Hazelnuts

Hazelnuts grow on a large shrub or small tree that flowers very early in spring, before it has leaves. The pale yellow male catkins release pollen on the wind. The female flowers are so small that only their bright red styles show. The nuts fall from their husks 7 to 8 months after pollination.

The species name, Corylus avellana, points to Avella, a town in Italy, and goes back to Pliny the Elder’s first-century Natural History.

Raw hazelnuts get 84% of their calories from fat, and most of it is monounsaturated. They have 45.7 g per 100 g, second among the 123 foods on this site.

One ounce (28 g) has 178 calories. It gives 28% of the Daily Value (the daily target on US food labels) for vitamin E, 76% for manganese and 54% for copper. For biotin, per 100 g only 1 of 75 foods here has more.

The names overlap. The USDA database lists one entry called hazelnuts or filberts, and the nutrition numbers on this page come from it. Most trials below used plain hazelnuts, but a few used oil, bread or a chocolate spread, and the cards say so.

Health benefits of hazelnuts

• ★★★Lower “bad” LDL cholesterolAcross 61 trials, one daily ounce of tree nuts lowered it (by 4.8 mg/dL), but this is for nuts as a group. In three pooled hazelnut trials, it fell a little (0.15 mmol/L), which only just reached statistical significance.
• ★★No change in body weightIn 118 people, about 1100 kJ a day of hazelnuts did not change body composition over 12 weeks, compared with chocolate, crisps or no snack.
• ★★No change in inflammation markersIn 107 healthy overweight or obese people, 30 g or 60 g of hazelnuts a day for 12 weeks did not change inflammation markers.
• ★★Raw and roasted hazelnuts gave similar LDL resultsIn 72 people eating 30 g a day for 28 days each, total and LDL cholesterol did not differ between raw and dry-roasted hazelnuts.
• ★Better blood vessel function in one small studyIn 21 people with high cholesterol, a hazelnut-rich diet for 4 weeks improved how much an artery widens (flow-mediated dilation) by 56.6%. There was no separate control group.

Who should be careful with hazelnuts

Most people can eat hazelnuts freely. Take a little care if one of these applies:

• Hazelnut allergy. Hazelnut is the main cause of nut allergy in Europe. Its storage proteins Cor a 9 and Cor a 14 are linked to severe reactions. So anyone with a diagnosed allergy should avoid hazelnuts and ask an allergist before trying any form.
• Birch pollen allergy. The hazelnut protein Cor a 1 resembles Bet v 1, a birch pollen protein, and usually causes only an itchy mouth. Roasting lowers the effect. But 5 of 17 birch pollen allergic patients with raw hazelnut allergy still reacted to roasted nuts, mildly.
• Young children. The CDC lists whole or chopped nuts, and chunks or spoonfuls of nut butter, as choking hazards for young children.

How to choose, store and eat hazelnuts

• Raw or roasted: in 72 people, 30 g a day of raw or dry-roasted, lightly salted hazelnuts did not differ for total or LDL cholesterol.
• Whole, sliced or ground: in 48 people, 30 g a day of any of the three forms improved cholesterol about equally.
• Chocolate hazelnut spread: one popular brand lists 21 g of sugar, 19 g of it added, in a 2-tablespoon (37 g) serving. So treat it as a sweet spread rather than a nut serving.

Look for kernels that are round, cream-colored inside, smooth and crisp, without shriveling or spots. Hazelnuts store better in the shell than shelled, and cold storage keeps them longest. Well-sealed roasted ones can keep six months to a year or longer in the freezer.

Their oils can turn rancid with time, so taste a nut before you use a batch. One ounce is 178 calories, and the FDA claim above uses 1.5 oz a day.

History of hazelnuts

People ate hazelnuts long before farming. In 1995, archaeologists found a Mesolithic (Middle Stone Age) midden, a rubbish pit, on the Scottish island of Colonsay. It held hundreds of thousands of burned hazelnut shells, dated to about 8,000 years ago.

Hazelnuts also gave their tree its Latin name. Linnaeus took avellana from the botanist Leonhart Fuchs. Fuchs called the plant Avellana nux sylvestris, the wild nut of Avella, a name he drew from Pliny the Elder.

Today Turkey dominates the crop. It grew about 650,000 tonnes in 2023, 57.7% of the world total of 1,125,221 tonnes, according to FAO (UN food agency) figures.

A 2020 genome study of Turkish hazelnut found no sign of an extreme bottleneck during domestication. It suggested that hazelnut may have been domesticated more than once. Hazelnut is important to rural communities on Turkey’s northern coast, where a new disease outbreak has cut yields.

Hazelnuts also changed chocolate. Gianduja, chocolate blended with hazelnut paste, was invented in Turin during Napoleon’s regency (1796 to 1814). It takes its name from Gianduja, a carnival marionette who stands for the typical Piedmontese. In 1852 the Turin firm Caffarel invented the gianduiotto, a small ingot-shaped piece of it.

The best-known hazelnut spread came after World War II. In 1946 Pietro Ferrero, who ran a bakery in Alba, Italy, sold a first 300 kg batch of a gianduja-based paste, Pasta Giandujot. In 1963 Michele Ferrero and Francesco Rivella reworked the recipe and renamed it Nutella. The first jar left the Alba factory on 20 April 1964.

It was developed in Piedmont when postwar rationing had cut the supply of cocoa. A 2014 report put Ferrero’s use at 25 percent of the global hazelnut supply.

In the United States, the crop is centered almost entirely in Oregon’s Willamette Valley, which grows about 99 percent of the national total. Oregon State University says George Dorris planted the state’s first commercial orchard about a century before 2005. It covered five acres between the McKenzie and Willamette rivers. Eastern filbert blight, a fungus from the eastern United States, had reached the northern end of the valley by 1986.

Frequently asked questions about hazelnuts

Are hazelnuts good for you?

For most people, yes. One ounce (28 g) of raw hazelnuts has 178 calories, 4.2 g of protein and 2.7 g of fiber. It also gives 28% of the Daily Value for vitamin E.

Three randomized trials pooled to a 0.15 mmol/L drop in LDL cholesterol. In a trial, 118 people eating daily hazelnuts for 12 weeks did not gain weight compared with no snack. That evidence is moderate, and hazelnut allergy is the main exception.

How many hazelnuts should you eat a day?

No study sets an ideal amount. Trials used 30 g, 40 g and about 57 g a day, and the FDA claim for most nuts uses 1.5 oz. In 107 overweight adults, liking for nuts held steady at 30 g a day but fell at 60 g. At 178 calories an ounce, the amount that suits you depends on what else you eat.

Do hazelnuts lower cholesterol?

A little. Pooled randomized trials of hazelnuts lowered LDL by 0.15 mmol/L. A meta-analysis of 61 tree nut trials found 4.8 mg/dL per daily ounce.

In children with high cholesterol, though, hazelnuts did not lower LDL clearly more than diet advice alone. In people with type 2 diabetes, they changed neither LDL nor fasting blood sugar.

Are hazelnuts and filberts the same thing?

Largely, in everyday use. The USDA lists them in one entry, hazelnuts or filberts, and the numbers on this page come from it. Reference works note that the names cobnut and filbert are applied depending on the species. So the words can mean slightly different nuts in some places.

Are hazelnuts good for people with diabetes?

The evidence is thin. In an 8-week trial in 50 people with type 2 diabetes, hazelnuts replacing 10% of calories did not change fasting blood sugar. In a smaller trial, bread with 30 g of hazelnuts lowered the blood sugar rise after eating compared with plain bread.

Raw hazelnuts have 2 g of net carbs per ounce, but check portions with your care team.

Is hazelnut spread healthy?

Not in the way plain hazelnuts are. One popular brand lists 200 calories and 21 g of sugar in a 2-tablespoon (37 g) serving, 19 g of it added.

A trial in 20 smokers found a 60 g portion of hazelnut and cocoa spread raised blood vessel dilation within two hours. But it measured only that window and cannot be credited to the hazelnuts alone.

Are hazelnuts high in protein?

They have a moderate amount. Raw hazelnuts have 15 g of protein per 100 g, or 4.2 g in an ounce, which is 9% of their calories. Lysine is the limiting amino acid, so they are better as part of a mixed diet than as a main protein source.

Is it safe to eat hazelnuts raw?

For most people, yes. Raw hazelnuts did as well as dry-roasted ones for total and LDL cholesterol in a 72-person trial. People with birch pollen allergy often get an itchy mouth from raw hazelnuts. Roasting lowers that effect but not for everyone: 5 of 17 such patients still reacted to roasted nuts.