This plant extract comes from the gingko or maidenhair tree. This tree is commonly called a "living fossil" because it's been a feature of the earth's landscape since the time of the dinosaurs. Gingko trees' fossilized ancestors are commonly found in rocks from the Jurassic and Cretaceous periods. Gingko trees can grow all over the world but are most commonly found in China and Japan. The oldest known specimen was 3,500 years old. Traditional Chinese medicine has used them for thousands of years. Presently, gingko is available as tablets, capsules, teas, and fortified foods.
Don't use gingko seeds because they can be extremely toxic.
Active ingredients
The leaves of the gingko tree are believed to have medicinal properties and, when analyzed scientifically, have been found to contain two main groups of active chemicals:- Flavonoids have antioxidant properties and are thought to have most protective effect on brain cells.
- Terpenoids improve blood flow by dilating blood vessels and stopping platelets from sticking to each other to form blood clots within the body.
- Improving their cognitive functions, particularly memory
- Reducing their chance of developing mood changes, especially depression
- Improving their ability to carry out everyday tasks and to socialize with other people
Side effects
Gingko biloba's common potential side effects include nausea, upset stomach, dizziness, restlessness, and skin rashes. However there is another major side effect to consider: gingko biloba has blood-thinning properties and decreases the ability of the blood to clot. Stop using gingko before surgery or dental work. Don't use gingko if you're on prescription blood thinners because it increases bleeding risk.Gingko is also known to interact with a number of prescription medicines:
- Anticoagulants: The similar effects of gingko can magnify the effects of all medicines used to thin the blood if the treatments are taken together. People taking warfarin (Coumadin), aspirin, clopidogrel (Plavix), or the newer blood thinners (Pradaxa, Eliquis, Savaysa, or Xarelto), should avoid gingko.
- Anticonvulsants: The effectiveness of anticonvulsants, used to treat epilepsy, may be reduced by gingko, increasing the risk of seizures. Gingko decreases the effectiveness of carbamazepine (Tegretol) and valproic acid (Depakote), so don't take gingko if you're on these medications.
- Antidepressants: Selective serotonin reuptake inhibitors (SSRIs — a group that includes citalopram, sertraline, fluoxetine, and paroxetine) can interact with gingko and set off serotonin syndrome, the symptoms of which include high blood pressure, a racing heart, excessive sweating, a tremor, muscle rigidity, increased reflexes, anxiety, agitation, and potentially coma or death. Don't use gingko with SSRI antidepressants.
- Antihypertensives: Because it dilates the blood vessels, gingko can cause the blood pressure to drop for people already on medication to treat high blood pressure. This drop in blood pressure can be dangerous.
- Diabetes medications: Gingko can lower blood sugar levels so don't take it with insulin or other diabetes medications.
Evidence
Gingko is marketed as a dietary supplement. Gingko has been studied as a treatment for AD, vascular dementia, and mixed dementias. And although a 20-year study published in 2013 by a team from Bordeaux, France, found that gingko reduced expected cognitive decline in healthy older people, other researchers have found that it has no actual protective benefit in reducing the occurrence of dementia. Comparisons of the effects of gingko versus those of approved dementia medicines for AD such as rivastigmine have, however, not been so positive — the pharmaceutical came out on top. However, a 2009 study found that gingko's effectiveness for AD patients wasn't statistically different from donepezil.Some studies have found gingko to stabilize and even improve cognitive and social function of these demented patients for 6 months to a year. Other studies have shown gingko is equivalent to placebo in dementia treatment. Clearly, the jury is still out on gingko's benefit in dementia.
Gingko is thus by no means a miracle drug and no substitute for prescription medicines for dementia. However, for those dementia patients not taking any of the medicines that may interact negatively with it, gingko may have benefit.