Hazelnuts are nutrient-dense nuts with heart-healthy fats, fiber, and antioxidants

Hazelnuts contain mostly monounsaturated fat—the same type found in olive oil—along with polyunsaturated fat. A one-ounce serving (about 21 nuts) has roughly 17 grams of fat, 4 grams of fiber, and 4 grams of protein. They also deliver vitamin E, magnesium, copper, and manganese, plus compounds called polyphenols that act as antioxidants in your body.

Unlike some nuts, hazelnuts are relatively low in omega-6 polyunsaturated fat, which matters because most people already consume plenty of omega-6 from other foods. This balance is one reason researchers have studied hazelnuts specifically in heart health research.

Key Takeaways

  • Hazelnuts are high in monounsaturated fat, the type linked to heart health, and contain 4 grams of fiber per ounce.
  • They provide vitamin E and polyphenol antioxidants, which may help reduce inflammation in your body.
  • One ounce of hazelnuts contains about 180 calories, so portion control matters if you are watching your calorie intake.
  • Hazelnuts work raw, roasted, or as hazelnut butter, though roasting may increase some antioxidant activity.

How hazelnuts affect cholesterol and blood vessel health

Several studies have looked at whether eating hazelnuts changes cholesterol levels. Research published in nutrition journals found that people who ate hazelnuts regularly showed modest improvements in LDL cholesterol (the type associated with plaque buildup) and triglycerides, while HDL cholesterol (the protective type) stayed stable or improved slightly.

The monounsaturated fat in hazelnuts appears to be the main driver of these changes. Monounsaturated fats can help reduce LDL without lowering HDL, which is the pattern doctors prefer to see. However, these improvements were usually small—not a replacement for medication if your doctor has prescribed it, but a useful addition to a diet that already includes other heart-healthy foods.

Hazelnuts also contain arginine, an amino acid your body uses to make nitric oxide, a compound that helps blood vessels relax and improves blood flow. This is one reason nuts in general appear in heart health guidelines from organizations like the American Heart Association.

Antioxidants and inflammation

Hazelnuts contain polyphenols, a broad category of plant compounds that neutralize free radicals—unstable molecules that can damage cells. Roasted hazelnuts often have higher polyphenol levels than raw ones, because heat can break down cell walls and make these compounds more available to your body.

Chronic inflammation is linked to heart disease, type 2 diabetes, and some cancers. While no single food cures inflammation, eating nuts regularly as part of a varied diet may help reduce inflammatory markers in your blood. Studies measuring C-reactive protein (a marker of inflammation) have shown modest decreases in people who eat tree nuts regularly, though the effect is usually small.

Vitamin E in hazelnuts also acts as an antioxidant, protecting cell membranes from damage. One ounce of hazelnuts provides about 20% of the daily recommended amount of vitamin E.

Hazelnuts and blood sugar control

Hazelnuts have a low glycemic index, meaning they do not cause a rapid spike in blood sugar. The combination of fat, protein, and fiber slows digestion and keeps glucose rising gradually. This matters for people managing type 2 diabetes or trying to avoid blood sugar crashes that lead to hunger and fatigue.

The fiber in hazelnuts—about 4 grams per ounce—also feeds beneficial bacteria in your gut, which may improve insulin sensitivity over time. However, hazelnuts are calorie-dense, so portion size still matters if weight management is part of your blood sugar strategy.

How to include hazelnuts in your diet

Hazelnuts work in several forms: whole raw nuts, roasted and salted, unsalted roasted, or as hazelnut butter. Raw hazelnuts have a slightly bitter skin; roasting removes some of that bitterness and may increase antioxidant availability. Hazelnut butter offers the same nutrients as whole nuts but is easier to measure and blend into smoothies or oatmeal.

A standard serving is one ounce, roughly a small handful or about 21 whole nuts. This provides the nutrients mentioned above without excess calories. You can also use hazelnuts in smaller amounts—crushed on yogurt, mixed into salads, or added to baked goods—to get their benefits without committing to a full ounce at once.

If you are new to hazelnuts, start with a small amount to check for any digestive changes; the fiber and fat can cause bloating or loose stools if you eat too much too quickly. People with tree nut allergies should avoid them entirely.

Hazelnuts compared to other tree nuts

Hazelnuts are similar to almonds and macadamia nuts in fat profile but differ in specific nutrients. Almonds have more protein and calcium; macadamia nuts have even higher monounsaturated fat but less fiber. Walnuts stand apart because they are high in omega-3 polyunsaturated fat, which hazelnuts are not.

The "best" nut depends on what you are trying to achieve. For heart health and antioxidants, hazelnuts are a solid choice. For omega-3s, walnuts are better. For protein, almonds win. Eating a variety of nuts gives you the broadest range of nutrients, since each type brings something different to the table.

Storage and shelf life

Hazelnuts keep longest in a cool, dry place in an airtight container. Whole nuts in the shell stay fresh for several months at room temperature; shelled nuts last about a month. In the refrigerator, shelled hazelnuts last two to three months; in the freezer, up to a year.

Hazelnut butter should be stored in a cool cupboard or refrigerator depending on whether it contains added oils. Check the label—some brands separate and need stirring, while others stay blended. Once opened, use within a few weeks to avoid rancidity, which occurs when the oils oxidize.

Frequently Asked Questions

Do hazelnuts have as much protein as almonds?

No. One ounce of hazelnuts has about 4 grams of protein, while almonds have about 6 grams per ounce. If protein is your main goal, almonds or peanuts are better choices. Hazelnuts are stronger for fat quality and antioxidants.

Can I eat hazelnuts if I have a tree nut allergy?

No. Hazelnuts are tree nuts, so anyone with a tree nut allergy should avoid them. Allergies to different tree nuts do not always overlap, but a doctor or allergist should confirm it is safe before you try hazelnuts if you have any tree nut allergy.

Is hazelnut butter as healthy as whole hazelnuts?

Yes, nutritionally they are equivalent—the same fats, fiber, and vitamins per ounce. The difference is convenience and how quickly you eat them. Whole nuts take longer to chew, which may help you feel full faster. Butter is easier to measure and mix into foods but easier to overeat.

Do roasted hazelnuts lose nutrients?

Roasting does not destroy the main nutrients—fat, fiber, protein, and minerals remain stable. Some heat-sensitive vitamins like vitamin C may decrease slightly, but hazelnuts are not a major source of vitamin C anyway. Roasting may actually increase polyphenol antioxidants by making them more available to your body.

How many hazelnuts should I eat per day?

One ounce (about 21 nuts) per day is a standard serving that fits into most diets without excess calories. Some people eat more as part of a balanced diet, but portion control matters because hazelnuts are calorie-dense at about 180 calories per ounce.