A new study suggests that limiting sugar intake during the first two years of life may be associated with better brain health and a lower risk of developing dementia later in life.
However, researchers stress that the findings show a link rather than a direct cause-and-effect relationship, and more research is needed to confirm the role of sugar in long-term cognitive health.
The study, published in Neurology, analyzed health data from nearly 65,000 participants in the UK Biobank.
UK Sugar Rationing Offered a Natural Experiment
Researchers from the Hong Kong University of Science and Technology took advantage of a unique historical period following the end of post-World War II sugar rationing in the United Kingdom.
When rationing ended in September 1953, average daily sugar consumption nearly doubled—from approximately 41 grams to 80 grams. This allowed researchers to compare the long-term health outcomes of people who experienced lower sugar exposure during infancy with those born after restrictions were lifted.
The study found that individuals whose first two years of life occurred during the rationing period had a 23% lower risk of developing dementia than those born after sugar became more widely available.
Among participants who eventually developed dementia, those exposed to lower sugar levels in infancy received their diagnosis an average of 2.5 years later.
Researchers Say Findings Do Not Prove Sugar Causes Dementia
Lead researcher Jiaxin Zheng said the results suggest that reducing sugar intake during early childhood could provide long-term benefits for brain health.
However, Zheng emphasized that the research does not prove sugar directly causes dementia, and further studies are needed to better understand the relationship.
Independent Experts Urge Careful Interpretation
Independent specialists welcomed the research but cautioned against drawing firm conclusions.
Rachel Richardson noted that the study was observational and did not measure each participant’s actual sugar intake, making it impossible to establish a direct causal link.
Ian Maidment said the findings should be interpreted carefully because people born in the 1940s and 1950s experienced diets, healthcare systems and lifestyles that differ significantly from those of modern populations.
Meanwhile, Sarah Rodriguez described the study as an important contribution to dementia research but said there is no evidence that reducing sugar alone can prevent dementia.
She added that maintaining a balanced diet, staying physically active and adopting healthy lifestyle habits remain the most evidence-based strategies for supporting long-term brain health.
Early Nutrition Plays a Critical Role
Researchers highlighted that the first 1,000 days of life—from pregnancy through a child’s second birthday—are widely recognized as a crucial period for brain and physical development.
Previous studies have also linked the sharp increase in sugar consumption after the end of UK rationing with a higher risk of type 2 diabetes and high blood pressure later in life.
While the latest findings add to growing evidence that early-life nutrition may influence long-term health, the researchers stressed that the results should not be directly applied to today’s children, given the major changes in diet, healthcare and living conditions over the past several decades.
