MINNEAPOLIS — Consuming less sugar in utero before birth and during the first one to two years of life was associated with a lower risk of developing dementia later in life, according to a study published July 29, 2026, in Neurology® , the medical journal of the American Academy of Neurology . The study also found that lower sugar consumption early in life was associated with a delay in developing dementia. The study does not prove that lower sugar consumption directly prevents dementia; it only shows an association between sugar and dementia risk.
For the study, researchers looked at 64,737 people who were born before and after World War II sugar rationing in the United Kingdom. Sugar was rationed during and after the war and then became widely available again in 1953.
"Our findings suggest that limiting sugar during the earliest stages of life may have lasting benefits for brain health," said study author Jiazhen Zheng, PhD, of The Hong Kong University of Science and Technology in Guangzhou, China. "These results highlight the potential importance of early-life nutrition in reducing the risk of dementia decades later."
Participants were grouped by when sugar rationing occurred: before birth and during their first year, before birth and up to two years old, or no sugar rationing.
Starting when participants were an average age of 55, researchers used medical records to determine which participants were diagnosed with dementia up to 15 years later.
Of 15,025 who experienced sugar rationing before birth and during their first year of life, 388 developed dementia. Of 15,256 who experienced sugar rationing before birth and during their first two years of life, 456 developed dementia. Of 23,774 born after sugar rationing, 504 developed dementia.
After adjusting for age, sex, and health factors like high blood pressure and diabetes, researchers found that people who experienced sugar rationing before birth and up to one year old had a 21% lower risk of dementia compared to people born after sugar rationing. And those who experienced it before birth and up to two years old had a 23% lower risk of dementia.
Researchers also found for people with lower sugar levels early in life, dementia was delayed an average of 2.6 years.
A smaller group of participants also had brain scans. People with less sugar in early life had higher total gray matter volume and lower levels of white matter hyperintensities, a marker of brain tissue damage.
"Limiting added sugars during pregnancy and infancy may be one beneficial step that families and communities can take, but further research is needed to better understand how these early exposures influence dementia risk and to guide public health strategies," Zheng said.
A limitation of the study was that it was observational and relied on events that happened in the past, instead of following people over time.
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