Grape seed extract, a health supplement derived from grape seeds (also available as grape seed oil), has demonstrated anti-cancer, anti-inflammatory, anti-microbial, and heart-protecting features, (R) and has powerful antioxidant functions. (R1, R2)
It’s a potent source of polyphenols, including resveratrol, quercetin, flavanals, flavanols, and anthocyanins, that explain much of its health-promoting activity. (R1,R2)
The extraordinary amount of antioxidant action GSE produces may be owed to the synergistic action of all of these compounds; (R) in other words, the whole is greater than the sum of its parts.
There is some evidence that grape seed extract is safe for human use even in significant doses. (R)
Table of Contents
The grape seed extract I use
NOW Grape Seed Extract (Amazon)
GSE’s antioxidant power
Just five days of supplementation with grape seed extract increased antioxidant activity in the blood of volunteers. (R)
In a placebo-controlled study of 40 female volleyball players, GSE treatment increased levels of the body’s master antioxidant, glutathione, and reduced levels of malondialdehyde (MDA), a key marker of oxidative stress. (R)
Two of grape seed extract’s many compounds, quercetin and gallic acid, demonstrated higher antioxidant activity than both synthetic antioxidants and those which the body normally uses, such as glutathione and alpha-tocopherol (a form of vitamin E). (R)
GSE protected animals from suffering liver damage by normalizing oxidant/anti-oxidant status, partially through preventing oxidation of lipids (fat). (R)
GSE all but eliminated the side effects of the severely liver-toxic chemotherapy drug methotrexate (MTX) in animals, partially through normalizing MDA. (R)
GSE protected against chemical-induced brain damage through prevention of programmed cell death (apoptosis) and antioxidant activity. (R)
GSE guarded against age-related DNA damage in several regions of the brain, including the cerebral cortex, striatum, and hippocampus, in animals. (R)
GSE resolved many of the issues associated with insufficient oxygen (hypoxia), including reductions in reactive oxygen species (ROS) and nitric oxide, thus demonstrating its value as an antioxidant. (R)
In animals forced to exercise, GSE treatment inhibited oxidative stress by prevention of oxidation of fats and increasing antioxidant enzyme activity. (R)
GSE reduces blood pressure
In a study of people with metabolic syndrome, GSE treatment lowered both systolic and diastolic blood pressure compared to placebo. (R)
In a review of 16 trials involving over 800 human participants, GSE was found to cause small but significant decreases in systolic and diastolic blood pressure. These benefits were more pronounced in younger subjects, the obese, and those with metabolic syndrome. (R)
A two-month trial with 90 menopausal women found that GSE treatment lowered systolic and diastolic blood pressure. In addition, GSE reduced menopausal symptoms, insomnia, depression, and anxiety, and increased muscle mass in the women. (R)
GSE protects the heart
A combination of GSE and the mineral chromium lowered cholesterol in high-cholesterol subjects by 16%, with almost all the reduction coming from LDL cholesterol. This combination, as well as GSE treatment alone, also dampened the autoimmune response to oxidized LDL cholesterol in the body. (R)
GSE protects against heart disease and heart attack by regulating expression and release of two forms of nitric oxide (R) among several forms of reactive oxygen species it scavenges, and by chelating iron (i.e., causing it to be excreted from the body). (R)
GSE relaxes blood vessels by increasing expression of eNOS, one form of nitric oxide. (R1, R2)
A placebo-controlled study of older obese diabetics found that GSE improved markers of inflammation and oxidative stress among subjects at high risk of corony events, leading researchers to conclude that it may reduce cardiovascular risk. (R)
In a study of 36 men and women with elevated risk of vascular disease, 2gms/day of grape seed extract improved flow-mediated dilatation (FMD), an important marker associated with increased risk of heart disease and cardiac events when low. (R)
In animals, GSE decreased levels of an enzyme elevated in heart disease (myeloperoxidase) in the large intestine. (R)
GSE improves blood sugar
Grape seed extract lowered blood glucose and insulin by a significant amount when added to animal feed. (R1, R2)
Taking GSE with a high-carbohydrate meal lowered participants’ blood sugar levels by an average of over five points. (R)
In female volleyball players, grape seed extract significantly increased insulin sensitivity and lowered levels of insulin in blood. (R)
GSE fights fat
Grape seed extract inhibits key enzymes associated with absorption of dietary fat and buildup of fatty tissue, and could theoretically reduce the load of free fatty acids in the bloodstream associated with insulin resistance in the obese. (R)
GSE treatment reduced daily caloric intake by 4% in people with high caloric requirements, leading researchers to theorize that it could assist with weight loss in those who are overweight and not controlling their diet already. (R)
Overweight and obese women who added grape seed oil to their diet saw a reduction in both a marker of inflammation, hs-CRP, as well as their degree of insulin resistance. (R)
An animal study on the effects of a high-fat diet found that GSE treatment resolved all problems associated with the diet; researchers concluded that grape seed extract appears to be “a safe anti-obesity and cardioprotective agent that should also find potential applications in other inflammatory damaging conditions [such] as stroke.” (R)
In subjects with non-alcoholic fatty liver disease (NAFLD), three months of GSE treatment reduced fat accumulation in the liver and a marker of liver damage when compared to those taking vitamin C. (R)
GSE is antibacterical
Grape seed extract showed bacteria-killing activity in all 43(!) strains of MRSA tested and did so via destruction of the bacterium’s cell wall. (R)
GSE has been found effective against dozens of varities of both gram-negative and gram-positive bacteria, with the same basic process: rapid destruction of the bacterial cell wall. (R1, R2)
GSE is antiviral
Grape seed extract proved to be strongly antiviral against four enteric (intestinal) viruses, including hepatitis A, (R), as well as human norovirus, feline callcivirus, and murine norovirus. (R)
GSE demonstrated activity against HIV-1 (R), the form of the virus most common outside West Africa. (R)
GSE boosted antibodies to an antiviral vaccine in animals, indicating the vaccine became more effective as a result. (R)
Flavonoids in grape seed extract induced antiviral and anticancer activity by elevating production of the cytokine (immune-signaling protein) gamma interferon, or IFN-γ. (R)
GSE and cancer
An exhaustive review concluded that grapes and grape products contain significant amounts of anticancer agents, with benefits noted for fighting skin, breast, colorectal and lung cancers, as well as gastric adenocarcinoma. (R)
A study of over 35,000 men between the ages of 50 and 76 found that the use of any grape seed supplement was associated with 41% reduced risk of prostate cancer. (R)
Grape seed extract and a chemotherapy drug, doxorubicin, demonstrated synergistic activity when used together against breast cancer cells. (R)
GSE boosted the effectiveness of one chemotherapy drug against colon cancer cells. (R)
GSE induced oxidative stress that triggered programmed cell death in bladder cancer cells. (R)
GSE protected animal livers from much of the harm induced by radiation. (R)
GSE proved useful in ameliorating the gastrointestinal damage associated with a chemotherapy-induced condition known as mucositis. (R)
Additional benefits
Grape seed extract makes sunscreen more effective, and may be a suitable replacement for ingredients with unknown toxicity. (R)
In animals, GSE reduced inflammatory bowel disease markers and associated inflammation, increased count of goblet cells (involved in the production of mucus), and increased counts of beneficial bacterial species in the large intestine. (R)
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