Grape seed extract is an industrial derivative of grape seeds, extremely rich in antioxidants and oligomeric proanthocyanidin complexes. The extract has been linked to a wide range of possible therapeutic properties.
Its benefits may help in the treatment of conditions such as high cholesterol, atherosclerosis, macular degeneration, poor circulation, and nerve damage.
Although many of these health claims are still not completely backed by high-quality studies, evidence is beginning to emerge on grape seed extract's extensive health benefits.
Grape seed extract is available as a dietary supplement in a liquid form, tablets, or capsules. Supplements commonly contain between 50 and 100 milligrams of the extract.
This article provides details on the benefits of grape seed extract as well as side effects and precautions associated with its use.
Fast facts on grape seed extract
Here are some key points about grape seed extract. More detail and supporting information is in the main article.
- Some evidence shows that grape seed extract might aid wound healing
- Pregnant women should avoid taking grape seed extract
- Some researchers believe that the proanthocyanidins it contains hold a range of benefits
Health benefits of grape seed extract
Grape seed extract contains proanthocyanidins
Studies on animal models have revealed that grape seed extract can be effective in treating heart disease.
Some experts think that grape seed extract could even have anticancer and cancer chemopreventive potential.
Over recent years, there has been a great deal of research pointing to possible therapeutic properties of grape seed extract. Listed below are some of the key findings.
Grape seed extract has the potential to increase the speed that wounds heal. A study, published in the journal Free Radical Biology and Medicine, applied proanthycyanidin extract onto wounds on the backs of mice. They found that the mice treated with this solution had quicker healing times.
According to the researchers they "provided firm evidence to support that topical application of GSPE [Grape seed proanthocyanidin extract] represents a feasible and productive approach to support dermal wound healing."
Although it is not clear how this protection occurs, GSPE was found to increase production of vascular endothelial growth factor, a compound important in the wound healing process.
Improving bone strength
This is according to a study published in the Journal of Musculoskeletal & Neuronal Interactions that investigated the effects of calcium and proanthocyanidins on the bone structure of mice which had been fed a low-calcium diet.
A study conducted in Italy examined grape seed extract's ability to attack Candida, a yeast-like parasitic fungus that can, sometimes, cause thrush. Grape seed oil contains flavan-3-ols. The researchers concluded:
"The results pointed out a significant inhibition of Candida albicans load 5 days after challenge. These findings indicate that grape seed extracts with high content of polymeric flavan-3-ols can be used in mucosal infection such as vaginal candidiasis."
Preventing skin cancer
Grape seeds contain proanthocyanidins which might prevent the development of cancer. A study, published in the journal Molecular Nutrition & Food Research, found that grape seeds have properties that can reduce the severity of skin cancer.
Using hairless mice, the research team tested the ability of grape seed proanthocyanidins to slow the formation of skin tumor development.
The researchers concluded that grape seed extracts "could be useful in the attenuation of the adverse UV-induced health effects in human skin."
It is thought that the protective nature of proanthocyanidins comes via a number of routes including a reduction in oxidative stress and immunosuppression by altering cytokine activity. Further research is needed to firm up the findings.
The antioxidants in grape seed extract can potentially protect the blood vessels from becoming damaged, which may prevent high blood pressure.
According to one study, published in the journal Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis, "grape seed proanthocyanidin extract (GSPE) provides superior antioxidant efficacy as compared to Vitamins C, E, and β-carotene."
Preventing cognitive decline
Grape seed extract is very high in proanthocyanidins which some believe could prevent cognitive decline.
One study identified "a critical role for grape seed proanthocyanidin extract (GSPE) as a neuroprotectant in the hippocampus and in preventing cognitive loss with aging."
Other possible benefits associated with grape seed extract include:
- Treating tooth decay
- Protecting against pathogens
- Improving night vision
- Alzheimer's disease
- Treating diabetic retinopathy and improving blood sugar control
- Relieving symptoms of chronic venous insufficiency
- Anti-aging properties (protecting collagen and elastin)
Dubious effects on estrogen levels - estrogen plays a substantial role in breast cancer. Because of this, drugs designed to modulate estrogen and estrogen receptors are vital. Some animal studies inferred that grape seed extract might work to alter estrogen levels.
However, a study in 2014 showed that four daily doses of grape seed extract "did not significantly decrease estrogen or increase androgen precursors."
Preventing hair loss by consuming grape seed extract has been theorized. Some nutritionists believe that proanthocyanidins inhibit (dihydrotestosterone) DHT, one of the hormones thought to be involved in hair loss but, evidence for its effectiveness is scant.
Side effects and precautions
Common side effects include:
It is important to talk to your doctor before taking grape seed extract as it can affect the way that certain medications are broken down in the liver.
It is possible that grape seed extract might act as an anticoagulant. According to the University of Maryland Medical Center, "Grape seed extract may act as a blood-thinner, and could increase the risk of bleeding if taken with other blood-thinners such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin."
Unfortunately, according to the Journal of Health Science, grape seed oil does not contain the beneficial proanthocyanidins found in grape seed extract.
In addition, pregnant women should completely avoid taking grape seed extract supplements.