Hazelnut

Studies in people

• Open question

  Cholesterol and heart health⁴

  Eating hazelnuts may slightly improve cholesterol, but studies are too mixed for scientists to know for sure.

• Open question

  Treating food allergy⁶

  Hazelnut oral immunotherapy helped some children with hazelnut allergy, but many stopped treatment and some had serious reactions.

• Benefit

  Nut allergy treatment⁸

  In people with hazelnut allergy, hazelnut treatment desensitized 29 of 30, but cross-desensitization to walnut and cashew was unlikely.

• Open question

  Liver cancer risk⁹

  Hazelnut paste can contain aflatoxins, but levels found in Turkey were not a health concern for adults.

• Benefit

  Heart and blood vessel health¹⁰

  Eating hazelnut with a fast-food meal lowered a blood marker linked to heart vessel problems in people.

• Open question

  Daily allergy therapy burden¹⁶

  In children with hazelnut allergy, daily hazelnut treatment helped many, but some stopped because they grew to hate eating it.

• Benefit

  Weight and antioxidant genes¹⁹

  People who ate hazelnuts daily for six weeks gained no weight, and their antioxidant genes became more active.

Animal and lab studies only

• Open question

  Gut health²³

  In lab and animal studies, hazelnut skin may feed gut bacteria, but scientists do not yet know whether this happens in people.

Study type not stated

• Open question

  Nutrient levels in nuts²¹

  How hazelnuts are grown, roasted and skinned changes their nutrients, and the skin holds many antioxidants.

• Benefit

  Nut byproducts and health²²

  Hazelnut kernels and their skins and shells hold plant compounds that may have helpful effects on health.

Found in some samples or products

These come from where it was grown, how it was processed or cooked, or what it was made into. They are not about the ingredient itself, so the signal does not count them.

• Toxins found in nuts²⁰

  Many kinds of mould toxins have been found in hazelnut samples, not just the ones tests usually look for.

Allergies and intolerances

These are about people with an allergy, an intolerance or coeliac disease. The signal is about the ingredient itself, and these are about the person eating it, so the signal does not count them.

• Tree nut allergy³

  Hazelnut is a common tree nut that can cause allergic reactions, from mild to severe, in people who are sensitive to it.

• Nut allergy risk⁵

  Hazelnut allergy often lasts a lifetime and can cause severe reactions, so scientists are testing treatments to build tolerance.

• Low-dose food challenge⁷

  In children with hazelnut allergy, small doses of hazelnut caused mostly mild mouth itching, and most reached the full amount.

• Nut allergy risk¹²

  People allergic to hazelnut can react badly, and food processing lowers but does not remove hazelnut allergens.

• Nut allergy severity¹³

  Some people react to hazelnut with mild mouth itching, others with serious allergic symptoms.

• Nut allergy patterns by age¹⁵

  In people with hazelnut antibodies, the hazelnut proteins that reacted varied by age and region.

• Blood markers predicting challenge reactions¹⁸

  In children tested for hazelnut allergy, higher levels of certain blood markers made a reaction to a hazelnut challenge more likely.

How it’s made and used

• False positive blood tests¹¹

  Blood tests for hazelnut allergy often say yes when a child is not truly allergic.

• Allergy test accuracy¹⁴

  In Japanese children, high levels of one hazelnut protein and low levels of another helped tell who was truly allergic to hazelnut.

• How spreads feel in the mouth¹⁷

  How creamy or oily a hazelnut spread feels depends on its thickness and tiny bits, not just its taste.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.