Less Sugar Early in Life, Less Dementia Decades Later

What if protection against dementia began even before we were born? A study that took advantage of the end of sugar rationing in the United Kingdom uncovered a surprising association: individuals who had less access to sugar during gestation and their early years of life showed, decades later, a lower risk of dementia, brains with more favorable characteristics, and better performance on certain cognitive tests.

Nutrition during pregnancy and the first years of life is crucial for brain development and can also influence health throughout one's lifespan. Since excessive sugar consumption can contribute to issues such as obesity, type 2 diabetes, and high blood pressure, all factors linked to the risk of dementia, researchers sought to investigate whether the amount of sugar available early in life might be related to brain health decades later.

To do this, they leveraged a unique historical situation in the United Kingdom. During and after World War II, sugar was rationed; however, this restriction came to an abrupt end in September 1953.

Thus, individuals born around this time had different experiences: some spent their gestation and early years of life when sugar was still rationed, while others were born after rationing ended and had greater access to it. This shift allowed researchers to compare similar groups that had different levels of exposure to sugar during early life.

The study analyzed 64,737 participants from the UK Biobank who were born around the time rationing ended. Based on their date of birth and estimated gestational period, the researchers categorized individuals according to the duration of their exposure to rationing: during gestation only; during gestation and the first year of life; during gestation and the first two years of life; or with no exposure at all.

They then cross-referenced this information with medical records to determine who developed dementia, Alzheimer’s disease, or vascular dementia later in life.

The researchers also assessed the brain health of a subset of the participants. To do this, they used magnetic resonance imaging (MRI) to measure brain characteristics, such as gray matter volume and changes in white matter.

They also administered tests of reasoning and information-processing speed. Furthermore, they employed statistical analyses that accounted for differences among the participants, as well as factors that could influence the risk of dementia. They also investigated whether type 2 diabetes and high blood pressure might help explain the findings.

The results showed that individuals exposed to rationing during gestation and the first year of life had a 21% lower risk of dementia in general and approximately 23% lower risk of Alzheimer’s disease. When this exposure extended through the first two years of life, the reduction was approximately 23% for dementia and 28% for Alzheimer’s disease. In this group, the onset of dementia was also delayed by an average of about 2.55 years, while the onset of Alzheimer’s disease was delayed by nearly three years.

Brain imaging supported this association. Individuals who spent their early years during the rationing period exhibited, on average, a greater volume of gray matter, fewer white matter abnormalities, and better performance on tests of processing speed and reasoning.

Type 2 diabetes and high blood pressure together accounted for approximately 25.5% of the observed association, suggesting that part of the effect may be linked to metabolic health throughout one’s life.

However, the researchers point out that the study shows an association, rather than proving that consuming less sugar in childhood prevents dementia. It remains unclear which mechanisms might explain this relationship. The findings raise the possibility that diet during pregnancy and the early years of life could influence brain development and metabolic health in ways that only become apparent many decades later.

READ MORE:

Association of Sugar Restriction in Utero Through Age 2 Years on Dementia Risk Later in Life

Jiazhen Zheng, Gregory Y.H. Lip, Zhuoni Zhang, and S. W. Ricky Lee

Neurology. August 25, 2026 issue 107 (4) e218313

DOI: 10.1212/WNL.0000000000218313

Abstract: 

Excess sugar intake in early life may affect long-term brain health, but evidence for dementia is limited. We used the abrupt end of UK sugar rationing in September 1953 as a natural experiment to test whether exposure to sugar rationing during different windows within the first 1,000 days from conception was associated with adult risk of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VaD). We analyzed UK Biobank participants born around the end of UK sugar rationing. Exposure was classified as rationing in utero only, in utero plus the first year of life, in utero plus 1–2 years of life, or no exposure. Incident dementia was identified from linked ICD-10 records. MRI of the brain and cognitive function were assessed in the imaging subcohort. Adjusted Cox and Gompertz models estimated HRs and 95% CIs, Fine–Gray models accounted for competing risk, and mediation analyses evaluated type 2 diabetes and hypertension. Among 64,737 participants included in the analysis, the mean age at recruitment was 54.6 years, and 56.4% were women; 40,963 were exposed to sugar rationing during fetal and/or early-childhood life, and 23,774 were unexposed. Compared with unexposed individuals, sugar rationing in utero plus the first year of life was associated with lower hazards of all-cause dementia (HR, 0.79; 95% CI 0.66–0.94) and AD (HR, 0.77; 95% CI 0.59–1.00). Similar or slightly stronger associations were observed for exposure in utero plus 1–2 years (all-cause dementia: HR, 0.77; 95% CI 0.63–0.95; AD: HR, 0.72; 95% CI 0.53–0.98). Exposure in utero plus 1–2 years was associated with delayed onset of all-cause dementia by 2.55 years, AD by 2.87 years, and VaD by 2.49 years. Early-life sugar rationing was also associated with higher total gray matter volume (β, 3.27; 95% CI 0.46–6.07), lower white matter hyperintensity volume (β, −0.64; 95% CI −0.97 to −0.31), and better performance in processing speed and reasoning. Incident type 2 diabetes and hypertension jointly mediated 25.5% of the association. Sugar restriction in the first 1,000 days was associated with lower dementia hazards, delayed onset, and more favorable brain-health profiles. These results support early-life sugar reduction as a potential strategy for dementia prevention.