grape skin and grape seed extracts
Also known as: Vitis vinifera, Grape seed extract (GSE), Grape skin extract, Grape polyphenols
Overview
Grape seed and skin extracts are derived from the seeds and skins of grapes, typically *Vitis vinifera*. These extracts are created through drying and solvent extraction to concentrate polyphenolic compounds such as proanthocyanidins and resveratrol. They are by-products of the wine and juice industry and are primarily used for their antioxidant and anti-inflammatory properties. These extracts are marketed to support cardiovascular health, reduce oxidative stress, improve metabolic profiles, and potentially modulate inflammation. Rich in polyphenols, especially proanthocyanidins, they have potent free radical scavenging activity. They are considered bioactive botanical supplements with potential systemic effects. Research maturity is moderate to advanced, with numerous randomized controlled trials (RCTs) and several systematic reviews/meta-analyses, though some outcomes remain inconclusive or modest. Evidence includes multiple RCTs with adequate sample sizes and meta-analyses, but heterogeneity in study designs, doses, and populations leads to some variability in conclusions.
Benefits
Grape seed and skin extracts offer several evidence-based benefits. They significantly reduce oxidative stress biomarkers like malondialdehyde (SMD: -1.04; 95% CI: -1.65, -0.42) and oxidized LDL (SMD: -0.44; 95% CI: -0.75, -0.13). These extracts also decrease the inflammatory marker high-sensitivity C-reactive protein (hs-CRP) (WMD: -0.48 mg/L; 95% CI: -0.94, -0.03). Meta-analyses report improvements in lipid profiles, including reductions in total cholesterol, LDL cholesterol, and triglycerides. Some studies show modest increases in total antioxidant capacity (SMD: 0.49; 95% CI: -0.05, 1.04). Potential blood pressure modulation depends on baseline blood pressure levels. Benefits are observed in adults with prehypertension, metabolic syndrome, or cardiovascular risk factors. Clinical trials ranged from 2 to 25 weeks, with benefits observed within this timeframe.
How it works
Grape seed and skin extracts primarily work through antioxidant activity by scavenging free radicals and inhibiting lipid peroxidation. They also exert anti-inflammatory effects via downregulation of pro-inflammatory cytokines and CRP. In the cardiovascular system, they improve endothelial function, reduce LDL oxidation, and modulate lipid metabolism. In the metabolic system, they may influence glucose metabolism and insulin sensitivity. Known molecular targets include reactive oxygen species (ROS), LDL particles, and inflammatory mediators such as CRP. Polyphenols from grape extracts have variable bioavailability; proanthocyanidins are metabolized by gut microbiota, influencing systemic effects.
Side effects
Grape seed and skin extracts are generally regarded as safe with a low incidence of adverse effects in clinical trials. Common side effects (>5%) include mild gastrointestinal discomfort. Uncommon side effects (1-5%) may include headache and dizziness in some cases. Rare side effects (<1%) include allergic reactions. Potential interactions with anticoagulants due to mild blood-thinning effects warrant caution. Limited data suggests caution in pregnancy, breastfeeding, and bleeding disorders. Safety in children and pregnant women is not well established. It is important to consult with a healthcare provider before using grape seed or skin extract, especially if you have any pre-existing medical conditions or are taking medications.
Dosage
The minimum effective dose is approximately 100 mg of grape seed proanthocyanidin extract daily. Optimal dosage ranges from 100 mg to 2,000 mg per day in clinical studies, with 200-600 mg commonly used for antioxidant effects. Up to 2,000 mg/day appears safe in short-term studies, but long-term safety data is limited. There are no strict timing recommendations; often taken with meals to improve absorption. Extracts standardized for polyphenol content are preferred for consistent dosing. Bioavailability is influenced by food matrix and gut microbiota; co-administration with fats may enhance absorption. No specific cofactors are required, but overall nutritional status may affect efficacy.
FAQs
Is grape seed and skin extract safe for daily use?
Yes, it is generally safe with minimal side effects reported in clinical trials. However, consult with a healthcare provider if you have any underlying health conditions.
How soon can benefits be expected?
Benefits on oxidative stress and inflammation markers have been observed within 2 to 16 weeks of consistent supplementation.
Does it help with blood pressure?
Effects on blood pressure may depend on baseline levels; some evidence suggests modest reductions in prehypertensive individuals.
Can it replace medications for cholesterol or diabetes?
No, it may support but not replace standard treatments; consult healthcare providers for appropriate medical advice.
Are grape seed and skin extracts the same?
They share similar polyphenols but differ in specific composition; both have antioxidant properties and potential health benefits.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7971097/ – This systematic review and meta-analysis of 17 RCTs (n=633) evaluated the impact of grape products containing polyphenols on oxidative stress markers. The study found partial improvement in oxidative stress status but noted inconclusive results due to heterogeneity in study quality and interventions, highlighting the need for further well-designed trials.
- https://pubmed.ncbi.nlm.nih.gov/34107109/ – This systematic review and meta-analysis of 23 studies (19 in meta-analysis) examined the effects of grape seed extract supplementation on oxidative stress and inflammation biomarkers. The study reported significant decreases in malondialdehyde, oxidized LDL, and hs-CRP, along with a marginal increase in total antioxidant capacity, suggesting potential benefits for reducing oxidative stress and inflammation.
- https://www.mdpi.com/2304-8158/9/11/1627 – This meta-analysis of 15 RCTs assessed the effects of grape seed extract on glycemic control, serum lipoproteins, inflammation, and body weight. The study found significant reductions in fasting plasma glucose, total cholesterol, LDL cholesterol, triglycerides, and CRP, indicating potential benefits for metabolic and cardiovascular health.
- https://onlinelibrary.wiley.com/doi/10.1111/ijcp.14469 – This study investigated the effects of grape seed extract on cardiovascular risk factors. The results suggest that grape seed extract may have a beneficial impact on blood pressure and other cardiovascular parameters, particularly in individuals with pre-existing risk factors.
- https://www.nutraingredients-latam.com/Article/2020/01/13/Meta-analysis-supports-grape-seed-extract-s-cardiovascular-potential/ – This article summarizes a meta-analysis supporting the cardiovascular potential of grape seed extract. The meta-analysis suggests that grape seed extract may contribute to improved cardiovascular health by positively influencing various risk factors.
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