August 12, 2026
Eating lots of sugary foods and beverages has been linked to a range of health ills: tooth decay, obesity, heart disease, diabetes, fatty liver disease. Highly processed foods high in sugar have also been tied to an increased risk of cognitive decline and Alzheimer’s disease. Now researchers report that the adverse health effects of excess sugars on the brain may extend to our earliest days, from our time in the womb to the first couple years of life.
A new study found that being exposed to less sugar before birth and during the first one to two years of life was associated with a lower risk of developing Alzheimer’s disease and other forms of dementia later in life. The study also found that lower sugar consumption early in life was associated with a delay in developing dementia.
“Our findings suggest that limiting sugar during the earliest stages of life may have lasting benefits for brain health,” said study author Jiazhen Zheng 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.”
For the study, researchers took advantage of a unique historical event: the rationing of sugar in the United Kingdom during and after World War II. The researchers looked at 64,737 men and women who were part of the U.K. Biobank, a large and long-running study that has tracked the health of British citizens over decades. All were born between 1951 and 1956, straddling the period during which sugar was scarce until it became widely available again in 1953.
Study participants were divided into groups according to when sugar rationing occurred: before birth and during their first year of life; before birth and up until they were two years old; or those born during the years when sugar rationing was no longer in effect. Those born during the sugar rationing years would have consumed far less sugar, on average, as infants than those born later, allowing for a natural experiment.
The researchers then reviewed medical records starting when participants were an average age of 55 to see who developed Alzheimer’s disease or other forms of dementia over the next 15 years. After adjusting for age, sex, and health factors like high blood pressure and diabetes, they found that people who experienced sugar rationing before birth and up to one to two years of age had a more than 20 percent lower risk of dementia compared to people born after sugar rationing.
The analysis also found dementia was delayed by about two-and-a-half years for people with lower sugar levels early in life. Those exposed to less sugar were also less likely to develop depression and anxiety as adults.
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 that increases the risk of Alzheimer’s disease. The findings were published in the journal Neurology.
“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,” Dr. Zheng said.
So many factors are involved in prenatal and early life nutrition that it is hard to pinpoint the effects of a single nutrient or food group on adult health. But the findings suggest that limiting sugar exposure early in life may have lasting benefits for the brain. Nutrition experts agree that we should limit the amount of sugar in our diet for better overall health. And as these findings suggest, the earlier we start, the better.
By ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Eric Schmidt, PhD, of The Fisher Center lab at The Rockefeller University.
Source: Jiazhen Zheng, Gregory Y.H. Lip, Zhuoni Zhang, S. W. Ricky Lee: “Association of Sugar Restriction in Utero Through Age 2 Years on Dementia Risk Later in Life.” Neurology, July 29, 2026
