What is Grapeseed Extract?
Grape seed extract (GSE) is a dietary supplement made from the seeds of grapes (Vitis vinifera), which are often by-products of the winemaking industry [1.2.3, 1.3.2]. It is a concentrated source of beneficial plant compounds called polyphenols, particularly proanthocyanidins [1.2.1, 1.3.7]. These compounds are powerful antioxidants that help protect the body's cells from damage caused by free radicals [1.3.7]. Due to its antioxidant activity, GSE has been studied for various potential health benefits, including supporting cardiovascular health and improving circulation [1.2.1, 1.3.7]. However, its medicinal use is not approved by the FDA, and there is insufficient evidence to support many health claims [1.2.1, 1.2.3]. While many people tolerate it well, it's crucial to understand who should not take grapeseed extract.
Individuals with Bleeding Disorders or on Blood-Thinning Medications
One of the most significant contraindications for grapeseed extract involves its effect on blood clotting. GSE may slow blood clotting and have a blood-thinning effect [1.2.7, 1.5.5]. This property means it can increase the risk of bleeding and bruising [1.5.4]. Therefore, individuals with existing bleeding disorders should avoid this supplement [1.2.2, 1.3.3].
Furthermore, people taking anticoagulant or antiplatelet drugs (blood thinners) must exercise caution. Combining GSE with these medications could amplify their effects, leading to an increased risk of bleeding [1.3.3, 1.5.5]. Medications of concern include:
- Warfarin (Coumadin, Jantoven) [1.2.2, 1.5.1]
- Clopidogrel (Plavix) [1.5.5]
- Aspirin [1.2.2, 1.5.5]
- NSAID painkillers like ibuprofen (Advil) and naproxen (Aleve) [1.3.3]
Individuals Scheduled for Surgery
Due to its potential to increase bleeding risk, individuals scheduled for surgery should avoid taking grapeseed extract [1.3.6]. It is recommended to discontinue use before a scheduled surgery to prevent excessive bleeding during and after the procedure [1.6.4]. Always inform your doctor about any supplements, including GSE, that you are taking before any medical procedure [1.3.4].
Pregnant and Breastfeeding Women
There is a lack of sufficient safety data on the effects of grapeseed extract in pregnant or breastfeeding women [1.7.1, 1.7.2, 1.7.5]. Animal studies have suggested that ingesting grape seed procyanidin extract during pregnancy could have negative effects on offspring, such as insulin resistance [1.7.6]. Given the unknown risks, health authorities recommend that women who are pregnant, planning to become pregnant, or breastfeeding should not use this supplement [1.2.3, 1.7.3, 1.7.7].
People with Certain Allergies
Individuals with a known allergy to grapes or grape products should not use grapeseed extract to avoid allergic reactions [1.2.3, 1.3.3]. Symptoms of an allergic reaction can be severe and may include hives, difficulty breathing, and swelling of the face, lips, tongue, or throat [1.3.2]. Additionally, some GSE formulations may contain other allergens, such as peanut skin extract, so reading labels carefully is essential for those with other allergies [1.3.6].
Potential for Drug Interactions
Grapeseed extract can interact with various medications because it may affect how the liver breaks them down [1.5.4]. Specifically, it can interact with drugs metabolized by a group of enzymes called Cytochrome P450 (including CYP3A4, CYP1A2, CYP2D6, and CYP2E1) [1.5.1, 1.5.4]. This interaction could change the effects and side effects of these medications [1.5.4].
Medications that may interact with GSE include:
- Certain heart and blood pressure medicines [1.3.3, 1.5.2]
- Some antidepressants and anti-anxiety drugs [1.5.2, 1.5.6]
- Cancer treatments [1.3.3]
- Muscle relaxants and pain medications [1.5.6]
Additionally, taking GSE with Vitamin C may raise blood pressure in individuals who already have hypertension [1.3.2]. Always consult with a healthcare provider before starting GSE if you are taking any regular medications [1.3.3].
Comparison of Precautions: Grapeseed Extract vs. Vitamin E
| Precaution | Grapeseed Extract (GSE) | Vitamin E |
|---|---|---|
| Bleeding Risk | High. May slow blood clotting and interacts with blood thinners [1.3.3, 1.5.5]. | High doses can increase bleeding risk, especially when taken with blood thinners. |
| Surgery | Discontinue use before surgery due to bleeding risk [1.6.4]. | Discontinue use before surgery due to bleeding risk. |
| Pregnancy | Not recommended due to lack of safety data and potential harm [1.7.3, 1.7.6]. | Generally considered safe in recommended dietary amounts, but high-dose supplements should be avoided. |
| Drug Interactions | Interacts with blood thinners, NSAIDs, and medications metabolized by the liver (Cytochrome P450 enzymes) [1.3.3, 1.5.4]. | Interacts with blood thinners, chemotherapy drugs, and statins. |
| Allergies | Avoid if allergic to grapes [1.3.3]. | Generally well-tolerated, though rare allergic reactions can occur. |
Conclusion
While grapeseed extract is a popular supplement with potential antioxidant benefits, it is not suitable for everyone. Individuals with bleeding disorders, those taking blood-thinning medications, people preparing for surgery, and women who are pregnant or breastfeeding should avoid its use [1.2.2, 1.3.6, 1.7.1]. Furthermore, anyone with a grape allergy or those taking medications metabolized by the liver should consult a healthcare professional before taking GSE [1.3.3, 1.5.1]. As with any supplement, it is crucial to discuss its use with a doctor to ensure it is safe and appropriate for your individual health circumstances.
For more authoritative information on dietary supplements, you can visit the National Center for Complementary and Integrative Health (NCCIH).
