Red Wine Concentrates
Also known as: Red wine polyphenols (RWP), Red wine extract, Grape seed extract, Grape polyphenols, 3,5,4'-trihydroxy-trans-stilbene, Resveratrol
Overview
Red wine concentrates are supplements derived from red wine or grape extracts, primarily from *Vitis vinifera* grapes. They are rich in a complex mixture of polyphenolic compounds, including resveratrol, flavonoids, and proanthocyanidins, which are naturally found in the skins and seeds of red grapes. These supplements are mainly utilized for their potential to support cardiovascular health, particularly in improving vascular function and reducing blood pressure. They are also investigated for their antioxidant and anti-inflammatory properties. While the bioavailability of these compounds can vary, research indicates a moderate to advanced understanding of their effects, with several randomized controlled trials and meta-analyses supporting their use, especially for vascular outcomes. The evidence quality is generally high, though human effects are often less pronounced than those observed in animal models.
Benefits
Red wine concentrates, particularly their polyphenol components, offer several evidence-based benefits. The most significant effect observed is a modest reduction in systolic blood pressure (SBP), with meta-analyses showing an average decrease of approximately 2.6 mmHg in humans. Studies focusing on pure resveratrol have shown a slightly greater effect, with reductions of around 3.7 mmHg. While improvements in vascular function measures like flow-mediated dilation (FMD) have not been consistently significant in human studies, there is supporting evidence for antioxidant and anti-inflammatory effects, indicated by reductions in oxidative stress markers. These benefits appear to be more pronounced in at-risk populations, such as individuals with hypertension or vascular dysfunction, rather than in healthy individuals. The modest reduction in SBP, while smaller than that achieved by typical antihypertensive drugs, can still contribute to cardiovascular risk reduction. Benefits typically manifest after several weeks of consistent use, with average study durations around 8.5 weeks.
How it works
Red wine concentrates exert their effects primarily through antioxidant activity, which helps reduce oxidative stress in the body. They also modulate endothelial nitric oxide synthase (eNOS), leading to enhanced nitric oxide (NO) availability. Increased NO promotes vasodilation, thereby improving vascular function and reducing blood pressure. Additionally, these polyphenols possess anti-inflammatory properties, achieved through the downregulation of pro-inflammatory cytokines and inhibition of pathways like NF-κB. They interact primarily with the vascular endothelium to facilitate vasodilation and reduce blood pressure. Key molecular targets include eNOS and NADPH oxidase. It's important to note that resveratrol and other polyphenols have limited bioavailability due to rapid metabolism, which can influence their efficacy.
Side effects
Red wine concentrates are generally considered safe and well-tolerated at doses typically used in clinical studies. Common side effects, reported occasionally, include mild gastrointestinal discomfort. Less common side effects (occurring in 1-5% of individuals) may include headache and dizziness. Serious adverse events are rare, with no significant occurrences reported in high-quality trials. However, caution is advised regarding potential drug interactions, particularly with anticoagulants, due to the mild blood-thinning effects of some components. Contraindications are not extensively documented, but due to a lack of sufficient safety data, caution is recommended for pregnant and breastfeeding individuals. The effects and safety in children and severely ill populations have not been well studied.
Dosage
For optimal benefits, particularly for vascular health, a dosage range of approximately 150-500 mg/day of resveratrol or an equivalent amount of polyphenols from red wine concentrates is often recommended. Human studies have utilized resveratrol doses ranging from 100 to 500 mg/day. While doses up to 1 gram/day of resveratrol have been used safely in some trials, the long-term safety at this higher dose is not yet fully established. Dosing is typically once daily, and there are no specific timing recommendations relative to meals, although co-administration with fats may improve absorption. For consistency and efficacy, extracts standardized for their resveratrol content are preferred. No specific cofactors are required for their absorption or activity.
FAQs
Are red wine concentrates safe without alcohol?
Yes, most supplements are alcohol-free extracts, containing only the beneficial polyphenols, and are safe for consumption without the intoxicating effects of alcohol.
Can red wine concentrates replace blood pressure medication?
No, while they may offer modest support in lowering blood pressure, they are not a substitute for prescribed antihypertensive medications. Always consult your doctor before making changes to your medication.
How long before effects are seen?
Benefits on blood pressure and other vascular markers are typically observed after several weeks of consistent daily use, often within 4 to 8 weeks.
Do they cause intoxication?
No, these supplements contain only the beneficial polyphenols from red wine or grapes and do not contain alcohol, so they will not cause intoxication.
Is resveratrol the only active compound?
No, while resveratrol is a key active compound, red wine concentrates contain a complex mixture of other polyphenols, such as flavonoids and proanthocyanidins, which also contribute to their beneficial effects.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7867547/ – This systematic review and meta-analysis, published in 2021, analyzed 37 human randomized controlled trials. It found that red wine polyphenols (RWP) significantly reduced systolic blood pressure by 2.6 mmHg, with pure resveratrol showing a stronger effect. However, no significant effect was observed on diastolic blood pressure or flow-mediated dilation, highlighting the modest but specific cardiovascular benefits.
- https://pubmed.ncbi.nlm.nih.gov/32303823/ – This systematic review from 2020, encompassing 48 animal and 37 human studies, investigated the effects of red wine polyphenols. It concluded that while animal studies consistently showed vascular benefits, human effects were more modest but still significant for systolic blood pressure, indicating a translational gap between animal and human data.
- https://onlinelibrary.wiley.com/doi/10.1155/2024/5086541 – This systematic review and meta-analysis, published in 2024, focused on grape products and their impact on inflammation and oxidative stress markers. It found that grape products, including red wine concentrates, can reduce these markers, suggesting antioxidant and anti-inflammatory properties, although the clinical significance of these findings requires further investigation.