Less sugar during early life linked to 46% lower Alzheimer’s risk

• Past studies show that an infant’s nutrition in the first days of life can affect their health later in life.
• A new study found that infants exposed to less sugar in their first 1,000 days of life experienced lower risks of developing Alzheimer’s disease and dementia from any cause as adults.
• Scientists also found that consuming less sugar during the first 1,000 days of life also led to a lower risk of depression and anxiety later in life.

Now, a new study published in the journal npj Aging says that infants exposed to less sugar in their first 1,000 days of life experienced lower risks of developing Alzheimer’s disease and dementia from any cause as adults.

At the study’s conclusion, researchers found that adults exposed to sugar restriction during the first 1,000 days of their lives had a 46% lower Alzheimer’s disease risk and 27% lower risk of developing all-cause dementia.

“This is, to our knowledge, the first human evidence that limiting sugar exposure in very early life is associated with substantial long-term protection against both neurodegenerative and psychiatric disorders.”
— Bing Zhang, PhD

“The risk reductions, especially for Alzheimer’s disease, are remarkably large. These findings highlight that dietary exposures during pregnancy and infancy may have lifelong impacts on brain health, and they reinforce the importance of current guidelines that recommend limiting added sugars early in life,” Zhang said.

Researchers also noted that participants exposed to sugar restriction also lowered their depression risk by 11% and anxiety risk by 20%.

Additionally, scientists observed that participants who were exposed to sugar rationing after birth had brains that were, on average, 0.39 years younger than their chronological age. These participants also had larger volumes in certain brain regions, including the hippocampus and thalamus.

“These imaging findings offer a plausible biological explanation for the reduced dementia risk,” Zhang explained.

“A younger-appearing brain and larger volumes in areas such as the hippocampus — a region critical for memory and one of the earliest affected in Alzheimer’s — suggest enhanced brain structural integrity and greater cognitive reserve. This indicates that early-life sugar restriction may promote optimal brain development and slow brain aging decades later.”
— Bing Zhang, PhD

“Alzheimer’s disease is a major and growing global health challenge, yet disease-modifying treatments remain limited and cannot halt progression,” Zhang continued.

“Preventing or delaying dementia through modifiable risk factors is therefore a public health priority. Identifying novel protective strategies, especially those that can be implemented early in life, offers a realistic pathway to reducing the future burden of dementia as populations age,” he added.

MNT spoke with Peter Gliebus, MD, chief of neurology and director of cognitive and behavioral neurology at Marcus Neuroscience Institute, part of Baptist Health South Florida, about this study, who commented that what makes this study interesting is that it takes advantage of a unique historical event, the end of sugar rationing in the U.K. in 1953.

“Because exposure to sugar was largely determined by when someone was born, it helps reduce some of the biases that often affect nutrition studies,” Gliebus, who was not involved in this study, continued.

“At the same time, I would be careful not to over-interpret the headline finding of a 46% lower risk of Alzheimer’s disease. That result was based on a relatively small number of Alzheimer’s cases, and the participants are still not at the ages when Alzheimer’s becomes most common. The findings related to depression and anxiety appear somewhat stronger,” he said.

While this study cannot tell us whether or not lowering sugar in adulthood would produce the same benefit, Dung Trinh, MD, an internist for the MemorialCare Medical Group and chief medical officer of the Healthy Brain Clinic in Irvine, CA, who was not involved in this study, said that there still may be benefits for reducing sugar.

“The goal should not be to eliminate all sugar, especially from nutritious foods such as whole fruit, but to limit excessive added sugars as part of a broader lifestyle that includes exercise, healthy sleep, and good control of blood pressure, cholesterol, and diabetes.”
— Dung Trinh, MD

MNT also spoke with Rehan Aziz, MD, DFAPA, geriatric psychiatrist at Hackensack Meridian Jersey Shore University Medical Center, and associate professor of psychiatry and neurology at Hackensack Meridian School of Medicine in New Jersey, who likewise was not involved in this study.

For the next steps in this research, Aziz said he would like to see whether sugar-restricted diets begun in midlife affect rates of late-life dementia, depression, and anxiety, since this study only speaks to the first 1,000 days and leaves the far more common question of adult intervention unanswered.

“I would also want to know whether some forms of sugar are more harmful than others, for example, added and liquid sugars versus those in whole foods, along with the threshold at which sugar or total carbohydrate intake becomes harmful, and the specific effects of high-fructose corn syrup and other ultra-processed carbohydrates, since those dominate the modern diet, on brain aging,” Aziz added.