Pistachios

Green kernels of the pistachio tree from western Asia, California and Sicily. Snack on them, chop them over salads and desserts or make pesto. Go for unsalted.

What are pistachios? The desert nut of kings

Pistachios (Pistacia vera) don't grow on leafy shrubs like European hazelnuts. They grow on extremely hardy, ancient desert trees in the hot summers of Iran, Syria, California and Sicily (Bronte pistachios). In Mesopotamia they were so precious that, according to legend, they were grown exclusively in the Hanging Gardens for the Queen of Sheba. On the tree, the hard beige shell splits open by itself in the strong sun, revealing the soft, deep purple-green kernel inside. Nutritionally, pistachios are one of the most underrated tree nuts, because their profile differs from walnuts or cashews in a few unusual ways.

The macros: less fat, all the essential amino acids

Nuts are usually thought of as pure "fat bombs" (mostly over 65g fat per 100g) and incomplete protein sources. Pistachios break that rule in a surprising way:

• Calories: at about 560 kcal per 100g, they have noticeably less fat and fewer calories than most nuts on the snack shelf.
• A complete protein: a scientific analysis from 2020 rated roasted pistachios as a "complete protein". That means they contain all 9 essential amino acids in sufficient amounts – a status that, in the plant world, is otherwise mostly reserved for quinoa and soya.
• Visible pigments (lutein): unlike almost all other nuts, pistachios are green and purple. These colours come from plant pigments, including lutein and zeaxanthin.

What researchers have measured

Melatonin in pistachios

Lab analyses from 2014 found melatonin in pistachios from Iran and California – not just traces, but more than in most other foods measured so far. Melatonin is a substance your body also makes itself. Whether a handful of pistachios has any noticeable effect on you hasn't been shown.

Pistachios with carb-rich food

Researchers call it the "pistachio effect": in studies, people ate pistachios together with high-GI foods such as white bread or pasta, and their blood glucose was measured afterwards. The idea is that the fibre and fat in pistachios slow down how quickly the carbs from the rest of the meal are absorbed.

Important: avoid the supermarket trap

Standard snack bags from the discount shop are a different story: these pistachios are often roasted hard in low-quality oil and so thickly coated in salt, shell and all, that they become a very salty snack. Look for raw, in the shell, completely unsalted, organic if you like. Shelling them slowly by hand also slows you down – a small mindful-eating trick.