Early life sugar restriction linked to lower Alzheimer's risk

A new study links early life sugar Alzheimer's risk to nutrition in the womb and the first years after birth. Researchers reported in npj Aging that people exposed to sugar rationing during the first 1,000 days after conception had a lower later-life risk of Alzheimer's disease and dementia.

The study, led by Xingji Lian and colleagues, used a historical policy change in the United Kingdom as a natural experiment. During World War II and the years after it, the UK tightly limited sugar, and the researchers said children under 2 did not receive a sugar ration.

That rationing ended in September 1953. According to the study, adult sugar intake in the UK nearly doubled after the policy ended, creating a sharp difference in early-life sugar exposure among people born in nearby years.

Does early life sugar affect Alzheimer's risk?

The researchers found an association, not proof that sugar restriction caused the lower disease rates. They reported that people whose first 1,000 days after conception fell under rationing had a 46% lower risk of Alzheimer's disease compared with those not exposed to rationing.

The same group also had a 27% lower risk of dementia from any cause, the authors reported. In psychiatric outcomes, the study found a 20% lower risk of anxiety and an 11% lower risk of depression, while it found no association with Parkinson's disease.

In this study, the first 1,000 days after conception covered development before birth and early childhood. The authors said some of the observed benefit may have begun before birth, based on comparisons between people rationed only in the womb, those rationed in the womb and early childhood, and those not rationed in either period.

How the rationing study was done

The team examined records for 60,394 people born from 1951 through 1956 who were enrolled in the UK Biobank, a large medical database. Researchers grouped participants by whether rationing affected fetal life only, fetal life plus early childhood, or neither period.

They then compared later medical records and self-reported health conditions across the groups. Because deliberately restricting an infant's diet for research would be unethical, the authors used the end of UK sugar rationing as a way to study real-world differences in early nutrition.

The researchers also analyzed MRI scans from 9,053 participants to look for brain differences. After accounting statistically for factors including genetics and family history, they found that people exposed to rationing had brains that appeared about 0.39 years younger than expected for their age, on average.

The study reported larger volumes in some brain regions, including the hippocampus and thalamus. The authors noted that those regions are involved in memory and other cognitive functions.

What the authors caution

The authors described the findings as quasi-experimental evidence that early-life sugar restriction is associated with slower neurobiological aging and lower risks of dementia and some psychiatric disorders. They did not present the results as definitive proof of cause and effect.

They also said the findings need to be repeated in contemporary groups with detailed information on early-life diet before they are used to shape clinical or public health advice. The study adds to evidence that nutrition very early in life may have health effects lasting decades, but the authors said confirmation in modern populations is still needed.

This story draws on original reporting from Medical Xpress.