An analysis of UK Biobank data found that people who were exposed to Britain’s sugar rationing in the womb and during their first years of life had a 27% lower risk of dementia, a 46% lower risk of Alzheimer’s disease, an 11% lower risk of depression, and a 20% lower risk of anxiety compared with people born after rationing ended. Brain scans also suggested slightly slower brain aging in this group. The paper was published in npj Aging.
Neurological and psychiatric disorders such as dementia, depression, and anxiety place a growing burden on individuals, healthcare systems, and societies worldwide. Increasing evidence suggests that some of the factors influencing these conditions may begin acting very early in life, during sensitive periods of brain development.
The first 1,000 days of life, beginning in pregnancy and continuing through infancy, are considered especially important for shaping long-term health. Nutrition is one of the major environmental influences during this period because the developing brain depends heavily on an adequate and balanced supply of nutrients. At the same time, modern diets often expose pregnant women, breastfeeding mothers, and young children to large amounts of added sugar.
This has raised concerns that high sugar intake early in life could have lasting effects on brain development and later mental health. Biological studies suggest that excessive sugar exposure may promote inflammation and disturb systems involved in the body’s response to stress. Poor maternal metabolic health, including elevated blood glucose, has also been associated with a greater risk of conditions such as attention-deficit/hyperactivity disorder and anxiety in children.
Study author Xingji Lian of Guangzhou First People’s Hospital and Guangzhou Medical University in China and colleagues set out to examine whether limited sugar exposure early in life was linked to mental and brain health in older age. Because randomized trials restricting sugar during pregnancy and infancy would be impractical and unethical, the researchers turned to history. The U.K. rationed sugar between 1942 and 1953, limiting intake to levels in line with current dietary guidelines and providing no sugar ration for children under two years of age.
Sugar rationing ended in September 1953, and average adult sugar consumption nearly doubled almost immediately, while intake of other major foods remained stable. This allowed the researchers to treat the policy change as a natural experiment, comparing people conceived while rationing was in place with people conceived after it ended. A previous study using the same natural experiment, published in Science, linked early exposure to rationing to lower risks of type 2 diabetes and high blood pressure.
The researchers drew on the UK Biobank, a large long-term research project that has collected genetic, health, lifestyle, and medical imaging data from about half a million people in the United Kingdom. They examined diagnoses of dementia, Alzheimer’s disease, Parkinson’s disease, depression, and anxiety, along with brain scans that allowed them to estimate each person’s brain age.
The analysis included 60,394 participants born between October 1951 and March 1956. Of these, 38,227 were conceived while rationing was in place (born between October 1951 and June 1954), including 9,963 born between October 1953 and June 1954, who were exposed to rationing only in the womb. The remaining 22,167 participants, born between July 1954 and March 1956, served as the comparison group, and a subset of 9,053 participants without brain disorders had brain scans.
People exposed to rationing both in the womb and after birth had lower risks of dementia, Alzheimer’s disease, depression, and anxiety than the comparison group, after the researchers accounted for factors such as region and month of birth, socioeconomic status, education, family history, and genetic risk scores. Those exposed only in the womb had a 10% lower risk of anxiety but showed no meaningful differences for the other conditions. Rationing was not associated with Parkinson’s disease.
Because participants were only in their late 60s or early 70s by the end of follow-up, the dementia findings rested on relatively few cases: 307 people had been diagnosed with dementia and 123 with Alzheimer’s disease. By comparison, 7,015 had been diagnosed with depression and 4,011 with anxiety.
Longer exposure to rationing after birth was associated with progressively lower risks of depression and anxiety, with the associations becoming more pronounced after six months. For example, participants exposed to rationing for 12 months after birth had a 23% lower risk of depression and a 28% lower risk of anxiety, and the lowest risks were seen in those exposed for 24 months. No such pattern appeared for dementia or Alzheimer’s disease.
The associations were most consistent in women, who showed lower risks of Alzheimer’s disease, depression, and anxiety. In men, the only reliable reduction was for anxiety.
In the brain imaging analyses, people exposed to rationing after birth had brains that looked about 0.39 years, or roughly five months, younger relative to their actual age than those of the comparison group. They also tended to have larger volumes in several deep brain structures, including the hippocampus, thalamus, and putamen, and lower contrast between gray and white matter across much of the cortex, a finding the authors say could reflect several different tissue changes and should be considered preliminary. Exposure only in the womb showed few associations with brain structure.
“These quasi-experimental findings suggest that early-life sugar restriction is associated with attenuated neurobiological aging and lower risks of dementia and psychiatric disorders, suggesting sugar intake as a potential modifiable factor of lifelong brain health,” study authors concluded.
The study contributes to the scientific understanding of the long-term consequences of early nutritional patterns. However, it should be noted that the end of sugar rationing coincided with broader post-war economic recovery, improved maternal healthcare, and changing infant feeding practices, all of which may have independently influenced brain development. Rationing of other foods also ended by July 1954, although consumption of those foods changed only slightly. Because of this, it remains uncertain how much of the observed differences are due to sugar alone.
Individual sugar intake was not measured; exposure was inferred from participants’ birth dates. Diagnoses of depression and anxiety relied partly on self-reports and primary care records, and participants grew up in a post-war, predominantly white British setting that may not reflect the experiences of children today. The authors say the findings need to be replicated in contemporary groups with detailed dietary information before informing clinical or public health recommendations.
The paper, “Early-life sugar rationing, brain aging, and long-term neurodegenerative and psychiatric health outcomes: a population-based natural experiment study,” was authored by Xingji Lian, Amei Chen, Xiaoyan Zhu, Yuyu Huang, Chongzhe Yang, Yan Huang, Meilong Ran, Longyan Yin, and Bing Zhang.