The Allure and Ambiguity of Ginkgo Biloba
Ginkgo biloba, often called a "living fossil," is one of the oldest tree species and a staple in traditional Chinese medicine for centuries. Today, its extract is one of the most popular herbal supplements worldwide, taken for a range of purported benefits, most famously for improving memory and cognitive function. However, the scientific evidence supporting its effectiveness is often contradictory and inconclusive. While many studies suggest modest benefits for conditions like dementia, anxiety, and peripheral artery disease, others find no significant effect. This ambiguity, combined with its widespread use, makes it crucial to ask: is there a downside to Ginkgo biloba?
Common and Mild Side Effects
Though ginkgo leaf extract is generally well-tolerated by most healthy adults, it is not without potential side effects. These reactions are typically mild and can include:
- Headache
- Dizziness
- Upset stomach or nausea
- Diarrhea or constipation
- Heart palpitations
- Allergic skin reactions, such as a rash
It is essential to distinguish between the processed ginkgo leaf extract used in supplements and other parts of the plant. Raw or roasted ginkgo seeds are toxic and should never be consumed. Eating as few as 10 roasted seeds can cause serious side effects like seizures, and fresh seeds can be lethal.
Serious Risks and Major Concerns
Beyond mild discomforts, Ginkgo biloba presents more significant risks, primarily centered around its effect on blood clotting.
Increased Risk of Bleeding Ginkgo has antiplatelet properties, meaning it can slow blood clotting. This poses a significant danger for certain individuals and situations:
- Bleeding Disorders: People with existing bleeding disorders should not use ginkgo as it can worsen their condition.
- Surgery: It is recommended to stop taking ginkgo at least two weeks before any scheduled surgery or dental procedure to prevent excessive bleeding.
- Drug Interactions: The risk of bleeding is amplified when ginkgo is taken with other substances that also thin the blood. This includes common over-the-counter NSAIDs like ibuprofen and aspirin, as well as prescription anticoagulants like warfarin.
Seizures In some cases, ginkgo has been linked to an increased risk of seizures. This is particularly concerning for individuals with epilepsy or a history of seizures, who are advised to avoid the supplement altogether. This risk may also be heightened when taken with other medications or supplements that lower the seizure threshold. Overdosing on ginkgo can also lead to seizures.
Critical Drug Interactions
Ginkgo biloba can interact with over 290 drugs, with most interactions being moderately clinically significant. It can alter how the liver breaks down certain medications, potentially reducing their effectiveness or increasing side effects. Anyone taking prescription medication should consult a healthcare provider before starting ginkgo.
Key interactions include:
- Blood Thinners (e.g., Warfarin, Aspirin, Ibuprofen): Increases risk of bleeding.
- Antidepressants (e.g., Prozac, Trazodone): May decrease the effectiveness of some antidepressants or, in the case of trazodone, lead to serious side effects like a coma.
- Anti-seizure Medications: Ginkgo may reduce the effectiveness of these drugs, increasing the risk of seizures.
- Diabetes Medications: The supplement can interfere with blood sugar management.
- Anxiety Medications (e.g., Xanax): Ginkgo might reduce the medication's effectiveness.
- Statins (e.g., Lipitor, Zocor): Ginkgo may reduce the effectiveness of these cholesterol-lowering drugs.
Ginkgo's Effects: Purported Benefits vs. Potential Risks
| Feature | Purported Benefits | Potential Downsides |
|---|---|---|
| Cognitive Function | Some studies suggest modest improvement in symptoms of dementia and cognitive function. | Major studies show it does not prevent dementia or significantly improve memory in healthy adults. |
| Circulation | May improve blood flow, potentially benefiting conditions like claudication (leg pain from poor circulation) and glaucoma. | Increases the risk of serious bleeding, especially when combined with blood thinners like aspirin or warfarin. |
| Mental Health | Limited research suggests it may help reduce symptoms of anxiety and depression, particularly as an adjunct therapy. | Can interfere with the effectiveness of antidepressants and anxiety medications like Xanax. |
| Safety | Generally considered safe for most healthy adults in standardized extract form. | Raw seeds are poisonous. Leaf extract is contraindicated for pregnant women, people with bleeding disorders, or epilepsy. |
| Drug Interactions | Interacts with hundreds of medications, including common pain relievers (ibuprofen), statins, and diabetes drugs. |
Conclusion: A Calculated Decision
So, is there a downside to Ginkgo biloba? The answer is a definitive yes. While millions use it without issue, the potential for side effects, serious bleeding risks, and extensive drug interactions cannot be ignored. The evidence for its benefits remains inconsistent, while the risks, though not universal, are well-documented. It is not a supplement to be taken lightly. Individuals who are pregnant, have bleeding disorders, epilepsy, or diabetes should avoid it. Given its potential to interact with more than 290 medications, consulting with a healthcare professional before adding Ginkgo biloba to your regimen is not just a recommendation—it is an essential safety measure.
For more information from an authoritative source, consider visiting the National Center for Complementary and Integrative Health (NCCIH) page on Ginkgo: https://www.nccih.nih.gov/health/ginkgo
