Consuming less sugar in utero and during the first one to two years of life is associated with a 21% to 23% lower risk of dementia and a delay in onset by an average of 2.6 years in older age, according to a study published July 29, 2026, in Neurology, the medical journal of the American Academy of Neurology. Researchers led by Jiazhen Zheng analyzed data from 64,737 people born in the United Kingdom before and after World War II sugar rationing to uncover these long-term cognitive health links.
The Post-War UK Cohort and Sugar Rationing Data
Researchers evaluated health records from individuals born around the time sugar rationing ended in the United Kingdom in 1953. By comparing people born before rationing ended to those born afterward, the study captured dietary conditions during early development periods. Participants were tracked starting at an average age of 55 using medical records to monitor dementia diagnoses over a 15-year period.
Out of 15,025 individuals who experienced sugar rationing before birth and through their first year of life, 388 developed dementia. Among 15,256 people who experienced rationing before birth and up to age two, 456 developed dementia. By comparison, 504 out of 23,774 participants born after rationing ended developed the condition, according to the findings published in Neurology.
Did you know? Sugar rationing in the UK during World War II severely restricted added sweeteners until controls were completely lifted in 1953, creating a massive natural experiment for modern epidemiologists studying long-term health outcomes.
Risk Reduction and Brain Scan Findings
After adjusting for age, sex, and health factors such as high blood pressure and diabetes, the study revealed stark contrasts. Individuals who experienced sugar restriction before birth and up to one year old exhibited a 21% lower risk of dementia compared to those born after rationing. Those whose restriction lasted through age two saw a 23% reduction in risk.
Furthermore, brain scans from a smaller subset of participants showed physical differences. People with lower early-life sugar exposure demonstrated higher total gray matter volume and lower levels of white matter hyperintensities, which serve as a marker of brain tissue damage, according to the study authors.
Study Limitations and Next Steps
Study author Jiazhen Zheng, PhD, of The Hong Kong University of Science and Technology in Guangzhou, China, noted that limiting added sugars during pregnancy and infancy may represent a beneficial step for families and communities. However, researchers emphasize that the work is observational and relies on historical events rather than tracking individuals prospectively over time.
Because the research demonstrates an association rather than direct causation, further studies are necessary to fully understand how early-life dietary exposures influence dementia risk decades later and to shape future public health strategies.
Frequently Asked Questions
Does the study prove that eating less sugar prevents dementia?
No. The study establishes an association between lower early-life sugar intake and a reduced risk of dementia, but it does not prove direct causation.
How much was dementia delayed for those with lower early-life sugar intake?
Participants with lower sugar levels early in life developed dementia an average of 2.6 years later than their counterparts.
What specific age groups were analyzed in the research?
Researchers examined participants who experienced sugar rationing in utero and up to age one, as well as those who experienced it in utero and up to age two.
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