Ginkgo Biloba: Health Benefits, Side Effects and Interactions
Ginkgo biloba is an herb made from the leaves of the ginkgo biloba tree, also known as the maidenhair tree, the oldest living tree species on earth, dating back 270 million years. This herb has been used in the traditional Chinese medicine for more than a thousand years to treat asthma, digestive disorders and various other diseases.
Today, ginkgo is used in complementary and alternative medicine for a number of ailments, including dementia, early stage Alzheimer’s disease as well as leg pain caused by clogged arteries called claudication. Currently, there is also ongoing scientific research regarding the herb’s effectiveness at treating numerous other conditions.
Types of Ginkgo Biloba
There are three types of ginkgo products, derived from the leaves or the seeds of the ginkgo biloba tree:
Ginkgo biloba leaf extract. This is the most common form of ginkgo used in most supplements. Leaf extract contains concentrated levels of phytochemicals.
Ginkgo leaves. Although dried leaves do not contain the same concentrations of plant chemicals as the leaf extract, they were used for centuries in the Chinese folk medicine (e.g. to brew tea), long before the modern extraction process was developed.
Ginkgo seeds. Traditional Chinese medicine has also used the ginkgo seeds for centuries, even for cooking. However, in rare cases toxic reactions caused by ginkgotoxins present in the seeds (but not the leaves) may lead to seizures and loss of consciousness following ingestion.
Potential Health Benefits of Ginkgo Biloba
Ginkgo leaves contain two types of phytochemicals, called terpenoids and flavonoids, which are the basis of its medicinal properties.
Terpenoids (terpenes) act as antioxidants, ridding the body of free radicals that circulate in the bloodstream and cause harm to the body’s cells and organs. Terpenoids also inhibit platelet-activating factor, an enzyme associated with inflammation and blood clotting. Furthermore, terpenoids called ginkgolides and bilobalides work together to improve blood flow and circulation, particularly in the brain.
Flavonoids (flavones) also have antioxidant properties and help strengthen blood vessel walls. They are found in many fruits, vegetables, seeds and nuts. Researchers believe that there are as many as 40 types of different flavonoids in ginkgo.
Conditions Treated with Ginkgo Biloba
In addition to being used for treating dementia, early stage Alzheimer’s disease and claudication, ginkgo is also believed to help with a number of other conditions. These include:
- Age-associated memory impairment
- Age-related macular degeneration
- Altitude sickness
- Cerebral insufficiency
- Chemotherapy side effects
- Decreased libido in men and women
- Depression and seasonal affective disorder
- Erectile dysfunction in men
- Malignant tumors of the upper digestive tract
- Memory enhancement in healthy people
- Multiple sclerosis
- Premenstrual syndrome
- Pulmonary interstitial fibrosis
- Ringing in the ears called tinnitus
Potential Adverse Effects of Ginkgo Biloba
Although ginkgo biloba is generally considered safe, there are certain conditions for which use of this herbal supplement is not advised. Therefore, before you start taking ginkgo consult your doctor to discuss the potential for interactions with medications and adverse reactions to existing medical conditions such as hemophilia, hypoglycemia or diabetes.
The most common side effects of ginkgo biloba use include dizziness, headache, nausea and minor gastrointestinal complaints. Additional potential risks associated with this herb include:
Bleeding. Taking ginkgo biloba may cause bleeding (e.g., nose bleeds, internal eye and intracranial bleeding) and also increased bleeding during surgical procedures. Patients with existing bleeding disorders or those taking medications or other herbal supplements that increase the risk of bleeding may further increase their risk of complications when taking ginkgo.
Glucose levels. Scientists warn that ginkgo may potentially affect insulin and blood sugar levels. Hence, to avoid potential complications patients with diabetes or hypoglycemia should consult their doctor prior to using ginkgo.
Allergic reactions/hypersensitivity. Like many other herbs ginko can also cause allergic reactions in sensitive people.
Pregnancy and breastfeeding. Ginkgo is not recommended for pregnant or breastfeeding women due to increasing the risk of bleeding during pregnancy and delivery and its adverse effects on developing fetuses.
Eating ginkgo seeds may in some individuals cause seizures, loss of consciousness and, in rare instances, death.
Ginkgo’s Interactions with Medications and Other Substances
The most commonly reported interaction of ginkgo biloba is with anticoagulant medications and aspirin, causing spontaneous bleeding. Antiplatelet drugs and nonsteroidal anti-inflammatory drugs taken with ginkgo have also been found to increase the risk of bleeding. Other possible drug interactions may include:
- Antidepressants such as monoamine oxidase inhibitors and selective serotonin reuptake inhibitors.
- Antipsychotic drugs
- Glucose-lowering drugs
- Sexual dysfunction drugs
Ginkgo may also cause potentially serious interactions, such as increased risk of bleeding, when combined with certain herbs and dietary supplements, including saw palmetto, garlic, ginseng, black cohosh, ginger, green tea and vitamin E. In addition, garlic, eucalyptus oil, goldenseal and turmeric may interact with ginkgo to lower blood pressure while ginger, ginseng, licorice and cayenne may increase blood pressure. Some foods containing tyramine, such as cheese, yogurt, processed meats, bean curd and wine, may also interact with ginkgo, leading to increased blood pressure.
Where to Find More Information: University of Maryland Medical Center