A 23% lower risk of developing dementia is associated with limited sugar intake from before birth through age two, according to research published in Neurology. The study drew on health records from more than 64,000 people in the United Kingdom born around the end of World War II sugar rationing, which concluded in 1953. Limiting sugar exposure through only the first year of life corresponded to a 21% risk reduction, placing the two-year benefit two percentage points higher.
The rationing cohort
Researchers from The Hong Kong University of Science and Technology used the 1953 end of U.K. wartime rationing as a natural experiment. Participants born before that date were presumed to have lower early-life sugar intake; those born after faced normal supply levels. The split produced a large sample with decades of follow-up, but individual consumption was never directly measured.
Study author Jiazhen Zheng said the findings suggest that limiting sugar during the earliest stages of life may carry lasting benefits for brain health. People with lower early-life sugar exposure also developed dementia an average of 2.6 years later than those in the higher-exposure group.
An outside assessment
Dariush Mozaffarian, director of the Food is Medicine Institute at Tufts University, was not involved in the research. He credited the team's creativity in linking data across decades, then said the findings are not convincing. Wartime and postwar cohorts differed across many dimensions, including overall nutrition and calorie intake, making it difficult to attribute the observed gap to sugar alone.
Mozaffarian's recommendations for pregnant women align with existing public health guidance: focus on minimally processed foods including fruits, vegetables, beans, nuts, seeds, whole grains, fermented dairy products, and fish, while limiting ultra-processed foods high in sugar, starch, and salt.
Study limits
The authors acknowledged that the policy-as-proxy design could not eliminate the influence of other wartime variables. The study identifies an association and does not establish that reducing sugar directly prevents dementia. Confounders that shaped wartime life, from calorie supply to general diet quality, remain difficult to isolate from sugar intake specifically.
Mozaffarian's "not convincing" verdict and the authors' own caution leave the 2.6-year delay in onset as the study's least-contested output from the 64,000-person sample.