Less Sugar Early in Life Linked to Lower Dementia Risk Decades Later

People who consumed less sugar before birth and during their first one to two years of life were less likely to develop dementia decades later, according to an observational study of nearly 65,000 people published in the journal Neurology.

The researchers used an unusual natural experiment to investigate the question: sugar rationing in the United Kingdom during and after World War II, when access to sugar was restricted before becoming widely available again in 1953.

The study compared 64,737 people born around the rationing period, divided into three groups based on how much of their earliest development overlapped with it: 15,025 people exposed to rationing before birth and through their first year, 15,256 exposed before birth and through their first two years, and 23,774 born after rationing had ended.

"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."

Beginning when participants were an average age of 55, researchers examined medical records for dementia diagnoses over as many as 15 subsequent years. Among those exposed to rationing before birth and during their first year, 388 of 15,025 developed dementia; among those exposed through age two, 456 of 15,256 were diagnosed; and among those born after rationing ended, 504 of 23,774 developed dementia.

After accounting for age, sex, and health conditions including high blood pressure and diabetes, exposure to rationing before birth through age one was associated with a 21% lower risk of dementia compared with being born after rationing ended, and exposure through age two was associated with a 23% lower risk. Lower sugar levels in early life were also associated with dementia developing an average of 2.6 years later. In a smaller subset of participants who underwent brain imaging, those with lower early sugar exposure had greater total gray matter volume and fewer white matter hyperintensities, markers of damage to brain tissue.

The researchers cautioned that the study was observational and examined events that occurred decades earlier rather than following participants prospectively, so the findings establish an association between early sugar exposure and later dementia risk, not proof that reducing sugar directly prevents dementia.