acids, total transg0
Cholesterolmg0
Phytosterolsmg214
Stigmasterolmg5
Campesterolmg10
Beta-sitosterolmg198
Amino Acids
Tryptophang0.251
Threonineg0.684
Isoleucineg0.917
Leucineg1.604
Lysineg1.138
Methionineg0.36
Cystineg0.292
Phenylalanineg1.092
Tyrosineg0.509
Valineg1.249
Arginineg2.134
Histidineg0.512
Alanineg0.973
Aspartic acidg1.884
Glutamic acidg4.3
Glycineg1.009
Prolineg0.938
Serineg1.283
Other
Alcohol, ethylg0
Caffeinemg0
Theobrominemg0
Anthocyanidins
Cyanidinmg7.3
Petunidinmg0
Delphinidinmg0
Malvidinmg0
Pelargonidinmg0
Peonidinmg0
Flavan-3-ols
(+)-Catechinmg3.6
(-)-Epigallocatechinmg2
(-)-Epicatechinmg0.8
(-)-Epicatechin 3-gallatemg0
(-)-Epigallocatechin 3-gallatemg0.4
(+)-Gallocatechinmg0
Flavanones
Hesperetinmg0
Naringeninmg0
Flavones
Apigeninmg0
Luteolinmg0
Flavonols
Myricetinmg0
Quercetinmg1.5
Isoflavones
Daidzeinmg1.87
Genisteinmg1.75
Glyciteinmg0
Total isoflavonesmg3.63
Formononetinmg0
Coumestrolmg0.01
Proanthocyanidin
Proanthocyanidin dimersmg13.3
Proanthocyanidin trimersmg10.5
Proanthocyanidin 4-6mersmg42.2
Proanthocyanidin 7-10mersmg37.9
Proanthocyanidin polymers (>10mers)mg122.5
[Source: United States Department of Agriculture Agricultural Research Service 11)]

Table 2. Pistachio nuts (dry roasted without added salt) nutrition facts

NutrientUnitValue per 100 g
Approximates
Waterg1.85
Energykcal572
EnergykJ2392
Proteing21.05
Total lipid (fat)g45.82
Ashg3
Carbohydrate, by differenceg28.28
Fiber, total dietaryg10.3
Sugars, totag7.74
Sucroseg7.09
Glucose (dextrose)g0.25
Fructoseg0.22
Lactoseg0
Maltoseg0.13
Galactoseg0.05
Starchg1.38
Minerals
Calcium, Camg107
Iron, Femg4.03
Magnesium, Mgmg109
Phosphorus, Pmg469
Potassium, Kmg1007
Sodium, Namg6
Zinc, Znmg2.34
Copper, Cumg1.293
Manganese, Mnmg1.243
Selenium, Seµg10
Vitamins
Vitamin C, total ascorbic acidmg3
Thiaminmg0.695
Riboflavinmg0.234
Niacinmg1.373
Pantothenic acidmg0.513
Vitamin B-6mg1.122
Folate, totalµg51
Folic acidµg0
Folate, foodµg51
Folate, DFEµg51
Choline, totalmg71.4
Betainemg0.8
Vitamin B-12µg0
Vitamin B-12, addedµg0
Vitamin A, RAEµg13
Retinolµg0
Carotene, betaµg159
Carotene, alphaµg0
Cryptoxanthin, betaµg0
Vitamin A, IUIU266
Lycopeneµg0
Lutein + zeaxanthinµg1160
Vitamin E (alpha-tocopherol)mg2.17
Vitamin E, addedmg0
Tocopherol, betamg0.13
Tocopherol, gammamg23.42
Tocopherol, deltamg0.55
Vitamin D (D2 + D3)µg0
Vitamin DIU0
Vitamin K (phylloquinone)µg13.2
Lipids
Fatty acids, total saturatedg5.645
04:00:00g0
06:00:00g0
8:0g0
10:0g0
12:0g0
13:0g0
14:0g0.012
15:0g0
16:0g4.994
17:0g0.011
18:0g0.558
20:0g0.033
22:0g0.026
24:0g0.011
Fatty acids, total monounsaturatedg24.534
14:1g0.005
15:1g0.009
16:1 undifferentiatedg0.464
17:1g0.02
18:1 undifferentiatedg23.926
18:1 tg0
20:1g0.106
22:1 undifferentiatedg0.005
24:1 cg0
Fatty acids, total polyunsaturatedg13.346
18:2 undifferentiatedg13.125
18:2 n-6 c,cg13.125
18:2 t not further definedg0
18:3 undifferentiatedg0.212
18:3 n-3 c,c,c (ALA)g0.212
18:3 n-6 c,c,cg0
18:04:00g0
20:2 n-6 c,cg0
20:3 undifferentiatedg0.005
20:4 undifferentiatedg0.005
20:5 n-3 (EPA)g0
22:5 n-3 (DPA)g0
22:6 n-3 (DHA)g0
Fatty acids, total transg0
Fatty acids, total trans-monoenoicg0
Cholesterolmg0
Stigmasterolmg2
Campesterolmg10
Beta-sitosterolmg210
Amino Acids
Tryptophang0.262
Threonineg0.714
Isoleucineg0.957
Leucineg1.675
Lysineg1.189
Methionineg0.375
Cystineg0.305
Phenylalanineg1.14
Tyrosineg0.531
Valineg1.305
Arginineg2.228
Histidineg0.535
Alanineg1.016
Aspartic acidg1.968
Glutamic acidg4.49
Glycineg1.054
Prolineg0.98
Serineg1.34
Hydroxyprolineg0.096
Other
Alcohol, ethylg0
Caffeinemg0
Theobrominemg0
[Source: United States Department of Agriculture Agricultural Research Service 12)]

Table 3. Pistachio nuts nutritional value compared with other nuts

Pistachio nuts nutritional value compared with other nuts
[Source: 13)]

Health benefits of pistachio nuts

Pistachio nuts are considered a rich source of many important bio-functional compounds that are useful for the human diet and known for their various pharmacological properties such as antimicrobial, anti-inflammatory, insecticidal, and anti-nociceptive activities 14). Recently, scientists analyzed and described the nutraceutical, antioxidant, and cytoprotective activity of crude phenols and anthocyanins-rich extracts derived from ripe pistachio hulls, a by-product of the pistachio industry 15). As their nutritional profile suggests, pistachios can play an important role in improving such metabolic conditions as overweight, type 2 diabetes mellitus or metabolic syndrome.

Nut consumption is associated with significant reductions in cardiovascular disease risk and all-cause mortality 16). In the Nurses’ Health Study 17), women who consumed >2 servings of nuts per week had an 18% reduction in cardiac death compared with women who did not eat nuts regularly. In short-term, randomized trials, almonds, walnuts and pistachios 18) significantly reduced low-density lipoprotein (LDL) “bad” cholesterol and total cholesterol, when compared with a typical Western diet or diets low in saturated fat 19). Scientists have shown previously that including 1 or 2 servings per day of pistachios in a healthy diet reduced LDL “bad” cholesterol by 9% to 12% 20). The effects of pistachios on the ratio of LDL “bad” cholesterol to high-density lipoprotein “good” (HDL) cholesterol were dose dependent, with larger improvements in LDL “bad” cholesterol/high-density lipoprotein “good” cholesterol 21) and greater reductions in oxidized LDL “bad” cholesterol 22) when participants consumed 2 servings per day. Relative to other nuts, pistachios are a rich source of antioxidants, including lutein, β-carotene, and γ-tocopherol in addition to containing selenium, flavonoids, and proanthocyanidins 23). As would be expected, pistachios have a relatively high in vitro antioxidant capacity 24). Oxidized LDL “bad” cholesterol 25) and lipid peroxidation products are found in elevated concentrations in atherosclerotic plaques 26) and are thought to play an important role in the development and progression of atherosclerosis 27). Thus, strategies that reduce in body oxidative stress are thought to confer cardioprotective effects.

Lipid Profile

Previous dietary interventions with pistachios conducted in humans have shown improvements in lipoprotein profiles 28) and one reported a beneficial effect on serum antioxidant status (measured using a malondialdehyde assay) in 44 males and females who consumed a diet that provided 20% of their energy as pistachios for 3 weeks 29). Another study 30) demonstrated beneficial effects of pistachios on multiple biomarkers of oxidative state. The study found significant decreases in serum oxidized-LDL “bad” cholesterol in participants following the pistachio-enriched diets relative to the control diet 31). The decrease in oxidized-LDL “bad” cholesterol was accompanied by a significant increase in serum concentrations of antioxidants (relative to the control diet), including γ-tocopherol, lutein and β-carotene, thus indicating a beneficial effect of pistachios on concentrations of serum antioxidants 32). The results of this 2016 systematic review 33) provide solid evidence that intake of pistachio nuts may exerts favorable effects on the traditional blood profile, provided that their consumption does not increase the habitual or recommended daily caloric intake.

In summary, evidence suggests that pistachios may improve well-established and novel blood lipid markers of atherosclerosis and therefore help decrease cardiovascular risk. In order to fully establish the potential health effects of pistachio consumption on the prevention of cardiovascular events clinical trials needed to be carried out in the future.

Figure 3. Possible health benefits of pistachios consumption

health benefits of pistachio nuts

Note: CVD = cardiovascular disease

[Source 34)]

Lowers Blood Pressure

Several prospective studies have shown an inverse association between nut consumption and blood pressure or hypertension 35). However, the results of clinical trials are more controversial. The intake of 10% of energy in the form of pistachios for 1 month significantly reduced systolic blood pressure and made no difference in diastolic blood pressure compared with the control nut-free group 36). Similarly, a recent study conducted in type 2 diabetes mellitus subjects showed a reduction in systolic blood pressure after 4 weeks consuming a diet with 20% energy from pistachios 37). Moreover, a recent systematic review and meta-analysis of more than 20 randomized controlled trials found that although diastolic blood pressure was reduced by the intake of mixed nuts, pistachios alone seemed to have the strongest effect on reducing both systolic blood pressure and diastolic blood pressure 38).

Walnut, hazelnut, and pistachio consumption also improves the circulating concentrations of endothelial markers and endothelial function 39).

In conclusion, chronic pistachio consumption has proved to have a beneficial effect on blood pressure and endothelial function, which may help to improve cardiovascular risk 40).

Glucose and Insulin Metabolism

Pistachios have more total carbohydrates (29% w/w) than do other nuts, but their consumption has no deleterious effect in subjects with abnormal glucose and insulin metabolism.

Data from several epidemiological studies and clinical trials suggest that the frequency of nut consumption is inversely related to an increased risk of type 2 diabetes mellitus. This may be because of the fact that nuts are relatively high in fiber, healthy fats, antioxidants, and anti-inflammatory content 41). In addition, among all nuts, pistachios have a low glycemic index (GI), suggesting that they may reduce postprandial glycemia and insulinemia and therefore contribute to reducing the type 2 diabetes mellitus risk 42). Pistachios consumed alone had a minimal effect on postprandial glycemia, but the addition of pistachios to a meal containing foods rich in carbohydrates with a high glycemic index (eg, pasta, parboiled rice, or instant mashed potatoes) 43) or bread 44) reduces postprandial glycemia in a dose-dependent response.

Several clinical studies have investigated the effect of pistachio consumption on glucose concentrations. They observed a significant decrease in fasting plasma glucose 45), in glucose but not in insulin blood levels 46), and in both fasting plasma glucose and insulin levels 47) after pistachio intake. Only 1 cross-over study conducted on metabolic syndrome subjects free of type 2 diabetes has shown no significant changes in fasting plasma glucose or in insulin concentrations during the pistachio-enriched diet period compared with the intervention period without pistachios 48).

Pistachio consumption has also proved to have beneficial effects on diabetes control. In a randomized controlled study 49), the intake of mixed nuts (including pistachios) for 3 months in type 2 diabetes mellitus subjects, as a replacement for carbohydrate-containing foods, demonstrated for the first time a significant decrease in hemoglobin A1c in a full-nut dose compared with a half-nut and control-muffin doses. Results were similar in a recent crossover trial with 48 diabetic participants after 3 months of pistachio consumption 50). Pistachio intake has also recently been found to significantly enhance the glucose and insulin metabolism of prediabetic patients 51) and improve insulin resistance status and other cardiovascular risk factors.

Despite the positive results observed for glucose metabolism, more studies need to be made to evaluate the long-term effects of pistachio consumption on insulin resistance and type 2 diabetes mellitus prevention and control.

Satiety Regulation and Weight Management

Because nuts are energy-dense foods with a high fat content, one of the main concerns regarding the regular consumption of nuts in a worldwide pandemic of overweight and obesity is that nuts are believed to be fattening. To date, however, epidemiological studies have failed to find any association between nut or pistachio consumption and either weight gain or an increased risk of obesity 52). Likewise, controlled feeding trials confirm that adding nuts to usual diets does not induce weight gain 53). Several studies that have evaluated pistachios’ effect on body weight as a secondary outcome have reiterated their null effect on body weight and body mass index 54). Only one recent study conducted in type 2 diabetes mellitus subjects has found a significant reduction of body mass index after pistachio consumption 55).

These findings may be explained by the energy density of pistachios; their content in fiber, protein, and unsaturated fatty acids; and their crunchy physical structure, which may induce satiety and therefore reduce subsequent food intake 56). It has been speculated that various signaling systems (ie, mechanical, nutrient, and sensory) are activated by mastication, which may modify appetitive sensations 57). To date, only 2 studies have evaluated the satiating properties of pistachio nuts in humans. The conclusions are that the consumption of in-shell pistachios led to lower calorie intake than the consumption of kernels 58) and that the visual cue of empty pistachio shells helped the participants to consume fewer calories during the day 59).

In addition, the monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) that nuts contain have a greater thermic effect that will induce higher thermogenic effect 60) than saturated fatty acids, which can lead to less fat accumulation by an increase in sympathetic activity in brown adipose tissue 61). Finally, after nut intake, fat is malabsorbed to a slight extent largely because the fat in the walls of nut cells is not completely digested in the gut 62), suggesting that energy from nuts is poorly absorbed. Therefore, the metabolized energy contained in these types of nut is less than predicted by the Atwater general factors, which is the system used for the calculation of the available energy of foods developed from experimental studies in the early years of the 20th century 63).

Traditional medicine uses

In traditional Iranian medicine, different parts of pistachio have been used for a long time as useful remedies for different diseases, for example, the fruit kernel of pistachio as a cardiac, stomach, hepatic, and brain tonic 64).

Table 4. Traditional medical uses of pistachio (Pistacia vera L.)

Pistacia vera IranNut shellTonic, sedative, and antidiarrhea65)
FruitFood66)
JordanOilFacial skin cleanser67)
TurkeyResinAsthma, stomach ache, and hemorrhoids68)
[Source 69)]

New trends in pistachio research

Pistachio in the prevention of type 2 diabetes mellitus and other Metabolic Diseases

Research has focused widely on the beneficial effects of pistachios on such conditions as type 2 diabetes mellitus and metabolic syndrome 70). However, very little information is currently available on the potential role pistachio nuts play in preventing the development of chronic diseases such as type 2 diabetes mellitus.

Pistachios in cancer or neurodegenerative diseases

Vitamin E and other antioxidants provide some protection against certain forms of cancer. Therefore, foods such as pistachios, with a high content of γ-tocopherol (a form of vitamin E) and other antioxidants may reduce the risk of different types of cancer 71). Moreover, the skin of nuts contains considerable amounts of resveratrol 72), which has been widely studied for its role in cancer, but new research is now changing this focus to other diseases such as Alzheimer’s or Parkinson’s disease 73).

Pistachio and gut microbiota

Recent findings have shown that both pistachios and almonds have a potential prebiotic effect in healthy populations, and that the effect of the former is greater 74). Thereby, pistachios’ microbiota modulation increased the number of butyrate-producing bacteria, identified as potentially beneficial, whereas bifidobacteria was not affected. However, new investigations should be performed to contrast and further explore these findings. Regulation of the phyla composition or the production of regulatory and protective molecules (eg, butyrate) by our gut microbiota could be mediators of the well-established beneficial properties of pistachios and other nuts.

References   [ + ]