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Alzheimer's disease: Can ginkgo products help?

Last Update: July 18, 2013; Next update: 2016.

Ginkgo biloba could help some people with Alzheimer’s disease to perform daily activities better again. Side effects are rare, but interactions with other medications cannot be ruled out.

There is no cure for Alzheimer’s. A number of different medications and other treatment options aim to relieve the symptoms and slow down the progression of the disease. Available medications for treating Alzheimer’s include cholinesterase inhibitors and memantine, as well as extracts from the leaves of the Ginkgo biloba tree.

Research on Ginkgo biloba products

Together with researchers at the Technical University of Berlin (TU Berlin), researchers from the Institute for Quality and Efficiency in Health Care (IQWiG, Germany) carried out an assessment of ginkgo-based products. These herbal preparations are made from the leaves of the Ginkgo biloba tree. They are believed to have various benefits, such as improving blood circulation and protecting nerve cells. Ginkgo products are available without a prescription. In Germany, they can also be prescribed by doctors for people who have Alzheimer’s disease in 240 mg strength.

In order to find out whether people who have Alzheimer’s disease really benefit from ginkgo-based products, IQWiG analyzed all of the good-quality studies in this area. In these studies, people with Alzheimer’s disease were randomly assigned to two or more groups and given either ginkgo, a fake medication (placebo) or a different medication. The IQWiG researchers included seven studies in their analysis, involving just under 1,800 participants.

All of the different studies tested one particular product containing the extract EGb 761. IQWiG was not able to find any other high-quality studies on other types of gingko products. The doses used in the studies were 120 mg or 240 mg per day. Six of the seven studies were financed by the producer of the gingko extracts.

The participants had mild to moderate Alzheimer’s, but they were very different from one another in other ways. Average age in some of the trials was 65, but in others it was 78. Plus, some trials mostly included people who had already developed mental changes due to Alzheimer’s – like restlessness or depression.

All of the studies tested whether gingko extract had improved memory and whether everyday tasks such as shopping, washing themselves and doing household chores were performed better. They also looked at whether these products improved mental health – like depression or hallucinations. Other important aspects, such as quality of life for those with Alzheimer’s and their families, were only included in a few of the studies.

High doses of ginkgo extract EGb 761 could make everyday life easier

The studies showed that people who took the higher dose of the ginkgo extract (240 mg per day) were better able to perform daily activities again, like doing household chores or washing themselves. However, this effect varied strongly from study to study, so it is not possible to be sure about how many people could benefit from ginkgo and how strong its effect is. The lower dose of the ginkgo extract (120 mg per day) did not clearly influence the symptoms of Alzheimer’s disease.

The extract may have a stronger benefit in younger patients or those who have psychological problems caused by Alzheimer’s disease. The trials also provided evidence that, when taken in high doses, ginkgo could reduce psychological symptoms and improve people’s ability to remember things. It also seemed to reduce emotional stress for caregiving family members. Further research is needed to be sure of this, though.

Side effects and interactions cannot be ruled out

People who took gingko products did not have more side effects than those who took a placebo, but they stopped taking the products due to side effects more often than people in the comparison group.

It cannot be ruled out that ginkgo may interact with other drugs. It is believed that it can increase the effect of blood-thinning medications like ASA (acetylsalicylic acid) and warfarin. So it is important to let doctors know about any other medicines before starting therapy with ginkgo.

Sources

  • Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen (IQWiG). Ginkgohaltige Präparate bei Alzheimer Demenz: Abschlussbericht; Auftrag A05-19B. 29.09.2008 (IQWiG-Berichte; Band 39).
  • In the spring of 2013 we checked whether this information is still up-to-date. We did not find any recent research results that would have made it necessary to change the conclusions stated above.
  • IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

    Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. We do not offer individual consultations.

    Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

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