Grape Seed (Vitis vinifera)

Quick Summary

Grape seed, derived from Vitis vinifera, contains bioactive compounds such as polyphenols and oligomeric proanthocyanidins. Current research is investigating its potential benefits across various health areas including cognitive function, metabolic disorders like diabetes, cardiovascular health, oral health, adjunctive cancer therapy, and gut microbiota modulation. Evidence also highlights antioxidant and anti-inflammatory properties. While clinical trials are ongoing, most evidence remains preliminary with some limitations in study design and size.

What is it?

Grape seed extract is obtained from the seeds of the grape plant, Vitis vinifera. It is rich in polyphenolic compounds including oligomeric proanthocyanidins, which are believed to contribute to its biological activities.

Traditional Uses

Traditionally, grape seeds have been used for their purported benefits in supporting vascular and cardiovascular health, as well as general antioxidant support.

Active Compounds

Polyphenols
Oligomeric proanthocyanidins (OPCs)
Resveratrol (also found in grapes broadly)

Potential Benefits with Evidence Levels

Cognitive function in older adults: Preliminary clinical evidence from network meta-analyses suggests that raisin (dried grape) ranks highly among plant substances for learning and memory functions in healthy older adults, indicating potential cognitive benefits of grape-derived products.^[1]
Renal biomarkers in type 2 diabetes: Moderate clinical evidence indicates that resveratrol, a grape polyphenol, may modestly reduce serum uric acid in patients with type 2 diabetes, although effects on blood urea nitrogen and serum creatinine were not significant.^[2]
Impaired fasting blood glucose and lipid metabolism: A randomized controlled trial reported improvement in fasting glycemia and lipid profiles with a supplement containing Vitis vinifera extracts over six months in individuals with impaired fasting glucose.^[3]
Chronic venous disease: Expert consensus considers preparations including grape seed extract as reasonable first-line conservative management options for chronic venous disease symptoms.^[4]
Cancer cachexia adjunctive management: Preclinical and emerging clinical evidence suggests grape seed polyphenols may modulate pathways involved in cachexia and support nutritional status, with ongoing clinical trials.^[5]
Dental caries prevention: Preliminary clinical evidence indicates grape seed extract may have antimicrobial effects and enamel surface hardening properties that could help prevent dental caries, though further research is needed.^[6]
Oral squamous cell carcinoma: Preclinical studies show potential anti-proliferative and pro-apoptotic effects of grape extracts against oral squamous cell carcinoma cells in vitro and in animal models.^[7]
Gut microbiota modulation and oxidative stress: Systematic review and meta-analysis evidence suggests polyphenol-rich interventions including grape polyphenols may improve gut barrier function and antioxidant defenses in overweight or obese adults; effects on body weight and inflammation remain inconclusive.^[8]
Antioxidant and anti-inflammatory support: Reviews and meta-analyses indicate grape seed polyphenols have antioxidant and anti-inflammatory properties that may support cardiovascular and metabolic health, although variability in study results and bioavailability challenges limit firm clinical recommendations.^[9]

Side Effects

Grape seed extracts are generally well tolerated in clinical studies with no serious adverse effects reported. No significant adverse effects or toxicity have been consistently observed. Some isolated animal studies suggest caution, but human data are insufficient to clearly identify specific risks.

Drug Interactions

No definitive clinical evidence currently indicates drug interactions with grape seed extracts. However, due to the polyphenol content, potential interactions affecting cytochrome P450 enzymes or drug transport proteins cannot be fully excluded and warrant further investigation.

Who Should Avoid It

Individuals with bleeding disorders or those taking anticoagulant medications may want to exercise caution due to possible effects of polyphenols on blood clotting, although clinical data on this are lacking. Safety during pregnancy and breastfeeding has not been established; therefore, use is not recommended in these populations without further safety data from controlled studies.

Evidence Limitations

Most clinical trials are small, short-term, or lack rigorous design.
There is heterogeneity in grape preparations, dosages, and concurrent use with other agents, which limits comparability.
Variation in bioavailability and metabolism of grape polyphenols impacts clinical outcomes.
More large-scale, well-controlled randomized clinical trials are needed to confirm benefits and safety.
Preclinical evidence predominates for certain indications such as oncology and cachexia, with clinical translation still pending.

References

Last Reviewed

June 2024

Informational disclaimer: This page is for informational purposes only and is not intended to provide medical advice, diagnose, treat, or cure any health conditions. Always consult a qualified healthcare provider before starting any new supplement or herbal regimen, especially if you are pregnant, breastfeeding, taking medications, or have a medical condition.