In September 1953, the United Kingdom ended the sugar rationing established during World War II. Overnight, Britons’ average daily consumption practically doubled, from a sensible 41g to more than 80g. This great change, unintentionally, led to an experiment that allowed us to gain insight into the effects of sugar on cognitive decline.
Children’s brains. Data from the large UK Biobank cohort allowed two different research teams to analyze the results of rationing. Part of those findings led to a study published this year that analyzed more than 64,000 participants, including about 40,000 who experienced rationing during their fetal stage or the first two years of their lives.
what they saw Exposure to this sugar restriction in the first thousand days of life (and even while in the womb) had a 23% lower risk of developing dementia from any cause. But specifically, the risk of developing Alzheimer’s was reduced by 28%.
A second look. In parallel, another analysis studying the same population from the UK Biobank noted that people exposed to rationing had brains that appeared 0.39 years younger than their biological age on neuroimaging, in addition to registering 11% less depression.
However, the authors themselves and the American Academy of Neurology note that the end of rationing in 1953 coincided with economic recovery, major changes in maternal health care, and the introduction of new baby foods. Thus, there is a biological link, but direct causality is quite difficult to prove in observational studies with age 70.
his progress. Although there is a demonstrable effect at early stages of development, it is also interesting to study the effect of sugar on already developed brains. In this case, a 2025 study followed 158,000 adults for a decade and its conclusions pointed to a 43% increase in risk when comparing people with the lowest intake to the most free sugar intake. And in addition, the effect may be more pronounced in women.
A distinction. Not all sugars behave the same, since the most important nuance for daily nutrition was provided by a study published in 2023 that noted that the risk of dementia increases almost linearly with the consumption of sugary drinks, but does not show a significant relationship when sugar comes from solid foods.
This fits perfectly with classic data from the Framingham cohort, which found that frequent consumption of soft drinks and sugary juices was associated with poorer memory and a smaller total volume of the hippocampus, the area of the brain where learning occurs.
Because it damages the brain. The answer seems to lie in metabolism, since the study we mentioned at the beginning showed that 25.5% of the link between sugar and dementia was explained by the lifetime development of type 2 diabetes and high blood pressure.
The problem is that the damage begins before metabolic disease occurs, as noted in a 2013 study of people without diabetes. In this case, it was determined that an average blood glucose of 115 mg/dL increased the risk of dementia by 18% compared to those whose concentration was slightly lower.
the problem It comes when the pancreas can’t function properly and the cognitive clock speeds up, leading to a 24% increased risk of dementia every five years a diabetes diagnosis progresses.
There may be doubts. The puzzle surrounding cognitive decline is quite complex, and that is why there is still much research to be done to clarify what is happening in our bodies. But what seems clear is that keeping sugar at bay is one of the most effective strategies for avoiding type 2 diabetes and high blood pressure. And by protecting the body’s metabolic and vascular machinery, we are building the best shield for a healthy brain.
Picture | Taufiq Barbuiya
In Xataka | The amount of caffeine in the drinks we consume every day, is shown in this graph
