No Evidence That Ginkgo Biloba Benefits Cognition

A recent study, Ginkgo Evaluation of Memory (GEM), by Beth E. Snitz, Ph.D., of the University of Pittsburgh, demonstrates that the use of the herbal supplement Ginkgo biloba does not slow the rate of cognitive decline among older adults as construed.

“The randomized, double-blind, placebo-controlled clinical trial included 3,069 community-dwelling participants, ages 72 to 96 years, who received a twice-daily dose of 120-mg extract of G biloba (n = 1,545) or identical-appearing placebo (n = 1,524). The study was conducted at six academic medical centers in the United States between 2000 and 2008, with a median (midpoint) follow-up of 6.1 years. Change in cognition was assessed by various tests and measures.”

In 2000, older adults that had normal to mild cognitive impairment were chosen and observed. The researchers placed the subjects into 3 distinct groups. Some were given a placebo over the 8 year period. Others were given either Ginkgo biloba or the placebo, where their group identity was not disclosed to the participant or the experimenter. The third group was randomly assigned to either of the groups. Double-blind studies are said to achieve greater scientific rigor than other types of research. The conclusion of this double-blind study is that Ginkgo biloba is not effective in reducing the incidence of Alzheimer dementia or dementia in general. In addition, no evidence was found to support any effects on memory, language, attention, visuospatial abilities and executive functions. Furthermore, no differences were detected through age, sex, race, education or baseline cognitive status.

Basically, no evidence was found to support the widely marketed fact that Ginkgo biloba slows the rate of cognitive decline.

What is Ginkgo Biloba?

Ginkgos are very large trees, normally reaching a height of 66–115 feet, with some specimens in China being over 50 m. The tree has an angular crown and long, somewhat erratic branches, and is usually deep rooted and resistant to wind and snow damage. A combination of resistance to disease, insect-resistant wood and the ability to form aerial roots and sprouts makes ginkgos long-lived, with some specimens claimed to be more than 2,500 years old. Extreme examples of the Ginkgo's tenacity may be seen in Hiroshima, Japan, where six trees growing between 1–2 km from the 1945 atom bomb explosion were among the few living things in the area to survive the blast. While almost all other plants and animals in the area were destroyed, the ginkgos, though charred, survived and were soon healthy again. The trees are alive to this day.

Extracts of Ginkgo leaves contain flavonoid glycosides and terpenoids and have been used pharmaceutically. Ginkgo supplements are usually taken in the range of 40–200 mg per day. Ginkgo has many alleged nootropic properties, and is mainly used as a memory and concentration enhancer, and an anti-vertigo agent. According to some studies, in a few cases, Ginkgo can significantly improve attention in healthy individuals. Allegedly, the effect is almost immediate and reaches its peak in 2.5 hours after intake.

Ginkgo has been used for…

• Alzheimer's disease
  
• Improving blood flow
  
• Protecting against oxidative cell damage
  
• Blocking the effects of platelet-activating factor (platelet aggregation, blood clotting)
  
• Intermittent claudication
  
• Easing the symptoms of tinnitus
  
• Improving cognition and fatigue in those with multiple sclerosis
  
• Arresting the development of vitiligo

Ginkgo may have undesirable effects, especially for individuals with blood circulation disorders and those taking anticoagulants such as ibuprofen, aspirin, or warfarin. Ginkgo should also not be used by people who are taking certain types of antidepressants (monoamine oxidase inhibitors and selective serotonin reuptake inhibitors) or by pregnant women, without first consulting a doctor.

Side effects can include…

• possible increased risk of bleeding
  
• gastrointestinal discomfort
  
• nausea
  
• vomiting
  
• diarrhea
  
• headaches
  
• dizziness
  
• heart palpitations
  
• restlessness

Other precautions…

Ginkgo biloba leaves contain long-chain alkylphenols together with the extremely potent allergens, the urushiols (similar to poison ivy). Individuals with a history of strong allergic reactions to poison ivy, mangoes, and other urushiol-producing plants are more likely to experience an adverse reaction when consuming Ginkgo-containing pills, combinations, or extracts.

The nut-like gametophytes inside the seeds are particularly esteemed in Asia, and are a traditional Chinese food. When eaten by children, in large quantities (over 5 seeds a day), or over a long period, the raw gametophyte (meat) of the seed can cause poisoning by MPN (4-methoxypyridoxine).

Bottom line...

It is very important to remember that herbal supplements are not regulated by the FDA in the US and Canada’s regulation of such health products is quite often confusing and inconsistent. Therefore, personal responsibility is essential when relying on this type of treatment.

Ginkgo Biloba Does Not Appear to Slow Rate of Cognitive Decline

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Alzheimer's, Blood Clot, Cognition, Cognitive Impairment, Ginkgo Biloba, Herbal Supplements, MAOI, Memory, Multiple Sclerosis, Oxidative Cell, Platelet-Activating Factor, SSRI, Tinnitus, Vitiligo

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