PJ Online | Grape seed extract (Dietary supplements)

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Pharmaceutical Journal
Vol 267 No 7178 p792
1 December 2001

Dietary supplements summary

(1) Grape seed extract

Description An extract from the seeds of Vitis vinifera. The main active ingredients are proanthocyanidins, which are derived from flavan-3-ols, a category of flavonoids. Grape seed proanthocyanidins are available in supplements with typical doses of 50–100mg.
Action Grape seed proanthocyanidins have antioxidant activity. They may also have anti-carcinogenic, anti-atherogenic and anti-inflammatory activity and may inhibit platelet aggregation. Proanthocyanidins are also claimed to inhibit the destruction of collagen, allowing red blood cells to cross the capillaries and prevent fluid exudation.

Reported uses Grapeseed extract supplements are promoted as antioxidants for circulatory disorders, such as varicose veins and intermittent claudication. They have been claimed to be useful for the treatment of allergies and asthma and for the prevention of cancer and myocardial infarction. However, studies with this substance tend to have been conducted in vitro or in animals and/or to be small and poorly controlled. There are insufficient clinical data to support the use of this supplement for any indication, although anecdotal reports suggest it to be beneficial in a variety of conditions.

Adverse effects None known.

Precautions Hypersensitivity to grapeseed extract. Pregnant and breast-feeding women should avoid grapeseed extract supplements pending long-term safety studies. Use with caution in people with a history of bleeding or haemostatic disorders.

Interactions Theoretically, grapeseed extract may enhance the effect of drugs affecting coagulation or platelet aggregation (eg, aspirin, warfarin, clopidogrel).

Many people who visit pharmacies want to buy or are already taking some form of dietary supplement. This series includes supplements either that are commonly sold in pharmacies and those which have attracted recent media interest, possibly resulting in the public wanting further information about them.

Each monograph covers the actions, possible uses, adverse effects, precautions and interactions, and is intended to be an aide-memoire for pharmacists advising their customers and patients. However, it should be emphasised that these monographs are summaries only, and readers who want more in-depth information, particularly details of research studies providing evidence on the use of these supplements, should consult other texts.

The series is written by Dr Pamela Mason (a pharmacist with a postgraduate qualification in nutrition)