Health Supplements and Preventing Dementia: Do They Work?

It may be a common scenario in the primary care setting, and even in specialist clinics, for physicians to come across elderly patients seeking a professional opinion on the benefits of health supplements.

For those concerned with memory difficulties, they would typically ask questions such as, “Can these supplements prevent me from getting dementia?” or “Can these supplements improve my memory?”.

What advice would be appropriate: to encourage the consumption of these supplements, or not?

Incidence of dementia in Singapore is projected to increase over the years. According to the Dementia Asia-Pacific Report (2010), about 53,000 Singaporeans are estimated to be suffering from dementia in 2020. This figure is estimated to rise to 187,000 by 2050. The population in Singapore is ageing, and at risk of suffering from dementia as it grows older. Hence, it is understandable that the elderly are taking an active role in preventing dementia.

Some of the more common health supplements brought to physicians’ clinics by elderly patients, or prescribed by physicians, include Ginkgo Biloba and Omega-3 fatty acids.

Can these supplements prevent dementia?

Ginkgo Biloba is a herbal product frequently prescribed by physicians for patients with memory issues. Its proposed mechanism is its antioxidant effect, and an in-vitro study reported that it may also possess an antiamyloid aggregation effect. Hence, various studies have been done to assess the effectiveness of Ginkgo Biloba in the prevention of dementia.

To date, there are no consistent results to show its effectiveness in preventing dementia. A large randomised controlled study done in the United States (i.e. Ginkgo Evaluation of Memory (GEM) Study) reported that Ginkgo Biloba has not been effective in preventing or delaying the onset of dementia in those above 75 years old.

Due to the lack of evidence to support its effectiveness in dementia prevention, physicians will need to exercise their clinical judgment and discuss their recommendation with their patients prior to prescribing Ginkgo Biloba solely for memory complaints.

Omega-3 fatty acids can be found in fish (salmon, sardines), fish oil, chia seeds, walnuts and soy foods. Fatty acids promote cell membrane stability, fluidity and maintain synaptic connectivity. One of the postulated mechanisms of the Alzheimer’s disease pathogenesis is fatty acid oxidation by free radicals that leads to the damage of cell membranes. Omega-3 fatty acids have been reported to yield anti-inflammatory, antiarrhythmic, antiaggregant and antiatherogenic effects, thus supporting its beneficial effects on both cardiovascular and cerebrovascular function.

Multiple studies have been done to examine the role of Omega-3 fatty acid supplements in the primary prevention of dementia. To date, results have been inconsistent, and a Cochrane Review published in 2012 reported no benefits of Omega-3 fatty acid supplementation in the prevention of dementia in cognitively healthy individuals.

Nevertheless, Omega-3 fatty acid supplementation has been found to be beneficial in those with cardiovascular disease, and its prescription may benefit certain groups of individuals.

Would other health supplements such as vitamin B12, vitamin E and folate be a helpful in reducing the incidence of dementia?

Vitamin B12 and folate play an important role in lowering homocysteine levels. Elevated homocysteine levels have been associated with strokes, cardiovascular events (heart attacks) and Alzheimer’s disease.

Though the evidence is lacking for the use of vitamin B12 and folate supplements in primary prevention of dementia, patients who have B12 or folate deficiency should have their vitamin levels repleted to reduce complications of deficiency states such as anaemia and neurological sequelae.

Vitamin E has an antioxidant effect, and studies have been done in the past to evaluate its effectiveness in dementia prevention since oxidative stress may have contributed to the pathogenesis of Alzheimer’s disease. Similarly, there are no consistent results to suggest that vitamin E supplementation can prevent dementia.

There are many other health supplements that are readily available over the counter, at various pharmacies. These supplements do not require a physician’s prescription. However, as physicians, we may need to offer appropriate advice to our patients who may be taking various health supplements for a multitude of reasons, by highlighting that these supplements may interact with prescribed medications and render them less effective.

The benefits of these health supplements will need to be weighed against their side effects, the burden of polypharmacy, and the lack of evidence in dementia prevention.

 

Dr Noorhazlina Binte Ali is a Consultant of the Cognition and Memory Disorders Service, Department of Geriatric Medicine at Tan Tock Seng Hospital. She obtained her basic medical degree and Masters of Medicine (Internal Medicine) from the National University of Singapore. She is a Member of the Royal College of Physicians, UK.

Her interest is in advance care planning, end-of-life care, advanced dementia, and caregiver education.