# Hazelnut (Corylus avellana)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/hazelnut
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-04-03
**Evidence Score:** 2 / 10
**Category:** Nut
**Also Known As:** Corylus avellana, European hazelnut, common hazel, cobnut, filbert, Barcelona nut, avellana, nocciola, noisette

## Overview

Hazelnut (Corylus avellana) is rich in oleic acid, tocopherols, and polyphenols including taxifolin and quercetin, which drive its antioxidant and [anti-inflammatory](/ingredients/condition/inflammation) activity. These compounds inhibit COX-2 enzymes and scavenge [free radical](/ingredients/condition/antioxidant)s via DPPH and ABTS pathways, supporting [cardiovascular](/ingredients/condition/heart-health) and metabolic health.

## Health Benefits

• [Anti-inflammatory](/ingredients/condition/inflammation) effects through COX-2 inhibition (36-64% reduction) - preliminary evidence from in vitro studies only
• [Antimicrobial](/ingredients/condition/immune-support) activity against Gram-positive bacteria (MIC 0.1 mg/mL) and Candida albicans - in vitro evidence only
• [Antioxidant](/ingredients/condition/antioxidant) properties via DPPH/ABTS radical scavenging (IC50 11-13 μmol/L) - preliminary in vitro data
• Rich source of heart-healthy oleic acid (71-85% of total fats) - compositional analysis only
• Contains tocopherols and phenolic compounds - no clinical evidence for health effects

## Mechanism of Action

Hazelnut polyphenols, particularly taxifolin, quercetin, and kaempferol, inhibit cyclooxygenase-2 (COX-2) enzyme activity, reducing [prostaglandin](/ingredients/condition/inflammation) E2 synthesis and downstream inflammatory signaling by 36–64% in vitro. Alpha-tocopherol and beta-sitosterol neutralize [reactive oxygen species](/ingredients/condition/antioxidant) by donating hydrogen atoms to DPPH and ABTS radicals, interrupting lipid peroxidation chain reactions. Oleic acid (comprising up to 83% of hazelnut fatty acids) activates PPAR-alpha receptors, modulating lipid [metabolism](/ingredients/condition/weight-management) and suppressing NF-kB-mediated inflammatory gene expression.

## Clinical Summary

Most evidence for hazelnut's bioactive effects derives from in vitro cell culture and animal studies, with limited randomized controlled trials in humans. A small number of human trials (n=20–48 participants) incorporating hazelnuts into diets for 4–8 weeks have demonstrated modest reductions in LDL cholesterol (5–10%) and improvements in plasma tocopherol levels. One crossover study in hypercholesterolemic adults found that replacing dietary fat with hazelnut fat improved [endothelial function](/ingredients/condition/heart-health) markers, though sample sizes were insufficient to draw definitive conclusions. Overall, the evidence is promising but preliminary, requiring larger, well-controlled trials to confirm efficacy for specific health outcomes.

## Nutritional Profile

Per 100g raw hazelnuts: Energy ~628 kcal, Total fat ~60.8g (predominantly monounsaturated oleic acid 71-85% of total fatty acids, ~45-51g; linoleic acid/omega-6 ~7-8g; palmitic acid ~5-6g; stearic acid ~2-3g), Protein ~15g (rich in arginine, glutamic acid, leucine; limiting amino acid is lysine), Total carbohydrates ~16.7g (digestible ~10g, dietary fiber ~9.7g including both soluble and insoluble fractions). Micronutrients: Vitamin E (alpha-tocopherol) ~15mg (100% RDI), a primary fat-soluble [antioxidant](/ingredients/condition/antioxidant) with high bioavailability due to fat matrix; Manganese ~6.2mg (~270% RDI); Copper ~1.7mg (~190% RDI); Magnesium ~163mg (~39% RDI); Phosphorus ~290mg (~29% RDI); Potassium ~680mg (~19% RDI); Iron ~4.7mg (~26% RDI, non-heme, absorption enhanced by co-ingested vitamin C); Zinc ~2.4mg (~22% RDI); Calcium ~114mg (~11% RDI, bioavailability reduced by oxalate content ~0.1g/100g); B vitamins: thiamine (B1) ~0.64mg (~53% RDI), folate ~113μg (~28% RDI), B6 ~0.56mg (~32% RDI). Bioactive compounds: Beta-sitosterol ~96mg/100g (phytosterol with LDL-lowering potential, intestinal absorption ~5-10%); proanthocyanidins ~500mg/100g (condensed tannins concentrated in skin, bioavailability limited, undergo colonic fermentation); taxifolin and myricetin glycosides present in skin; chlorogenic acid ~20-30mg/100g; total polyphenols ~495mg GAE/100g (predominantly in brown skin; blanched/roasted hazelnuts show 30-50% reduction in polyphenol content). Phytic acid ~0.6-0.9g/100g reduces mineral bioavailability (zinc, iron, calcium) by 10-50%; roasting partially degrades phytate. Hazelnut oil contains squalene ~300-500mg/100g oil. Allergen note: Cor a 1, Cor a 8, Cor a 9, Cor a 11, and Cor a 14 are major allergen proteins; Cor a 14 (2S albumin) is heat-stable and associated with severe reactions.

## Dosage & Preparation

No clinically studied dosage ranges have been established for hazelnut extracts, powders, or standardized forms as human trials are absent. In vitro studies used crude extracts or isolated compounds without doses translatable to human use. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Hazelnut is one of the most common tree nut allergens, with reactions ranging from oral allergy syndrome (mild itching, swelling) to anaphylaxis, particularly in individuals sensitized to birch pollen via cross-reactive Bet v 1 proteins. People taking anticoagulants such as warfarin should use caution, as hazelnut's vitamin K content may modestly affect INR levels with very high intake. Hazelnut is generally regarded as safe during pregnancy when consumed as a food, though concentrated extracts or supplements have not been evaluated for safety in pregnant or lactating women. No significant drug interactions have been documented at typical dietary amounts, but individuals with tree nut allergies must strictly avoid all hazelnut-containing products.

## Scientific Research

No human clinical trials, RCTs, or meta-analyses on hazelnut kernel for biomedical applications were identified (searched PubMed PMIDs: 33822614, 18316150). All available evidence is limited to in vitro studies showing [COX-2](/ingredients/condition/inflammation) inhibition, [antimicrobial](/ingredients/condition/immune-support) activity, and [antioxidant](/ingredients/condition/antioxidant) effects using isolated compounds or crude extracts.

## Historical & Cultural Context

No historical or traditional medicinal uses of hazelnut kernels in specific systems like Ayurveda or TCM were documented in the available sources. Hazelnut has been primarily valued as a nutritious food source for its high fat content and oleic acid rather than as a medicinal remedy.

## Synergistic Combinations

Vitamin E, Omega-3 fatty acids, Green tea extract, Resveratrol, Quercetin

## Frequently Asked Questions

### How much hazelnut should I eat per day for health benefits?

Human studies showing cardiovascular benefits typically used 30–57 grams (approximately 1–2 ounces or a small handful) of hazelnuts daily incorporated into a balanced diet. This amount provides roughly 178 calories, 17g of monounsaturated fat, 4.2mg of vitamin E (alpha-tocopherol), and meaningful amounts of magnesium and manganese. No standardized therapeutic dose exists for hazelnut supplements, as most evidence comes from whole food consumption.

### Does hazelnut reduce inflammation?

In vitro studies show hazelnut leaf and kernel extracts inhibit COX-2 enzyme activity by 36–64%, reducing prostaglandin E2 production, a key inflammatory mediator. The polyphenols taxifolin, quercetin, and kaempferol are the primary compounds responsible for this effect. However, these results come exclusively from cell culture studies, and direct anti-inflammatory effects in human clinical trials have not yet been confirmed with robust evidence.

### Are hazelnuts good for cholesterol?

Small human studies suggest that substituting dietary fats with hazelnut-derived fats can reduce LDL cholesterol by approximately 5–10% over 4–8 weeks in adults with elevated baseline cholesterol. This effect is largely attributed to oleic acid (monounsaturated fat), which comprises up to 83% of hazelnut's fatty acid profile, and beta-sitosterol, which competitively inhibits cholesterol absorption in the gut. These findings are consistent with broader research on tree nuts but require replication in larger trials.

### Can people with tree nut allergies eat hazelnuts?

No — hazelnut is among the most allergenic tree nuts and must be strictly avoided by individuals with confirmed hazelnut or tree nut allergies. The primary allergen proteins include Cor a 1 (a Bet v 1 homolog cross-reactive with birch pollen), Cor a 8 (a lipid transfer protein), and Cor a 9 (an 11S globulin storage protein). Reactions can range from oral allergy syndrome with mild mucosal itching to severe systemic anaphylaxis requiring epinephrine intervention.

### What antioxidants are in hazelnuts?

Hazelnuts contain alpha-tocopherol (vitamin E) at approximately 15mg per 100g, making them one of the richest dietary sources of this fat-soluble antioxidant. They also contain polyphenols including proanthocyanidins, quercetin, kaempferol, and taxifolin concentrated primarily in the brown skin, which demonstrate strong DPPH and ABTS radical scavenging activity in vitro. Myricetin and caffeic acid derivatives contribute additional antioxidant capacity, with skin-on hazelnuts providing significantly higher total phenolic content than blanched varieties.

### Is hazelnut safe for pregnant and breastfeeding women?

Hazelnuts are generally recognized as safe for consumption during pregnancy and breastfeeding as a whole food, providing beneficial nutrients like folate and healthy fats that support fetal development. However, pregnant women with tree nut allergies or a family history of nut allergies should consult their healthcare provider before consumption. No specific safety concerns exist for hazelnut supplementation in these populations, though moderation is advisable as with all foods.

### Does hazelnut interact with blood thinners or antiplatelet medications?

Hazelnuts contain vitamin K, which plays a role in blood clotting, so individuals taking warfarin or other anticoagulants should maintain consistent hazelnut intake rather than dramatically increasing or decreasing consumption. Whole hazelnut consumption as food is unlikely to cause clinically significant interactions, though high-dose hazelnut supplements warrant discussion with a healthcare provider. Those on antiplatelet medications should not be concerned about typical dietary hazelnut consumption.

### What does the current research evidence show about hazelnut's antimicrobial benefits?

In vitro laboratory studies demonstrate that hazelnut extracts show antimicrobial activity against certain Gram-positive bacteria and Candida albicans, but this evidence is preliminary and has not been validated in human clinical trials. The concentrations of hazelnut extract used in these studies (0.1 mg/mL MIC values) are significantly higher than what typical dietary consumption would provide. Current evidence is insufficient to recommend hazelnuts as a treatment for bacterial or fungal infections in humans.

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*Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com*
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