Meta-analysis supports grape seed extract’s cardiovascular potential

By Stephen Daniells

- Last updated on GMT

© Getty Images / Dimijana
© Getty Images / Dimijana

Related tags Grape seed extract Cholesterol levels

Extracts from the seeds of grapes may significantly improve cholesterol and triglyceride levels, and reduce markers of inflammation, according to a new meta-analysis of 15 randomized trials.

Data published in the journal Phytotherapy Research​ indicated that grape seed extract was associated with significant decreases in total and LDL cholesterol and triglycerides, while C‐reactive protein (CRP) levels were also significant reduced.

Supplementation was also associated with significant reductions in fasting plasma glucose (FPG), wrote researchers based in Iran, Croatia, and Canada.

“[I]t seems the beneficial effects of grape seed on TC and LDL cholesterol levels may be due to inhibiting intestinal cholesterol absorption,” ​they wrote. “However, it is most likely that the primary beneficial effect of grape seed occurs due to mechanisms other than just decrease of plasma lipoproteins concentrations, including scavenging of hydroxyl and peroxyl radicals, antioxidant activities, and suppressing of the oxidation of LDL.

“Therefore, it seems that the antioxidant properties of grape seed polyphenols are central to their mechanism(s) of action, which also include cellular signaling mechanisms and interactions at the genomic level.”

A widely used botanical extract

According to the ABC-AHP-NCNPR Botanical Adulterants Prevention Program​, grape seeds are a by-product of the wine and juice industry. Extracts are prepared by drying the seeds and then using a solvent to obtain a polyphenol-rich product.

“Due to the widespread history and acceptance of grapes and wine, GSE has received acceptance almost globally as an ingredient for human consumption. It is one of the more widely used botanical extracts, due to increasing scientific findings supporting health benefits,”​ states a Botanical Adulterants Bulletin on grape seed extract (Vitis vinifera​).

Meta-analysis details

For the new systematic review and meta‐analysis, the researchers performed a literature search of online databases, including EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science and identified 15 trials for inclusion in their analysis. The included studies used doses from 100 mg of a grape seed proanthocyanidin extract up to 2,000 mg per day. Study duration ranged from four to 25 weeks.

Pooling the data indicated that grape seed extract may significantly decrease concentrations of fasting plasma glucose, total cholesterol, LDL cholesterol, triglycerides, and C‐reactive protein (CRP).

“Our finding that GSE reduces CRP levels might be an interesting additional explanation why GSE could have antiatherogenic effects. It is in accordance with findings of some other authors who have suggested that grape seed has anti‐inflammatory effects,” ​wrote the researchers.

On the other hand, no effect on HbA1c or HDL cholesterol levels were observed.

Source: Phytotherapy Research
Published online ahead of print, doi: 10.1002/ptr.6518​  
“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”
Authors: O. Asbaghi, et al.

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