Intensive lifestyle and health interventions on memory and thinking can help older people at higher risk of dementia.

Healthy eating, exercise, brain-training and health management can slow down mental decline in older people, according to a Finnish study.

Scientists studied 1,260 Fins aged 60-to-77, all of whom were considered to be at risk of dementia.

Standard mental functioning tests at the end of two years showed that participants randomly allocated to the program had 25 per cent better test scores than those receiving regular health advice.

For some tests, differences between groups were more striking.

For executive functioning - the brain's ability to organise and regulate thought processes - scores were 83 per cent higher in the program group and for processing speed 150 per cent higher.

Lead researcher Professor Miia Kivipelto, from the Karolinska Institute in Stockholm, Sweden, said previous research had shown links between cognitive decline in older people and factors such as diet, heart health, and fitness.

"Our study is the first large randomised controlled trial to show that an intensive program aimed at addressing these risk factors might be able to prevent cognitive decline in elderly people who are at risk of dementia," she said.

Findings from the Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability are reported in the The Lancet.

Dr Simon Ridley, from Alzheimer's Research UK, said the initial results were promising.

"They suggest that a combination of improving cardiovascular health and keeping mentally active could slow decline in some aspects of our thinking, but it's unclear which of the interventions carried the greatest benefit.

"Further studies like this will be vital to help us unpick the best approaches to maintaining brain health as we age and potentially helping to reduce the burden of dementia in society," he said.