Can Ginkgo Biloba Treat Alzheimers Diseases Biology Essay

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Researches have to be done to answer this question. In one of the many studies done - Ginkgo Evaluation and Memory (GEM), 2008 published in the Journal of the American Medical Association, 3069 adults aged above 75 years old participated by taking either 120 mg of ginkgo biloba twice daily or its placebo. These groups were assessed half yearly for a period of 6 years for signs of brain aging and dementia. (11)

This study was conducted at the Wake Forest Baptist, the University of Pittsburgh, John Hopkins University and the University of California-Davis. (12) GEM study is believed to be reliable as it was funded by the National Center for Complementary and Alternative Medicine. (13) The result showed that people taking ginkgo biloba and those who took the placebo have no difference in the rate of development of Alzheimer's disease. 277 people who took ginkgo biloba were diagnosed with dementia and 246 among those who took the placebo. The rate was similar in Alzheimer's disease too where 92% of the 523 who developed dementia were diagnosed with Alzheimer's as shown in figure 9. (11) (12) (14)

This tells me that ginkgo did not work efficiently as said in preventing Alzheimer's.

"I'm disappointed." "We don't think it has a future as a powerful anti-dementia drug," said Steven DeKosky, a neurologist who led the study. (1) (13)

Figure 8: Cumulative rate of all cause dementia shows that the rate did not differ in participants who took ginkgo biloba and placebo.h

737 words

In Germany, Institute for Quality and Efficiency in Health Care (IQWiG) had done a research regarding this issue. This research was done using a literature search conducted in 4 electronic databases - MEDLINE, EMBASE, Cochrane Central Register of Controlled Studies and CHID via ADEAR. The search helped IQWiG to identify and assess 7 studies which include about 1800 participants. The 7 studies mostly compared between ginkgo biloba and a placebo but Yancheva 2006 compared between ginkgo, donezepil and combined therapy of both. Of these, the two most recent and largest studies, Napreyeyenko 2007 and Schwabe 2008, showed evidence that Ginkgo helped Alzheimer's patients to cope better with daily activities. However, I learnt that there is a high inconsistency in results. The overall conclusion on the effect of ginkgo on Alzheimer's disease is still unclear. (15) (16)

In 2007, another study was done and published in the Cochrane Database of Systematic Reviews. This analysis was done using 36 clinical trials using the Specialised Register of the Cochrane Dementia and Cognitive Improvement Group (CDCIG). It is reliable because 9 of 36 trials were of sufficient duration and of sufficiently large size. The conclusion was that there are no consistent or reliable results to show the effects of ginkgo. (17)

Therefore, I presume that ginkgo may show some results in preventing the disease but may not be the ultimate solution to Alzheimer's. (18)

Ethical implications

1109 words The investigation of whether ginkgo biloba is able to treat Alzheimer's disease includes the comparison of treatment in a group of participants who are given either ginkgo or a placebo. The study have to take into consideration the possibility that ginkgo is able to treat Alzheimer's disease. If a positive result is achieved, the other half of the participants would have been given the placebo for a long period when they could have been treated with ginkgo biloba and recovered. It would be unethical to allow the health of the control group to be left unattended. Besides that, they may be some side effects from ginkgo biloba and participants who took the ginkgo in clinical trials may be adversely affected instead of having any benefit. Also, ginkgo being sold at large in pharmacies and patients taking without consultation is rather worrying.

Social and economical implications

Figure 9: Number of Alzheimer's patients worldwide. i [a] bAccording to the Alzheimer's disease International (ADI) there are currently about 30 million people worldwide who are affected by Alzheimer's disease and dementia and it is expected to rise to above 100 million by 2050. (19) (20) Discovery of a treatment would mean millions of people would be able to have a longer lifespan as it is the 6th leading cause of death in United States and the top 10 leading cause of death in United Kingdom. (21) (22) The worldwide societal cost for dementia and Alzheimer's disease is US$315.4 billion. (19) This means if ginkgo succeeds in the trials it could cut down worldwide expenses and there will be a longer average lifespan - killing two birds with one stone.

Benefits and risks

Although ginkgo biloba is said to have inconsistent results when being tested to treat Alzheimer's disease there is still some evidence that it improves cognition and memory. (16) The trials are important and significant although it did not prove the efficacy of ginkgo because it helped the researchers as they got insights on the disease itself. This will contribute to further studies to find a cure to Alzheimer's disease. (12) (23) Besides that, the study is important as it would inform the public who has been putting hope on ginkgo. It would alarm the public of the non-evidence based advertisements on ginkgo and inform them of other non-pharmacological treatment available.

1457 words Ginkgo biloba which underwent numerous researches appears to be rather safe with not much side effects because those who took the placebo have similar side effects as to those who took the ginkgo. (13) (23) However, evidence also showed that more patients quit the study due to negative impacts from the Ginkgo than with the placebo. (16) Complaints on minor symptoms include headache, nausea, diarrhoea and allergic reactions. (24) (25) Haemorrhage and bleeding in the brain has also been reported with the use of ginkgo. (26) (13) (24) (25) (27) Thus, it is advised that those on anticoagulant drugs like warfarin should not take ginkgo at the same time due to the increased risk of bleeding. Risks increase as people are unaware that herbs too may cause adverse effects.

Alternative treatments

Cholinesterase inhibitors (ChEIs)

Figure 10: Action of acetylcholine. j There is no cure to Alzheimer's disease currently but there are ways to reduce the symptoms. Alzheimer's patients lack acetylcholine - a neurotransmitter that transmit nerve impulses and form new memories. ChEIs are found to protect the acetylcholine from being broken down as shown in figure 11. Most physicians prescribe donezepil, rivastigmine or galantamine where donezepil treats mild to severe Alzheimer's disease while the other two only treat mild to moderate Alzheimer's disease. They however bring about side effects as in figure 12. (28) (29) (30)

1592 words"There is now a substantial evidence base demonstrating that cholinesterase inhibitors are a clinically effective treatment for people with Alzheimer's disease." (31)

Figure 11: Standard drugs for Alzheimer's disease. k

Non-pharmacological therapies

While cholinesterase inhibitors treat cognitive symptoms, non-drug treatments are used to manage behavioral symptoms such as depression, hallucination, suspicion and memory problems. (29)

Non-drug treatments include: (32)

Music therapy

Researches provided evidence that music therapy helps in relaxation and is effective in reducing shouting in Alzheimer's patients where their verbally disruptive behaviours decreased by 31%. (33)

Bright light therapy

1699 wordsThis therapy improves sleeping in the patients and slows deterioration by 5%. The therapy requires one to sit in front of a light box that provides about 30 times more light than an average office light. (34)


This therapy - recently largely promoted - includes the usage of essential oils applied by massage or delivered via inhalation. It helps in reducing stress, promoting relaxation and thus reducing agitation. (35)

Figure 12: Aromatherapy. l


One of the major studies on gingko biloba I referred to was conducted by IQWiG and its report is in reference (16). I find this report reliable because the specification of the report includes a minimum observation period of 16 weeks. "The period meets the recommendation of the Drug Commission of the German Medical Profession . The studies also include the use of the standardised Ginkgo extract EGb 761 produced by the German manufacturer Dr Willmar Schwabe Arzneimittel & Co. KG (Karlsuhe, Germany)." (16) I find the results to be rather similar to the study published in the Journal of the America Medical Association . I think that it is credible as the Federal Ministry of Health of Germany is their contracting agency.

1997 words Another source referred is the book in reference (7) by Marwan Sabbagh, M.D. I find it valid as it is up-to-date being published in 2008. The author a geriatic neurologist, founder of the Sun Health Research Institute's Cleo Roberts Center for Clinical Research is also an investigator for many Alzheimer's trials. As he is also a physician specialising in Alzheimer's, his credibility is high and thus facts from the book are unlikely to be biased. Besides that, the facts about flavonoids and antioxidants agree with reference (9), a journal article from MEDLINE. MEDLINE has the honor of the HONcode confirming it meets appropriate standards and provides credible medical information. MEDLINE has also achieved the World Summit on the Information Society award. (36) Owing to recognitions from nonprofit organizations, I believe that this source is reliable and valid.