A healthy diet in childhood and middle age could reap major cognitive benefits later on, according to new research that spans nearly seven decades in the United Kingdom.

The findings come from the 1946 British Birth Cohort, in which researchers enrolled more than 3,000 people and tested their diets, cognitive outcomes, and other factors at various points between the ages of four and 70.

They found that people who ate more vegetables, fruits, legumes, and whole grains, and less sodium, added sugars, and refined grains throughout their lives had the highest cognitive abilities over time.

Among those with high cognitive abilities, eight per cent had low-quality diets, while 36 per cent had high-quality diets. Meanwhile, 58 per cent of those with low cognitive abilities had low-quality diets, and seven per cent had high-quality diets.

People who started eating healthy earlier, particularly during childhood and before age 50, were the most affected, the study found.

“This suggests that early life dietary intakes may influence our dietary decisions later in life, and the cumulative effects of diet over time are linked with the progression of our global cognitive abilities,” Kelly Cara, who worked on the study as a nutrition researcher at Tufts University in the US, said in a statement.

Cara presented the initial findings, which are not yet published, at the American Society for Nutrition’s annual conference in Chicago.

It’s not clear if the childhood impact was due to the early formation of healthy habits that lasted over time, or if young children benefited from a nutrition-spurred cognitive boost that held up as they aged.

Prior research shows that children’s earliest years are crucial for cognitive development and that nutrition plays a major role.

The findings also underscore the long-term influence of diet, given brain changes that result in cognitive decline and dementia can begin years or decades before warning signs appear, Boushra Dalile, a postdoctoral researcher at KU Leuven in Belgium who studies the link between nutrition, the gut microbiome, and stress, told Euronews Health.

Cognitive ability tends to improve into middle age but declines after around age 65. More severe health issues, such as dementia, can appear alongside cognitive decline.

“The diet needs to change for a prolonged period of time to observe any effects and to maybe mitigate any ageing-related effects,” Dalile said.

The authors noted that because they studied a mostly white population in the UK, more research is needed to understand the link between nutrition and brain health among different groups.

Overall, Dalile said the findings emphasise the role that healthy diets in childhood can have on people’s well-being, far beyond their formative years.

“The main message is to take care of diet in children … in schools, during development, at home, et cetera,” Dalile said.