Researchers say the brain improvements were small but over the years, the boost to cognitive functions could be immense. (Merck&Co/Associated Press)

Researchers in Canada and Ireland have discovered that blood pressure drugs, known as ACE inhibitors, can improve brain function while slowing down the onset of dementia.

ACE inhibitors, known by names such as ramipril and perindopril, have been already been shown in previous studies to delay the onset of dementia. What the medical community didn’t know was that these drugs may also enhance cognitive function.

The study, published in the British Medical Journal, concludes that the use of ACE inhibitors could become useful in the management of dementia.

The study examined 361 patients, all of whom had been diagnosed with Alzheimer’s, vascular dementia (triggered by lack of blood supply to the brain) or a mix of the two.

Many Alzheimer's patients suffer dementia, which can affect memory, thinking, reasoning, planning and the ability to speak.

Eighty-five of the patients were already taking the ACE inhibitors while the rest were not.

Researchers also separately tested 30 patients, put on the drugs for the first time, for changes in their brain function. The average age was 77 and participants were followed for one year.

In measuring cognitive function, scientists at McMaster University in Hamilton, Ont., and University College Cork in Ireland, tested the participants six months apart.

The 30 people who had begun taking ACE inhibitors for the first time showed improvement over the six-month period, compared with those already taking them and those not taking them at all.

The study’s authors say it could be because those put on a new drug regimen tend to be more diligent about taking the pills versus those that have been on them for years or, it might be a product of improved blood flow to the brain.

"Although the differences were small and of uncertain clinical significance, if sustained over years, the compounding effects may well have significant clinical benefits," concludes the study.

The authors do warn the ACE inhibitors can be harmful to some patients and suggest wider studies on the use of these drugs on people suffering from dementia.