Healthy eating, exercise and brain training could slow down cognitive decline in older adults, according to a recent study.

Researchers led by Professor Miia Kivipelto from the Karolinska Institutet in Sweden assessed the effects on brain function of a comprehensive intervention aimed at addressing some of the most important risk factors for age-related dementia, such as high body-mass index and heart health.

For the study, researchers collected and analyzed data from more than 1,000 people from across Finland, aged 60 to 77 years old. Half of the participants were randomly allocated to the intervention group, and half allocated to a control group, who received regular health advice only. All of the study participants were deemed to be at risk of dementia, based on standardized test scores.

The intensive intervention consisted of regular meetings over two years with physicians, nurses, and other health professionals, with participants given comprehensive advice on maintaining a healthy diet, exercise programs including both muscle and cardiovascular training, brain training exercises, and management of metabolic and vascular risk factors through regular blood tests, and other means.

After two years, study participants' mental function was scored using a standard test, the Neuropsychological Test Battery (NTB), where a higher score corresponds to better mental functioning. Overall test scores in the intervention group were 25 percent higher than in the control group. For some parts of the test, the difference between groups was even more striking -- for executive functioning (the brain's ability to organize and regulate thought processes) scores were 83 percent higher in the intervention group, and processing speed was 150 percent higher. Based on a pre-specified analysis, the intervention appeared to have no effect on patients' memory. However, based on post-hoc analyses, there was a difference in memory scores between the intervention and control groups.

"Much previous research has shown that there are links between cognitive decline in older people and factors such as diet, heart health, and fitness. However, our study is the first large randomized 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," Kivipelto said.

The study participants will now be followed for at least seven years to determine whether the diminished cognitive decline seen in this trial is followed by reduced levels of dementia and Alzheimer's diagnoses.

The findings are detailed in The Lancet.