# Walnut (Juglans regia) **Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/walnut **Data Source:** Hermetica Superfoods Ingredient Encyclopedia **Updated:** 2026-03-29 **Evidence Score:** 2 / 10 **Category:** European **Also Known As:** English walnut, Persian walnut, Carpathian walnut, Common walnut, Royal walnut, Madeira nut, California walnut ## Overview Walnut (Juglans regia) contains high concentrations of polyphenolic compounds including ellagic acid and juglone that provide antioxidant and [antimicrobial](/ingredients/condition/immune-support) activity. These bioactive compounds work through [free radical scaveng](/ingredients/condition/antioxidant)ing mechanisms and demonstrate significant DPPH/ABTS activity in laboratory studies. ## Health Benefits • [Antioxidant activity](/ingredients/condition/antioxidant) evidenced by high DPPH/ABTS scavenging capacity from in vitro studies using green husk extracts. • Antifungal properties demonstrated in vitro, with supercritical CO₂ husk extracts showing activity against fungi. • [Antimicrobial](/ingredients/condition/immune-support) potential observed in vitro, though human data is lacking. • Rich in polyphenols, contributing to the overall antioxidant effects. • Juglone content provides potential bioactivity, though its specific health effects in humans remain untested. ## Mechanism of Action Walnut's polyphenolic compounds, particularly ellagic acid and juglone, neutralize free radicals through electron donation and hydrogen atom transfer mechanisms. The [antimicrobial](/ingredients/condition/immune-support) effects occur via disruption of fungal cell membrane integrity and inhibition of microbial enzyme systems. These compounds also modulate [oxidative stress](/ingredients/condition/antioxidant) pathways by enhancing endogenous antioxidant enzyme activity. ## Clinical Summary Current evidence is limited to in vitro studies demonstrating [antioxidant activity](/ingredients/condition/antioxidant) through DPPH and ABTS assays using green husk extracts. Laboratory studies show antifungal properties against various fungi species using supercritical CO₂ extraction methods. [Antimicrobial](/ingredients/condition/immune-support) activity has been observed in controlled laboratory conditions, but human clinical trials are lacking. The evidence strength remains preliminary without human intervention studies. ## Nutritional Profile Walnuts (Juglans regia) per 100g edible kernel: Macronutrients — Fat 65.2g (predominantly polyunsaturated fatty acids: linoleic acid/omega-6 ~38g, alpha-linolenic acid/omega-3 ~9g, oleic acid/omega-9 ~14g); Protein 15.2g (containing all essential amino acids, notably arginine ~2.3g); Carbohydrates 13.7g; Dietary fiber 6.7g; Energy ~654 kcal. Micronutrients — Manganese 3.4mg (170% DV), Copper 1.6mg (178% DV), Magnesium 158mg (40% DV), Phosphorus 346mg (35% DV), Zinc 3.1mg (28% DV), Iron 2.9mg (16% DV), Calcium 98mg (10% DV), Potassium 441mg (13% DV), Selenium 4.9µg. Vitamins — Vitamin E (gamma-tocopherol dominant at ~21mg, alpha-tocopherol ~0.7mg; note gamma-tocopherol bioavailability is lower than alpha form), Vitamin B6 0.54mg (32% DV), Folate 98µg (25% DV), Thiamine 0.34mg (28% DV), Vitamin K 2.7µg. Bioactive compounds — Total polyphenols ~1575mg GAE/100g (kernels); ellagitannins including pedunculagin and tellimagrandin (hydrolyzed to ellagic acid in gut, further converted to urolithins by gut microbiota — bioavailability highly individual); juglone (5-hydroxy-1,4-naphthoquinone) concentrated primarily in green husks and pellicle (~0.02–0.1% in husk dry weight, trace amounts in kernel pellicle); gallic acid; catechins; quercetin glycosides; melatonin (~3.5ng/g). Green husk specific — Significantly higher juglone concentration (up to 2–4% dry weight reported in some extracts); naphthoquinone derivatives; tannins up to 12% dry weight; ascorbic acid ~300–500mg/100g fresh husk. Bioavailability notes — ALA-to-EPA/DHA conversion is limited (~5–10% to EPA, <1% to DHA); ellagitannin conversion to urolithins depends on [gut microbiome](/ingredients/condition/gut-health) composition (urolithin producers vs. non-producers); fat-soluble compounds absorption enhanced when consumed with the native walnut fat matrix; phytic acid content (~0.98g/100g) may reduce mineral bioavailability by 10–50% depending on preparation method. ## Dosage & Preparation No clinically studied dosage ranges are available due to the absence of human trials. Consult a healthcare provider before starting any new supplement. ## Safety & Drug Interactions Walnut supplements may cause allergic reactions in individuals with tree nut allergies, potentially including anaphylaxis. No specific drug interactions have been documented, but theoretical interactions may occur with anticoagulant medications due to potential effects on bleeding time. Pregnancy and breastfeeding safety data is insufficient for supplemental doses beyond normal dietary intake. Gastrointestinal upset may occur with high doses of concentrated extracts. ## Scientific Research There are no human clinical trials, RCTs, or meta-analyses available for Juglans regia extracts. Evidence is limited to in vitro studies, with no specific PubMed PMIDs provided. ## Historical & Cultural Context The research does not specify traditional medicine systems or historical uses for Juglans regia. Modern interest focuses on utilizing the green husk for its bioactive compounds with [antioxidant](/ingredients/condition/antioxidant) and [antimicrobial](/ingredients/condition/immune-support) properties. ## Synergistic Combinations Green tea extract, resveratrol, vitamin C, curcumin, quercetin ## Frequently Asked Questions ### What is the active compound in walnut extract? The primary active compounds are polyphenols including ellagic acid, juglone, and tannins. These compounds are concentrated in the green husk and provide the antioxidant and antimicrobial properties. ### How much walnut extract should I take daily? No standardized dosage exists due to lack of human studies. Laboratory studies used various concentrations of husk extracts, but safe and effective human doses have not been established through clinical trials. ### Can walnut extract help with fungal infections? In vitro studies show antifungal activity against various fungi species using supercritical CO₂ husk extracts. However, no human studies have tested walnut extract for treating fungal infections in people. ### Is walnut extract safe with blood thinners? No specific interactions are documented, but theoretical concerns exist due to potential effects on bleeding. Consult your healthcare provider before combining walnut supplements with anticoagulant medications like warfarin. ### What's the difference between eating walnuts and walnut extract? Walnut extracts concentrate specific compounds like polyphenols from the husk, while whole walnuts provide healthy fats, protein, and fiber. Most research focuses on concentrated husk extracts rather than the edible nut portions. ### What is juglone and why is it important in walnut supplements? Juglone is a naturally occurring naphthoquinone compound found primarily in walnut husks and green walnuts, known for its antimicrobial and antifungal properties. This polyphenolic compound contributes significantly to walnut extract's bioactivity and is often concentrated in supercritical CO₂ extracts used in supplements. While juglone demonstrates in vitro activity against various pathogens, most evidence remains laboratory-based and human clinical data is limited. ### Which form of walnut supplement has the strongest antioxidant potency? Green husk extracts and supercritical CO₂ extracts demonstrate the highest antioxidant capacity in laboratory studies, as measured by DPPH and ABTS free radical scavenging assays. These concentrated forms contain elevated polyphenol levels compared to whole walnut supplements or standard dried extracts. However, research on bioavailability and effectiveness in human subjects remains limited, so the practical superiority of one form over another has not been conclusively established. ### Are there any populations that should be cautious about walnut supplement use? Individuals with tree nut allergies should avoid walnut supplements entirely, as allergic cross-reactivity is possible even with extract forms. Pregnant and nursing women should consult healthcare providers before supplementation, as safety data specifically in these populations is not well-established. People taking anticoagulant medications may need medical guidance, since walnuts contain compounds that could theoretically affect clotting, though clinical evidence of interaction is limited. --- *Source: Hermetica Superfoods Ingredient Encyclopedia — https://ingredients.hermeticasuperfoods.com* *License: CC BY-NC-SA 4.0 — Attribution required. Commercial use: admin@hermeticasuperfoods.com*