Early sugar limits lower dementia risk decades later

Researchers used the UK’s 1942‑1953 sugar rationing as a natural experiment. They compared people born while sugar was limited to those born after rationing ended. The analysis, based on 60,394 UK Biobank participants, found that those exposed to sugar restrictions in the womb and early childhood had a 27 % lower risk of dementia and a 46 % lower risk of Alzheimer’s disease. They also had 11 % lower depression and 20 % lower anxiety, and brain scans suggested slightly slower brain aging.

The first 1,000 days of life are crucial for brain development, and nutrition is a major influence. Modern diets give pregnant women, breastfeeding mothers and young children high amounts of added sugar, raising concerns that early sugar exposure could harm long‑term mental health. The study’s policy change provided a rare chance to look at the effects of limited sugar intake without a trial.

The study included 38,227 people conceived during rationing, including 9,963 who were only in utero, and 22,167 born after rationing ended. Longer exposure after birth was linked to progressively lower depression and anxiety, with the biggest benefit seen in those exposed for 24 months. Women in the rationing group showed reduced Alzheimer’s, depression and anxiety; men only showed reduced anxiety. Brain imaging of 9,053 healthy participants showed a mean brain‑age gap of 0.39 years, or about five months, and larger volumes in deep brain structures.

Long‑term brain and mental‑health effects

The findings are limited by the fact that the end of sugar rationing coincided with post‑war economic recovery and changes in infant feeding practices, which could also affect brain development. Because individual sugar intake was not measured, the study cannot prove that sugar alone caused the benefits. The authors call for replication in modern cohorts with detailed dietary data before making clinical recommendations.