Tasty and nutritious, pistachios are eaten as a snack and used as an ingredient in many dishes.

Their green color makes them popular in ice creams, confections, baked goods, sweets, butter, oil, and sausages, as they add a distinct and natural color and flavor.

However, if you have a nut allergy or are simply unsure, you may have wondered what exactly pistachios are and whether they belong to the nut family.

This article explains whether pistachios are nuts and reviews some of the health benefits of eating pistachios.

When most people think of nuts, they think of small hard kernels like almonds, walnuts, cashews, and peanuts.

Yet, not all foods that people commonly think of as nuts are botanically classed as such.

Several parts of plants are often grouped together under the term “nuts” (1):

  • True botanical nuts. These are fruits with a hard inedible shell and seed. The shell does not open to release the seed by itself. True nuts include chestnuts, hazelnuts, and acorns.
  • Seeds of drupes. Drupes are fleshy fruits that surround a stone or pit that contains a seed. Some drupe seeds that are commonly called nuts include almonds, cashews, pecans, walnuts, and coconut.
  • Other seeds. These include seeds without an enclosure, such as pine nuts and gingko nuts, as well as seeds enclosed within a fruit, such as macadamias and peanuts.

While these are all quite different from a botanical perspective, in culinary terms and in general, they’re all referred to as nuts.

Tree nuts are a common allergen and include both true nuts and seeds that come from a tree (2).

summary

True botanical nuts are fruits with a hard inedible shell and seed, such as chestnuts and hazelnuts. Still, common and culinary usage also includes a variety of seeds, such as almonds, cashews, pine nuts, macadamias, and peanuts.

Pistachio may refer to any one of several tree species of the Pistacia genus, which is part of the same family as cashews, mango, and poison ivy (3).

Still, Pistacia vera is the only tree that produces edible fruits, which are commonly known as pistachios.

The pistachio is native to Western Asia and the Middle East, and evidence indicates that fruits of the tree have been eaten for over 8,000 years (3, 4).

Today, the largest producers of pistachios are Iran, the United States, and Mediterranean countries (5).

Pistachio trees grow in dry climates and can reach up to 39 feet (12 meters) in height (4).

In the spring, the trees develop grape-like clusters of green colored fruits, known as drupes, which gradually harden and turn red.

Within the fruit is a green and purple seed, which is the edible part of the fruit.

As the fruits ripen, the shell hardens and splits open with a pop, exposing the seed within. The fruits are picked, hulled, dried, and often roasted before being sold.

Because pistachios are the seed of a drupe, they are not a true botanical nut. However, in the culinary world, pistachios are treated as nuts, and they’re also classified as a tree nut allergen (4, 6).

Summary

Pistachios are the seeds of the fruits of the Pistachio vera tree, which produces clusters of small fruits that gradually harden and split, exposing the seed within. Though they’re seeds, they’re considered nuts in culinary settings and classified as a tree nut allergen.

Pistachios are very nutritious and energy dense. About 3.5 ounces (100 grams) of raw pistachio nuts provide (7):

  • Calories: 569
  • Protein: 21 grams
  • Carbs: 28 grams
  • Fat: 46 grams
  • Dietary fiber: 10.3 grams
  • Copper: 144% of the Daily Value (DV)
  • Vitamin B6: 66% of the DV
  • Thiamine: 58% of the DV
  • Phosphorus: 38% of the DV
  • Magnesium: 26% of the DV
  • Iron: 22% of the DV
  • Potassium: 21% of the DV
  • Zinc: 21% of the DV

Additionally, pistachios contain significant amounts of sodium, selenium, riboflavin, vitamin E, choline, folate, vitamin K, niacin, and calcium (7).

Eating pistachio nuts has been linked to improved heart health due to its high levels of healthy fats, fiber, and antioxidants, such as carotenoids, phytosterols, flavonoids, and resveratrol (4, 8, 9).

In one 4-week study in 15 people with moderately high cholesterol, eating 15% of daily calories from pistachios reduced total and LDL (bad) cholesterol and increased HDL (good) cholesterol levels (10).

In a comparable 4-week study in 22 young men, eating 20% of their daily calories from pistachios improved blood vessel dilation and decreased cholesterol and blood sugar levels (11).

Interestingly, despite their high calorie content, eating pistachios is not linked to significant weight gain. It appears that when adding pistachios to their diet, people are less hungry and naturally decrease their intake of other calories (4, 8, 12, 13).

Therefore, adding pistachios to your diet could be a great way to boost your nutrient intake and promote heart health without adding to your waistline.

Summary

Pistachios are energy dense and very rich in protein, healthy fats, dietary fiber, vitamins, and minerals. Additionally, they may promote heart health by reducing LDL (bad) cholesterol and boosting HDL (good) cholesterol.

Pistachios are not true botanical nuts. In fact, they’re the edible seed of the pistachio tree fruit.

However, like many other seeds, they’re still considered a nut for culinary purposes, as well as a tree nut among those with allergies.

If a tree nut allergy isn’t a concern of yours, pistachios make a great addition to your diet, as they’re highly nutritious and promote heart health.