Dr Jiazhen Zheng from the Hong Kong University of Science and Technology in Guangzhou, who led the research, said the findings point towards the long-term importance of nutrition during the earliest stages of life
Restricting sugar intake during pregnancy and the first two years of life may significantly reduce the risk of developing dementia later in life, according to a new study that examined more than 65,000 people born in Britain during and after the Second World War-era sugar rationing period.
Researchers found that individuals exposed to lower sugar availability in early life had a substantially reduced risk of dementia decades later. Those who experienced sugar restrictions before birth and during their first year of life had a 21 per cent lower risk of developing dementia compared with those born after sugar rationing ended in September 1953.
The protective effect was even stronger among people who continued to have limited sugar exposure until the age of two, with researchers finding a 23 per cent reduction in dementia risk.
The study analysed medical records of 64,737 people born around the period when Britain introduced sugar rationing in 1940. During rationing, individuals were limited to around 8 ounces (227 grams) of sugar per week. Researchers tracked participants until they were aged between 55 and 70 to identify dementia diagnoses.
The findings also suggested that among those who eventually developed dementia, people exposed to lower sugar intake in early life experienced the onset of symptoms an average of 2.6 years later compared with those who had higher sugar exposure during infancy.
Brain imaging data further indicated that individuals with lower early-life sugar intake had greater grey matter volume and fewer signs of brain tissue damage associated with dementia.
Dr Jiazhen Zheng from the Hong Kong University of Science and Technology in Guangzhou, who led the research, said the findings point towards the long-term importance of nutrition during the earliest stages of life.
“Our findings suggest that limiting sugar during the earliest stages of life may have lasting benefits for brain health,” Zheng said, adding that reducing added sugar intake during pregnancy and infancy could be a beneficial step for families and communities.
The study, published in the journal Neurology, adds to previous research involving the same population group that linked lower early-life sugar exposure with reduced risks of cardiovascular conditions, including heart attacks, strokes and heart failure.
However, experts cautioned that the findings do not prove a direct cause-and-effect relationship between sugar intake and dementia prevention.
Dr Sara Rodrigues, senior research manager at Alzheimer’s Research UK, said the study was observational and could only identify associations between diet and dementia risk.
She stressed that maintaining a healthy, balanced diet remains one of the most effective ways to support brain health, while positive lifestyle changes can be beneficial at any stage of life.
Researchers said further studies are needed to understand how early nutritional environments influence brain ageing and to guide future public health recommendations.
