Long‑term effects of sugar on the brain and mental health

To study this relationship, the team analyzed medical data from more than 45,000 participants in the UK Biobank project, who were born between 1951 and 1956. This period proved to be particularly valuable for science: it covers the time when post‑war sugar rationing was gradually being abolished in the UK. The scientists were able to compare people who, at an early age, lived under conditions of sugar restriction, with those who experienced its gradual introduction into their diet. The participants were divided into groups depending on whether they fell within the sugar distribution norms before birth and in the first months and years of life — up to 6, 12, 18, or 24 months. The analysis also included a control group of people of similar age who were born after the normalization was abolished, and a group of children from Ireland.

It turned out that the lowest risk of developing anxiety was observed in those who spent the longest time under conditions of limited access to sugar — from the stage of intrauterine development to the age of two. This link was particularly evident in women: those who either did not experience any regulation at all or experienced it only for a short time were more likely to suffer from anxiety disorders in adulthood.

In addition to its impact on mental health, early sugar consumption also affected eating habits: people who lived under sugar restrictions for a longer period tended to reach for desserts less often in adulthood and generally showed a lower inclination towards sweets. Thus, the first years of life can shape taste preferences for decades to come.

The impact on the brain turned out to be no less significant. Researchers compared MRI data with information about access to sugar and identified significant differences in the volume of gray matter. Of the 139 brain regions measured, differences between the groups were found in 80, and in 11 of the 80 regions, the differences were particularly pronounced, including in parts of the cerebellum. This suggests that sugar at an early age can affect neurodevelopment and form stable features of brain structure.

The link between early sugar consumption and depression was also observed, but it weakened after statistical adjustment. The data suggest that dietary habits in adulthood have a stronger influence on the development of depression, whereas anxiety is more closely tied to the earliest stages.

According to Dr. Hana Navratilova, who led the study, understanding how sugar affects physical and mental health throughout the lifespan could become an important reference point for shaping public policy in the field of nutrition. Professor Nofar Giefman emphasizes the uniqueness of the data collected: it is unlikely that a similarly large‑scale and natural experiment will appear in the future, in which a large number of people had their sugar intake strictly restricted at an early age and then gradually returned to their diet.

It turns out that dietary conditions at the very beginning of life can leave a deep and long‑lasting mark not only on brain structure and eating habits but also on vulnerability to anxiety disorders decades later.