Researchers have uncovered the first evidence that blood pressure drugs, called ACE inhibitors, may actually boost brainpower, as doctors have long recognized that taking the drugs may slow the onset of Alzheimer’s.

Those with high blood pressure are more at risk of developing Alzheimer’s and similar diseases, but the study found their memory and thinking skills were protected by the drugs they were taking.

ACE inhibitors – whose names  include ramipril, captopril and perindopril – have become increasingly popular in the past ten years, particularly for younger patients.

Researchers in Ireland and Canada investigated drugs which target a specific biochemical pathway called the renin angiotensin system – a hormone system which is thought to affect the development of Alzheimer’s.

The study compared the rate of cognitive decline in 361 patients diagnosed with Alzheimer’s disease, vascular dementia (caused by problems in blood supply to the brain), or a mix of both. Of that group, 85 were already taking ACE inhibitors; the rest were not.

Doctors have long recognized that taking ACE inhibitors may slow the onset of Alzheimer’s

The researchers also analyzed the impact on 30 patients, with an average age of 77 years, who were taking the drugs for the first time.

They were assessed over six months, using the Standardized Mini Mental State Examination or the Quick Mild Cognitive Impairment tests.

Those taking ACE inhibitors experienced marginally slower rates of cognitive decline than those who were not, found the study in the journal BMJ Open.

Meanwhile, the brainpower of those patients who had been newly prescribed ACE inhibitors actually improved, the experts from University College Cork in Ireland and McMaster University in Ontario, Canada found.

It is the first evidence to suggest these drugs may not only halt cognitive decline, but may actually improve brainpower.

The researchers said: “Although the differences were small and of uncertain clinical significance, if sustained over years, compounding effects may well have significant clinical benefits.”

They warn that ACE inhibitors are harmful to some patients, so if larger studies confirm they work well in dementia, it may be only certain people with high blood pressure who stand to benefit.

Previous studies have linked other forms of blood pressure medication with anti-dementia benefits.

Among the most widely used ACE inhibitors are perindopril (also known as Coversyl), ramipril (Tritace), captopril (Capoten), trandolapril (Gopten), fosinopril (Staril), lisinopril (Zestril and prinivil).

They work by stopping the body from creating the hormone angiotensin II. This has a variety of effects but essentially relaxes blood vessels and helps reduce the amount of water re-absorbed by the kidneys – helping decrease blood pressure.