npj Aging: Limiting sugar in early life linked to nearly 50% lower Alzheimer's risk

Restricting sugar intake during the first 1,000 days of life—from conception to around two years of age—may significantly reduce the risk of dementia and Alzheimer's disease decades later, according to a study published in npj Aging. The research was conducted by scientists at Guangzhou Medical University in China.

The study took advantage of a unique "natural experiment" created by sugar rationing in the United Kingdom during and after World War II. At that time, sugar was strictly rationed, and children under the age of two did not receive a separate sugar allowance. After rationing ended in September 1953, average adult sugar consumption nearly doubled—from 41 to 80 grams per day—while children's consumption of sweets more than doubled.

Researchers analyzed data from 60,394 participants in the UK Biobank who were born between 1951 and 1956. Individuals whose first 1,000 days of life coincided with the period of sugar rationing had a 27% lower risk of all-cause dementia and a 46% lower risk of Alzheimer's disease compared with those born after rationing ended.

The study also found that participants exposed to lower sugar intake early in life were 11% less likely to develop depression and 20% less likely to experience anxiety. No association was found between early sugar restriction and the risk of Parkinson's disease.

Brain MRI scans revealed additional differences. Participants who experienced sugar restriction during infancy had brains that appeared, on average, 0.39 years younger than their chronological age, along with larger hippocampal and thalamic volumes—brain regions involved in memory and cognitive function.

According to senior author Bing Zhang, a specialist in geriatric medicine, the protective effect may stem from metabolic programming during the first 1,000 days of life, a critical period when the brain develops rapidly and is particularly sensitive to nutritional influences.

The researchers caution that the study does not prove that reducing sugar directly prevents dementia. Because it is an observational study and included only 307 dementia cases, the findings should be interpreted carefully. Nevertheless, the authors say the results support limiting added sugar during early childhood as a potential long-term investment in brain health.

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