Can Herbal Medicine Improve Cognitive Decline in Alzheimer’s?

Alzheimer's

Researchers in China investigated whether combining old-world herbal remedies with today’s pharmaceuticals could slow cognitive decline in Alzheimer’s patients.

Alzheimer’s disease is a neurodegenerative condition characterized by the accumulation of toxic proteins in the brain, leading to cognitive decline, loss of memory, and dementia. It is estimated that nearly 50 million people worldwide may be living with the disease in 2017 (2).

Alzheimer’s features a complex pathophysiological progression that is not yet fully understood, and this has made it difficult for clinicians to identify and treat the underlying causes or reverse the deterioration of nerve cells. Several drugs have been developed to temporarily relieve the symptoms of Alzheimer’s for affected patients. These conventional therapies (CT) fall mainly into two classes: Cholinesterase inhibitors and NMDA receptor agonists. Most drugs of this kind act on a single target and thus are sometimes combined to extend the range of benefits available to patients. However, in general, their effectiveness decreases significantly after the first three to six months.

An alternative to conventional therapies is the use of herbal medicine to treat a variety of diseases and ailments. Prevalent in East Asian countries such as China, herbal medicine has been used for thousands of years, and the evidence for their effectiveness has been empirically observed and documented. However, it has been criticized in traditional scientific circles for lacking well-defined mechanisms of action.

Many herbal medicines consist of a mixture of herbs and extracts that are dissolved in hot water and consumed. One such mixture is the GRAPE formula, which contains up to 10 different herbs. They mainly serve to boost energy, reduce inflammation, and promote circulation. The use of herbal medicine in conjunction with conventional therapies is an interesting area of research and may show promise by increasing the effectiveness of therapy for diseases such as Alzheimer’s.

A recent Chinese study conducted by a team of neurologists and herbal medicine experts sought to establish whether a hybrid of conventional and herbal therapy could prove beneficial for treating Alzheimer’s symptoms. The research, published in BMC Complementary and Alternative Medicine, featured a retrospective cohort study in which a total of 344 patients with Alzheimer’s were recruited and assigned to either a conventional therapy group (CT) or conventional therapy + herbal group (CT+H).

The researchers accessed detailed medical records for the cohort and determined levels of disease at the start of the study using neuroimaging and the mini-mental state examination (MMSE), which is a series of questions and tests to assess cognitive ability. They adjusted these scores for a subject’s education level, literacy, and a number of other factors. They then looked at MMSE data collected from the subjects in each group every three months over a period of two years and compared the results.

In general, the data showed that patients in the herbal group showed higher MMSE scores over the entire 24-month period than patients given only conventional therapy.  While conventional therapy patients dropped below baseline MMSE scores after 6 months, herbal patients only dropped below this level after 12 months. In addition, the difference between MMSE scores in the two groups became even larger in the second year of observation, illustrating that the herbal group was experiencing a symptomatic stabilizing effect from 18-24 months. Interestingly, this suggests that the benefits of a combined therapy are longer lasting than a conventional therapy alone.

These results demonstrate the benefit of added complementary herbal therapies to conventional medications.  The authors noted some limitations to the study that could be improved in subsequent research. The nature of the work involved a retrospective case population and as such selection bias is a legitimate concern. They state that a full prospective, randomized, double-blind trial is needed to confirm the results.

This study opens up many interesting questions about the use of herbal medicine in combination with today’s pharmaceuticals, and how this may be leveraged to provide added benefit to patients suffering from Alzheimer’s disease.

Written by Adriano Vissa, Ph.D.

References:
(1) Shi J et al. (2017).Adding Chinese herbal medicine to conventional therapy brings cognitive benefits to patients with Alzheimer’s disease: a retrospective analysis. BMC Complementary and Alternative Medicine. 17:533 DOI 10.1186/s12906-017-2040-5
(2) Prince, M., et al. “World Alzheimer Report 2015. The global impact of dementia. An analysis of prevalence, incidence, cost & trends; Alzheimer’s Disease International: London.” (Accessed February 17, 2016)(2015).

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