The roots of dementia may reach much further back in life than most people imagine.
A new study suggests that sugar intake during pregnancy and the first two years after birth could be connected with brain health more than half a century later. The research was published online July 29 in the medical journal Neurology.
Researchers from The Hong Kong University of Science and Technology and other institutions studied a unique moment in British history. Sugar was rationed in the United Kingdom for years after World War II, limiting how much families could buy. Those restrictions ended in September 1953, after which sugar consumption increased.
That sudden change gave scientists an unusual opportunity. People born shortly before and after rationing ended shared much of the same country, culture and historical period, but their earliest exposure to sugar differed. Researchers could therefore examine whether this early nutritional difference was associated with health decades later.
The study included 64,737 UK Biobank participants born around the end of rationing. About 41,000 had experienced sugar rationing while in the womb or during early childhood, while nearly 24,000 had not. Researchers compared these groups for dementia, brain structure and thinking abilities.
The period from conception to age two is often called the first 1,000 days. During this time, the brain grows rapidly and the body develops systems that control metabolism, hormones and energy use. Poor nutrition during this stage can affect development, which is why scientists are increasingly interested in its possible influence on diseases of older age.
The results showed that people exposed to sugar rationing during pregnancy and their first year of life had a lower rate of dementia later on. Their rate of Alzheimer’s disease was also lower. Those exposed for longer, through roughly the first two years after birth, showed an even stronger association.
For people exposed during pregnancy and through ages one to two, the rate of all types of dementia was about 23% lower than in the unexposed group. Their rate of Alzheimer’s disease was about 28% lower. These percentages describe differences between groups and do not mean that an individual’s personal risk falls by exactly the same amount.
There was also an interesting difference in the timing of disease. Longer exposure to rationing was associated with overall dementia appearing about two and a half years later. Alzheimer’s disease appeared almost three years later on average, while vascular dementia was delayed by about two and a half years.
The scientists did not rely only on dementia diagnoses. Brain imaging showed that people exposed to rationing early in life tended to have more gray matter and fewer signs of damage in the brain’s white matter. They also performed somewhat better on tests involving reasoning and the speed of processing information.
These brain findings matter because Alzheimer’s disease develops gradually. Changes can begin many years before obvious memory loss. Finding similar patterns across diagnoses, brain scans and thinking tests strengthens the possibility that early nutrition may have lasting links with brain aging.
The researchers also looked at diabetes and high blood pressure. Together, these conditions appeared to explain about 25.5% of the association between early sugar rationing and dementia. This is biologically plausible because both diabetes and hypertension can damage blood vessels and are established risk factors for cognitive decline.
One possible explanation is that very high sugar intake early in life could influence the body’s long-term metabolism. Another is that lower sugar intake helps reduce later risks such as diabetes or high blood pressure. But the study cannot determine exactly which biological pathway is responsible.
It is also important to distinguish naturally occurring sugars from added sugar. Fruit, vegetables and milk contain sugars along with nutrients the body needs, while many sweets and sugary drinks provide large amounts of added sugar. The historical rationing examined in the study mainly affected access to added sugar and sweets rather than eliminating carbohydrates from children’s diets.
The research has an unusual advantage because the end of rationing created a clear historical dividing point that was unrelated to an individual family’s later dementia risk. This makes the comparison stronger than a typical study that simply asks older adults what they ate many decades earlier. The large UK Biobank sample also allowed researchers to examine several measures of brain health.
Nevertheless, this was not a randomized clinical trial, so it cannot prove cause and effect. Other changes around the end of rationing could have influenced health, and UK Biobank volunteers differ in some ways from the general population. Genetic background, education, adult diet, exercise and many other factors also contribute to dementia risk.
The findings should therefore not be interpreted as evidence that strict sugar restriction will prevent Alzheimer’s disease. Pregnancy and early childhood require enough energy and nutrients for healthy development, and extreme diets could be harmful. The study instead raises a more focused question about the possible long-term effects of excessive added sugar during early development.
The research is important because most dementia prevention studies concentrate on middle age or older adulthood. This work suggests that scientists may need to consider a much longer timeline, beginning before birth. If future studies confirm the association, recommendations for healthy early-life nutrition could eventually have benefits that extend into old age.
For now, the results provide a fascinating clue rather than a prescription. They suggest that what happens during the first 1,000 days may leave traces that remain relevant to brain health many decades later. Longer follow-up and studies in other populations will be needed to determine how much early sugar exposure truly contributes to dementia and whether changing it can reduce future risk.
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Source: The Hong Kong University of Science and Technology.
