A new study suggests that limiting sugar consumption in the womb and during the first two years of life could significantly reduce the risk of developing dementia decades later. Researchers analysed data from nearly 65,000 people, including those who lived through wartime sugar rationing in Britain, and found that early-life sugar restriction was linked to a 21-23% lower risk of dementia.
Study draws on wartime rationing data
Published in the journal Neurology, the study used records from the UK Biobank, a large biomedical database. It focused on 64,737 people born before and after sugar rationing was introduced in the UK in 1940 by Neville Chamberlain's government. Rationing, which limited sugar and other foods, remained in effect until 1953. Of the participants, 40,963 had been exposed to sugar rationing during fetal development or early childhood, while 23,774 were born after rationing ended.
The unique historical context provided a natural experiment. Earlier research on this same group had already revealed a lower risk of heart attack, heart failure, and stroke among those who grew up with limited sugar. The new study extends those findings to dementia, a condition that affects millions worldwide.
Key findings on dementia risk
The researchers discovered that individuals exposed to sugar rationing before birth and up to age one had a 21% lower risk of developing dementia compared with those born after rationing ended. For those whose sugar intake remained restricted until age two, the risk reduction was even greater, at 23%. Additionally, among those who did develop dementia, the onset was delayed by an average of 2.6 years in the rationed group.
These associations persisted even after accounting for age, sex, and health conditions such as high blood pressure and diabetes. The researchers concluded that reducing sugar exposure during critical developmental windows may offer lasting protection for brain health.
Expert perspectives
Study author Jiazhen Zheng, from the Hong Kong University of Science and Technology in Guangzhou, China, said: "Our findings suggest that limiting sugar during the earliest stages of life may have lasting benefits for brain health. These results highlight the potential importance of early-life nutrition in reducing the risk of dementia decades later."
Zheng added: "Limiting added sugars during pregnancy and infancy may be one beneficial step that families and communities can take, but further research is needed to better understand how these early exposures influence dementia risk and to guide public health strategies."
Independent commentary and limitations
Dr Sara Rodrigues, from Alzheimer's Research UK, commented on the study's significance. "Research like this helps us better understand how dementia risk develops across our lifetime and could help shape future approaches to protecting brain health," she said. "However, it's important to remember that this was an observational study."
"This means it can identify links between diet and dementia risk, but it cannot prove that eating less sugar directly prevents dementia," Rodrigues explained. She also noted that the Lancet Commission, one of the most comprehensive reviews of dementia risk, does not currently list sugar intake as a standalone risk factor.
"More research is needed to better understand the potential relationship between sugar intake and the development of dementia. For now, our advice at Alzheimer's Research UK remains unchanged. Eating a healthy, balanced diet is one of the best ways to support your brain health and it's never too late to make positive changes."
Broader implications
The findings add to a growing body of evidence that early-life nutrition plays a crucial role in long-term health. Dementia is a major global health challenge, with no known cure, so identifying modifiable risk factors is essential. This study suggests that public health policies focused on reducing sugar intake among pregnant women and young children could have far-reaching benefits, potentially reducing the burden of dementia in future generations.
While the study is observational and cannot prove causation, the results align with current recommendations to limit added sugars in the diet. For families, this may mean being mindful of hidden sugars in processed foods and sugary drinks during pregnancy and infancy. For researchers, it opens new avenues for investigating how early metabolic programming influences brain ageing.
