New research has revealed the exact age at which one needs to stick to a healthy diet to reduce the risk of dementia. According to scientists, maintaining a nutritious diet in one's 50s and 60s may help slash the risk of dementia.

Experts from the University of Oxford observed that following a diet rich in fish, pulses and vegetables, with limited sugary treats, between the ages of 48 and 70 enhances brain activity in areas that typically decline before a dementia diagnosis. Dementia is a broad term for a decline in cognitive function that interferes with daily life. It affects memory, thinking, reasoning and the ability to perform everyday tasks. 

It is not a specific disease but rather a syndrome caused by various conditions.

The researchers observed the dietary habits of 512 Brits over 11 years and tracked 664 people's waist to hip ratio over a follow-up of 21 years. 

Those with less fat around their middle during this stage of life had an improved memory and more flexible thinking as they reached old age, the scientists observed. 

Calling the findings "important", the scientists have requested the public to think of "strategies to improve" their diet that can help in maintaining the brain structure and reducing the risk of dementia. 

The researchers wrote in the JAMA Network Open: “The global shift toward unhealthy dietary habits is associated with an increase in the prevalence of diabetes, cardiovascular disease and obesity, all of which are known risk factors for dementia.

“It is important to consider the implications of overall diet and central obesity for memory and associated brain regions, such as the hippocampus.”

MRI scans and cognitive performance tests were conducted at the start of the study and again when participants were, on average, 70 years old to monitor progress and detect signs of cognitive decline.

Researchers discovered that participants who adhered to a healthier midlife diet showed improved connectivity between the left hippocampus - crucial for memory and processing - and the occipital lobe, the brain’s primary centre for visual processing.