The analysis of 64,737 UK Biobank participants found that reduced sugar exposure before birth and in infancy was associated with a 21%–23% lower risk of dementia decades later and an average 2.6-year delay in onset. Brain scans in a subgroup showed larger grey matter volume and fewer white matter hyperintensities among those with lower early-life sugar exposure. The study is observational, so it shows an association but does not prove that lowering sugar in early life directly prevents dementia.
Early-Life Sugar Restriction Linked to Lower Dementia Risk Decades Later
New research suggests that children under two who are given less sugar have about a fifth lower dementia risk. Does cutting sugar that early protect the brain or is the study picking up another hidden factor? Christin Klose/dpa
New research suggests that limiting added sugar before the age of two may be associated with a substantially lower risk of dementia later in life. The study used historical sugar rationing in the UK during and after the Second World War to compare dementia outcomes among people with different early-life sugar exposure.
Study Design and Key Findings
Researchers analysed data from 64,737 participants in the UK Biobank who were born before, during or after the period of sugar rationing (sugar rationing ran from 1940 to 1953). They grouped participants by likely exposure to reduced sugar in utero and during infancy and then followed medical records from roughly age 55 for up to 15 years to identify dementia diagnoses.
Compared with those born after rationing ended, people who experienced sugar rationing before birth and through their first year had a 21% lower risk of dementia; if rationing likely continued through the first two years of life the reduction was 23%. On average, those with lower early-life sugar exposure developed dementia about 2.6 years later than those with higher exposure.
Numbers Behind The Results
Of 15,025 participants who experienced rationing before birth and during their first year, 388 developed dementia during follow-up. Among 15,256 who likely experienced rationing through two years, 456 developed dementia. By comparison, 504 of 23,774 participants born after rationing were diagnosed with dementia. After adjusting for age, sex and health factors such as high blood pressure and diabetes, the association remained.
Brain Imaging Subgroup
A subset of participants underwent brain MRI. Those with lower early-life sugar exposure had larger total grey matter volume and fewer white matter hyperintensities—changes commonly interpreted as markers of small-vessel disease and brain tissue damage.
"Limiting sugar during the earliest stages of life may have lasting benefits for brain health," said study author Jiazhen Zheng of the Hong Kong University of Science and Technology.
Limitations And Context
Experts emphasise this is an observational study and cannot prove causation. Confounding factors linked to wartime living conditions or other early-life exposures could contribute to the results. Dr Sara Rodrigues of Alzheimer's Research UK noted that while the research is insightful, the Lancet Commission does not currently list sugar intake as an independent dementia risk factor and further research is needed before changing public-health guidance.
Bottom line: The findings add to evidence that very early-life nutrition might influence long-term brain health, but they do not prove that reducing sugar in infancy will definitively prevent dementia. Maintaining a healthy, balanced diet across the life course remains advisable.
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