Is Grape Seed Extract safe?
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Safety of Grape Seed Extract: A Comprehensive Review
Introduction to Grape Seed Extract Safety
Grape seed extract (GSE) is widely recognized for its health benefits, including antioxidant, anti-inflammatory, and antimicrobial properties. However, its safety profile is crucial for its use as a dietary supplement and in food products. This article synthesizes findings from multiple studies to evaluate the safety of GSE.
90-Day Oral Toxicity in Rats
A 90-day oral toxicity study on Sprague-Dawley rats assessed the safety of GSE with less than 5.5% catechin monomers. Rats were fed diets containing 0.5%, 1.0%, or 2.0% GSE. The study found no significant changes in clinical signs, hematological parameters, organ weights, ophthalmology evaluations, or histopathological findings. Although male rats in the high-dose group exhibited decreased serum iron levels, these values remained within historical ranges for the species. The study concluded that GSE did not induce significant toxicological effects at the tested levels.
4-Week Oral Intake in Humans
A clinical study involving healthy Japanese adults evaluated the safety of proanthocyanidin-rich GSE over four weeks. Participants consumed daily doses of 1000, 1500, or 2500 mg. While two subjects in the highest dose group experienced a temporary decrease in serum iron levels, these levels returned to near baseline after the study. No participants discontinued the study, indicating that GSE up to 2500 mg per day is generally safe and well-tolerated in humans.
Subchronic Toxicity Studies
Subchronic toxicity studies on Fischer 344 rats involved administering GSE at levels of 0.02%, 0.2%, and 2% in the diet for 90 days. The studies found no evidence of acute oral toxicity or mutagenicity. The no-observed-adverse-effect level (NOAEL) was determined to be 2% in the diet, equivalent to 1410 mg/kg body weight/day in males and 1501 mg/kg body weight/day in females. Another study on Sprague-Dawley rats fed diets containing up to 2.5% GSE for three months also reported no treatment-related toxicological changes, supporting the safety of GSE at these levels.
Acute and Genotoxicity Tests
Acute oral toxicity tests determined that the lethal dose 50 (LD50) of GSE is higher than 5000 mg/kg. Genotoxicity tests, including the bacterial reverse mutation test and chromosomal aberration test, showed no significant mutagenic effects at tested doses. These findings suggest that GSE is not acutely toxic and has a low risk of genotoxicity.
Safe Dosage in Mice
A pilot study on albino mice assessed the safety of black and red GSE at doses of 200, 400, and 800 mg/kg body weight. The study found that doses of 200 and 400 mg/kg were safe, while the 800 mg/kg dose led to reduced body weight gain and organ changes. This indicates that lower doses of GSE are safe, but higher doses may pose risks.
Conclusion
The collective findings from various studies indicate that grape seed extract is generally safe for consumption at specified doses. Both animal and human studies support the safety of GSE, with no significant toxicological effects observed at typical consumption levels. However, higher doses may lead to minor adverse effects, such as temporary changes in serum iron levels. Further research with larger sample sizes and longer durations is recommended to confirm these findings and establish comprehensive safety guidelines.
Sources and full results
Most relevant research papers on this topic
90-day oral toxicity study of a grape seed extract (IH636) in rats.
Safety assessment of 4-week oral intake of proanthocyanidin-rich grape seed extract in healthy subjects.
Safety evaluation of proanthocyanidin-rich extract from grape seeds.
Blessings in disguise: Bio-functional benefits of grape seed extracts
Toxicology evaluation of a procyanidin-rich extract from grape skins and seeds.
Green tea and grape seed extracts — Potential applications in food safety and quality
Grape seed extract: having a potential health benefits
Subchronic 3-month oral toxicity study of grape seed and grape skin extracts.
Clinical and Histopathological study of black and red grape seed extracts (Vitis Vinifera) effects on the Albino Mice
Inhibitory effects of grape seed extract on lipases.
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