What are the benefits of grape seed extract?

By Joseph Nordqvist

Medical News Today

Reviewed by Karen Cross, FNP, MSN

Grape seed extract is an industrial derivative of grape seeds. It is rich in antioxidants and oligomeric proanthocyanidin complexes and has been linked to a wide range of possible health benefits.

These include the treatment of conditions such as high cholesterol, atherosclerosis, macular degeneration, poor circulation, and nerve damage.

Many of these health claims are still not completely backed by high-quality studies, but some evidence supports its use.

Grape seed extract is available as a dietary supplement in a liquid form, tablets, or capsules. Supplements commonly contain between 50 and 100 milligrams (mg) 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

• Some evidence shows that grape seed extract might aid wound healing.
• Grape seed extract should be avoided during pregnancy.
• Some researchers believe that the proanthocyanidins it contains hold a range of benefits.

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 chemo-preventive 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.

Healing wounds

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 proanthocyanidin 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

Including grape seed extract in your diet with calcium has a "beneficial effect on bone formation and bone strength for the treatment of bone debility caused by a low level of calcium."

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.

Anti-Candida activity

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 flavanols. 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 flavanols 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. 

Cardiovascular benefits

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."

The National Center for Complementary and Integrative Health (NCCIH) note that it may help reduce systolic blood pressure and heart rate, but they point out that it will not help decrease lipid levels, for example, cholesterol, in the blood.

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."

The NCCIH is supporting studies on the effect of grape seed extract on Alzheimer's disease.

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)
• reducing edema
• relieving symptoms of chronic venous insufficiency
• reducing iron levels in people with hemochromatosis
• reducing inflammation

Estrogen plays a substantial role in breast cancer. 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.

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.

Grape seed extract might also act as an anticoagulant, or blood-thinner. It could increase the risk of bleeding if taken with other blood-thinners such as warfarin (Coumadin), clopidogrel (Plavix), or aspirin.

The NCCIH describes grape seed extract as "generally well tolerated when taken in moderate amounts."

It is available for purchase online at https://luxxe.us