Early-life sugar restriction linked to lower dementia risk in later years

A groundbreaking study leverages post-war Britain’s sugar rationing to reveal that early dietary restrictions could influence dementia and Alzheimer’s risk decades later, highlighting the importance of early intervention and lifestyle factors.

Could protection against dementia begin far earlier than most people imagine? A new study published in npj Aging suggests it might, with early-life diet leaving a long shadow over brain health decades later. Researchers analysed a rare British natural experiment created by post-war sugar rationing and found that people exposed to restricted sugar intake in the womb and in early childhood had a 27% lower risk of dementia and a 46% lower risk of Alzheimer’s disease later in life. The study also linked that early exposure to signs of slower brain ageing on scans.

The findings draw on UK Biobank data from more than 60,000 people born between 1951 and 1956, a period that neatly straddled the end of rationing in 1953. That allowed researchers to compare those who spent their earliest years under tight sugar limits with those born after access had normalised. The result, according to the paper, was a striking difference in later neurological outcomes, though the authors stressed that the work shows association rather than proof that sugar directly causes dementia.

Magda Tsolaki, a neurologist and founder of the Laboratory of Neurodegenerative Diseases, told Ta Nea that there are several plausible ways early sugar exposure could matter. She pointed first to pregnancy, when maternal metabolism and insulin sensitivity may shape foetal development through epigenetic and hormonal pathways. She also cited hyperglycaemia, which can affect DNA methylation, a process important for neural development, synaptic plasticity and defence against oxidative stress. A third possible route, she said, is through the immune system, as higher sugar intake may alter maternal immune responses and raise the risk of infections.

The study fits into a wider body of research suggesting that diet can influence dementia risk across the life course. Separate UK Biobank analyses have found that higher intake of total sugars, free sugars, sucrose and certain sugary dietary patterns is associated with a greater chance of developing dementia, with some reports noting a stronger effect among women. Other research has linked sugary drinks and genetic susceptibility to poorer brain structure and higher dementia risk. Taken together, the evidence points to sugar as one part of a broader metabolic picture rather than a single cause.

Tsolaki said sugar should be seen alongside other childhood and adult habits that accumulate over time. She pointed to the World Health Organisation’s advice on physical activity, smoking cessation, limiting alcohol, balanced eating, maintaining a healthy weight, social engagement and continued mental stimulation. Education also matters, she said, because higher educational attainment can build cognitive reserve, the brain’s ability to withstand damage before symptoms appear. Limiting exposure to air pollution is another protective step. In today’s world, however, children face a new set of pressures: the screen.

The effect of phones, internet use and video games on the developing brain is less clear-cut than the impact of diet, but concern is rising. Tsolaki said technology can have both positive and negative effects, especially around the start of adolescence, when rapid biological and psychological changes are under way. Research has also suggested different patterns of problematic use between boys and girls, with girls more likely to struggle with messaging and social media while boys spend longer on gaming. Parents and teachers, she argued, should help children build critical thinking and discernment from an early age, and public health authorities could use technology itself to support education for pupils, teachers and parents alike.