Grapes are one of the most consumed fruits in the entire world. In ancient Europe, the leaves and sap of grape plants have been used for traditional treatment for centuries. But what are the benefits of grape seed extract?
Besides the fact that grapes are a source of vitamins and fiber, grape seeds contain many important nutrients such as polyphenolic compounds, the main among which can be considered proanthocyanidins.
Proanthocyanidins can be used as a functional ingredient to address a variety of health problems by stimulating the body’s natural bioprocesses.
What Are the Benefits of Grape Seed Extract?
Scientific publications report that grape seed polyphenols have many beneficial and even medicinal properties, such as:
- mitigation of cell carcinogenesis in breast tissues ,
- modulation of blood pressure in persons with prehypertension ,
- maintaining glucose homeostasis in diabetes ,
- protection against ischemic injuries ,
- promoting the healing of skin wounds ,
- protection against diabetic nephropathy .
Grape seed polyphenols (like most other polyphenolic compounds) are powerful antioxidants. Indeed, the health benefits of polyphenolic compounds, including grape seed proanthocyanidins, have traditionally been attributed to their antioxidant activity .
Antioxidant activity may be the main factor contributing to the role of grape seed polyphenols in protection against breast cancer , wound healing , and ischemic injury .
However, the polyphenols found in grape seeds have the potential to induce additional beneficial disease-modifying mechanisms. For example, grape seed polyphenols have the ability to mitigate diabetic nephropathy through mechanisms including decreased expression of advanced glycation end products and connective tissue growth factor in the kidney .
As another example, grape seed polyphenols contribute to the maintenance of glucose homeostasis in diabetes, in particular, by activating insulin receptor signaling pathways .
Recent observations from experimental in vitro [9, 10] and preclinical studies  have shown that grape seed polyphenols may influence specific neuropathogenic mechanisms underlying Alzheimer’s disease, and suggest a potential new role for grape seed polyphenols for its treatment.
Other Benefits of Grape Seed Extract, Based on Science
So, what is grape seed extract good for?
Glycemic Control, Serum Lipoproteins, Inflammation, and Body Weight
Just this year, a corresponding systematic review of experimental data and a meta-analysis was published. The aim of it was to analyze the effect of grape seed extract (EVA) on glycemic control and serum lipoproteins, inflammation, and body weight .
This meta-analysis included 50 studies. The research results showed a significant decrease in fasting plasma glucose (-2.01), total cholesterol (-6.03), low-density lipoprotein (LDL) (-4.97), triglycerides (-6.55) and C- reactive protein (CRP) (-0.81) after GSE therapy.
Grape seed extract did not affect the level of glycated hemoglobin (HbA1c), HDL cholesterol levels, and anthropometric parameters.
An earlier review examined the effect of grape seed extract therapy on systolic/diastolic blood pressure (SBP / DBP) fluctuations.
Available randomized controlled trials were used for meta-analysis .
12 publications were analyzed, including a study of 810 subjects in 16 clinical trials. The general analysis revealed a significant decrease in SBP (-6.077) and DBP (-2.803) as a result of therapy with grape seed extract.
If we analyze the data of subgroups, it turns out that in younger subjects (mean age <50 years), a sustained decrease in SBP (-6.049) and DBP (-3.116) could be observed, even in patients with metabolic syndrome (-8.487).
A meta-regression analysis performed further revealed that indicators such as age, body weight index, and baseline blood pressure were negatively associated with a marked decrease in SBP and DBP in the period following treatment.
The decrease in blood pressure was more pronounced in longitudinal studies (over 8 weeks).
There was no evidence of any bias in the published studies.
These results demonstrated that grape seed extract had a positive effect on blood pressure values, and this effect was much more pronounced in young or obese people, as well as in patients with metabolic disorders.
Given the relatively small sample size, the authors agreed that it would be quite justified to confirm the results of studies in a large-scale, long-term, repeated randomized controlled trial, including necessarily among patients with arterial hypertension.
Protection Against Oxidative Stress and Tissue Damage
Free radicals are implicated in more than a hundred diseases in humans, including:
- hemorrhagic shock,
- progressive age,
- ischemia and reperfusion injury to multiple organs,
- Alzheimer’s and Parkinson’s disease,
- gastrointestinal dysfunction,
- tumor development and carcinogenesis,
Antioxidants are powerful free radical scavengers and inhibitors of tumor processes. A large number of synthetic and natural antioxidants have been shown to have beneficial effects on human health and disease prevention.
However, the structure-activity ratio, bioavailability, and therapeutic efficacy of antioxidants vary greatly.
The concentration- or dose-dependent ability to protect against free radicals of the proanthocyanidin-rich grape seed extract was evaluated.
In particular, in vitro and in vivo conditions, its antioxidant function was compared with vitamins C, E, and beta-carotene.
Experiments have shown that grape seed extract is highly bioavailable and provides significantly greater protection against free radicals and free radical-induced lipid peroxidation and DNA damage than vitamins C, E, and beta-carotene.
It has also been shown that grape seed extract exhibits cytotoxicity against human breast, lung, and stomach adenocarcinoma cells while increasing the growth and viability of normal cells of the human gastric mucosa.
Comparative protective effects of grape seed extract, vitamins C and E on tobacco-induced oxidative stress and apoptotic cell death in human oral keratinocytes were studied.
Oxidative tissue damage was determined by lipid peroxidation and DNA fragmentation, and apoptotic cell death was assessed by flow cytometry.
The extract of grape seed provided significantly better protection compared to vitamins C and E, either alone or in combination.
The extract has also shown excellent protection against acetaminophen overdose-induced liver and kidney damage by regulating the bcl-X (L) gene, DNA damage, and presumably reducing oxidative stress.
Grape seed extract has shown excellent protection against myocardial ischemia-reperfusion injury and myocardial infarction in rats.
It has also been shown that the extract of grape seed upregulates the bcl (2) gene and lowers the c-myc oncogene.
The topical application of grape seed extract enhances the sun protection factor in human volunteers and has also improved the course of chronic pancreatitis in human studies.
These results demonstrate that grape seed extract provides superior protection against oxidative stress and tissue damage mediated by free radicals .
Dosage of Grape Seed Extract
So, how much grape seed extract to take?
The use of the extract is well tolerated and safe, at least at experimental doses up to 2500 mg/day .
The dosage depends on the content of active ingredients in the extract. Thus, an extract containing predominantly proanthocyanidin (this information is indicated on the package) is effective in a dosage of 100-400 mg per day, and containing mainly polyphenols 800-2000 mg per day.
To feel all the benefits of grape seed extract, you can take it once a day or divide the daily dose into two doses, regardless of food intake.
- Grape seed proanthocyanidin suppression of breast cell carcinogenesis induced by chronic exposure to combined 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone and benzo[a]pyrene. Song X, Siriwardhana N, Rathore K, Lin D, Wang HC.Mol Carcinog. 2010 May; 49(5):450-63.
- Effect of grape seed extract on blood pressure in subjects with the metabolic syndrome. Sivaprakasapillai B, Edirisinghe I, Randolph J, Steinberg F, Kappagoda T Metabolism. 2009 Dec; 58(12):1743-6
- Oligomers of grape-seed procyanidin extract activate the insulin receptor and key targets of the insulin signaling pathway differently from insulin. Montagut G, Onnockx S, Vaqué M, Bladé C, Blay M, Fernández-Larrea J, Pujadas G, Salvadó MJ, Arola L, Pirson I, Ardévol A, Pinent M J Nutr Biochem. 2010 Jun; 21(6):476-81.
- Protective effect of grape seed extract against ischaemia/reperfusion injury in a rat epigastricflap model. Karaaslan O, Ulusoy MG, Kankaya Y, Tiftikcioglu YO, Kocer U, Kankaya D, Karaaslan GM, Tuncer S, Berktas M J Plast Reconstr Aesthet Surg. 2010 Apr; 63(4):705-10.
- Dermal wound healing properties of redox-active grape seed proanthocyanidins. Khanna S, Venojarvi M, Roy S, Sharma N, Trikha P, Bagchi D, Bagchi M, Sen CK Free Radic Biol Med. 2002 Oct 15; 33(8):1089-96
- Grape seed proanthocyanidins ameliorate diabetic nephropathy via modulation of levels of AGE, RAGE and CTGF. Li X, Xiao Y, Gao H, Li B, Xu L, Cheng M, Jiang B, Ma Y Nephron Exp Nephrol. 2009; 111(2):e31-41.
- Free radicals and grape seed proanthocyanidin extract: importance in human health and disease prevention. Bagchi D, Bagchi M, Stohs SJ, Das DK, Ray SD, Kuszynski CA, Joshi SS, Pruess HG. Toxicology. 2000 Aug 7; 148(2-3):187-97.
- Effects of a grapeseed procyanidin extract (GSPE) on insulin resistance. Montagut G, Bladé C, Blay M, Fernández-Larrea J, Pujadas G, Salvadó MJ, Arola L, Pinent M, Ardévol A J Nutr Biochem. 2010 Oct; 21(10):961-7.
- Grape seed polyphenolic extract as a potential novel therapeutic agent in tauopathies. Ho L, Yemul S, Wang J, Pasinetti GM. J Alzheimers Dis. 2009; 16(2):433-9.
- Grape-derived polyphenolics prevent Abeta oligomerization and attenuate cognitive deterioration in a mouse model of Alzheimer’s disease. Wang J, Ho L, Zhao W, Ono K, Rosensweig C, Chen L, Humala N, Teplow DB, Pasinetti GM. J Neurosci. 2008 Jun 18; 28(25):6388-92
- Consumption of grape seed extract prevents amyloid-beta deposition and attenuates inflammation in brain of an Alzheimer’s disease mouse. Wang YJ, Thomas P, Zhong JH, Bi FF, Kosaraju S, Pollard A, Fenech M, Zhou XF. Neurotox Res. 2009 Jan; 15(1):3-14.
- The effects of grape seed extract on glycemic control, serum lipoproteins, inflammation, and body weight: A systematic review and meta-analysis of randomized controlled trials Omid Asbaghi, Behzad Nazarian, Željko Reiner, Elaheh Amirani, Fariba Kolahdooz, Maryam Chamani, Zatollah Asemi.Phytother Res. 2020 Feb;34(2):239-253.
- The impact of grape seed extract treatment on blood pressure changes: A meta-analysis of 16 randomized controlled trials Haili Zhang, Shuang Liu, Lan Li, Shisong Liu, Shuqi Liu, Jia Mi, Geng Tian. Medicine (Baltimore). 2016 Aug;95(33):e4247.
- Free radicals and grape seed proanthocyanidin extract: importance in human health and disease prevention D Bagchi , M Bagchi, S J Stohs, D K Das, S D Ray, C A Kuszynski, S S Joshi, H G Pruess. Toxicology . 2000 Aug 7;148(2-3):187-97.
- Safety assessment of 4-week oral intake of proanthocyanidin-rich grape seed extract in healthy subjects Atsushi Sano. Food Chem Toxicol . 2017 Oct;108(Pt B):519-523.
More about this topic: