Walnut Extract
Also known as: Juglans regia, Juglans nigra, English walnut, black walnut, Walnut, walnut extract, walnut oil, walnut kernel
Overview
Walnut extract is derived from the kernels of walnuts, primarily *Juglans regia*, and is available as whole nuts, oil, or standardized extracts. It is commonly used to support cardiovascular health, manage lipid profiles, and as an anti-inflammatory agent. Walnuts are rich in omega-3 fatty acids (ALA), antioxidants, and bioactive polyphenols. Research on walnut extract is considered moderately to highly mature, with several systematic reviews and meta-analyses available. The quality of evidence is generally good, supported by multiple randomized controlled trials (RCTs) and meta-analyses, although some variability exists in study designs and outcomes. Its high content of polyunsaturated fatty acids, especially alpha-linolenic acid, along with polyphenols, tocopherols, phytosterols, and melatonin, contributes to its health-promoting properties.
Benefits
Walnut extract is primarily known for improving lipid profiles. Systematic reviews and meta-analyses consistently show that walnut consumption reduces total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C). Studies have reported significant reductions in TC (mean difference: -6.99 mg/dL, 95% CI: -9.39 to -4.60) and LDL-C (mean difference: -5.51 mg/dL, 95% CI: -7.72 to -3.30). These lipid improvements are associated with a reduced risk of cardiovascular disease (CVD). Secondary benefits include anti-inflammatory effects, although evidence is not as consistent. Some data suggest potential hepatic protection, reducing hepatic inflammation and toxicity, but this is primarily from animal studies. Individuals with abnormal glucose homeostasis may experience modest improvements in lipid profiles, but not in glucose control. The lipid changes typically occur within 4–12 weeks of daily intake.
How it works
Walnut extract exerts its effects through several biological pathways. The polyunsaturated fatty acids (PUFAs), especially alpha-linolenic acid (ALA), modulate hepatic lipid synthesis and increase LDL receptor activity, thereby reducing circulating LDL-C levels. The polyphenols and tocopherols present in walnuts act as antioxidants, reducing oxidative stress and inflammation. Walnut consumption can modulate inflammatory cytokines and pathways, contributing to its anti-inflammatory effects. In the cardiovascular system, it improves endothelial function and reduces atherogenesis. It may also reduce hepatic inflammation and oxidative stress. At the molecular level, walnut components can inhibit lipid synthesis enzymes like HMG-CoA reductase and reduce inflammatory mediators such as TNF-α and IL-6.
Side effects
Walnut extract is generally safe for most adults at typical dietary doses. Common side effects are rare, but some individuals may experience mild gastrointestinal discomfort. Uncommon side effects (1-5%) include allergic reactions, particularly in those with nut allergies. Severe allergic reactions, such as anaphylaxis, are rare but possible. There are no significant drug interactions reported, although there is a theoretical risk with anticoagulants due to the omega-3 content. Walnut extract is contraindicated for individuals with a known walnut allergy. It is considered safe in pregnancy and lactation at dietary levels, but caution is advised for individuals with nut allergies. Individuals on anticoagulant medications should monitor their blood clotting parameters when starting walnut supplementation.
Dosage
The minimum effective dose of whole walnuts is approximately 30 g/day (about 1 ounce). Optimal dosage ranges for lipid benefits are between 30–60 g/day. A maximum safe dose has not been definitively established, but studies have used up to 100 g/day without significant adverse effects. Walnut extract can be consumed at any time of day, but consistent daily intake is recommended for optimal results. Whole nuts are preferred for their fiber and polyphenol content, but extracts and oils can be used for convenience. Absorption of the beneficial compounds is enhanced when consumed with meals containing fat. No specific cofactors are required for walnut extract to be effective.
FAQs
Who should avoid walnut extract?
Individuals with known nut allergies should avoid walnut extract due to the risk of allergic reactions. Those on anticoagulant medications should monitor their blood clotting parameters.
What is the best form of walnut to consume?
Whole walnuts are generally preferred as they provide additional fiber and micronutrients compared to extracts or oils. However, extracts and oils can be a convenient alternative.
How long does it take to see results from taking walnut extract?
Modest reductions in total cholesterol (TC) and LDL-C can typically be observed within 1–3 months of consistent daily consumption.
Are there any drug interactions with walnut extract?
No significant drug interactions have been reported, but there is a theoretical risk with anticoagulants due to the omega-3 content. Monitor if on anticoagulants.
Is walnut extract a cure-all for heart disease?
No, walnut extract provides modest benefits and should complement other lifestyle interventions such as a healthy diet and regular exercise.
Research Sources
- https://www.mdpi.com/2072-6643/14/21/4460 – This systematic review and meta-analysis examined the effects of walnut intake on lipid profiles. The study found that walnut intake significantly reduced total cholesterol (TC) and LDL-C, suggesting a beneficial impact on cardiovascular health. The analysis included multiple RCTs with a sample size of n ≥ 30 per group and a duration of 4–52 weeks.
- https://onlinelibrary.wiley.com/doi/full/10.1002/fsn3.4405 – This review discusses the potential of walnut extract in reducing hepatic inflammation. While primarily based on animal studies, the review suggests that walnut extract may offer benefits for hepatic health by reducing inflammation and toxicity. However, the authors note that more high-quality human RCTs are needed to confirm these findings.
- https://academic.oup.com/nutritionreviews/article/81/1/26/6651942 – This article reviews the impact of walnut consumption on cardiometabolic profiles. The review highlights that walnut intake is associated with improved lipid profiles and a reduced risk of cardiovascular disease. The findings support the inclusion of walnuts as part of a heart-healthy diet.
- https://www.mdpi.com/2076-3921/11/7/1412 – This study investigates the anti-inflammatory properties of walnut extract. The research suggests that walnut consumption can modulate inflammatory cytokines and pathways, contributing to its anti-inflammatory effects. The study provides evidence for the potential of walnuts in reducing inflammation-related health issues.
- https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/effect-of-walnut-consumption-on-cardiometabolic-profiles-of-individuals-with-abnormal-glucose-homoeostasis-a-systematic-review-and-metaanalysis-of-clinical-trials/8A5D8AA04B7825F4476898B34F77040E – This systematic review and meta-analysis focuses on the effect of walnut consumption on cardiometabolic profiles in individuals with abnormal glucose homeostasis. The study found modest improvements in lipid profiles but no significant effect on glucose homeostasis. The analysis included multiple RCTs with a sample size of n ≥ 30 per group and a duration of 4–24 weeks.
Recommended Articles
Herbal Boosters & COVID-19 Antivirals: Safe Mix?
Herbal supplements may interact with COVID-19 antivirals, requiring careful consideration and further research.
Top Immune Support Ingredients: What Works?
Vitamin D, zinc, and echinacea are key ingredients in immune support supplements, backed by scientific evidence.
Top Anti-Inflammatory Supplement Ingredients
Curcumin, omega-3 fatty acids, CBD, and Vitamin D are proven to effectively reduce chronic inflammation.
Best Supplements for Cortisol Reduction: A Scientific Guide
Adaptogens like Ashwagandha and Rhodiola, along with Phosphatidylserine, are effective in reducing cortisol levels, supported by scientific studies.