Alzheimer's Markers Linked to High Sugar, High Fat Foods in Study on Mice

The combination of aging and eating foods high in fat and sugar has been linked to markers of Alzheimer's disease in a study.

Alzheimer's disease, the most common form of dementia, is the sixth leading cause of death in the U.S.. Around 5.7million Americans are living with the condition, and this figure is expected to spike to nearly 14million by 2020.

But the cause of the disease remains unknown. The chance of developing it raises as we grow older, and evidence suggests obesity caused by the diet could also be a risk factor, the authors of the new study published in the journal of Physiological Reports noted.

To investigate these theories, researchers at Brock University in Ontario, Canada, fed one group of mice a high-fat, high-sugar diet, while a control group continued with their normal food.

Scientists have found an association between high fat, high sugar foods which can cause obesity and Alzheimer's disease. Getty Images

After 13 weeks, the scientists measured the inflammation and stress levels in the hippocampus and prefrontal cortex of the mice. The hippocampus is linked to memory formation and spacial awareness, while the prefrontal cortex is the part of the brain in charge of complex cognitive behavior. Changes in these areas could therefore contribute to the development of Alzheimer's disease.

The researchers found the mice fed the high fat, high sugar diet had significantly higher markers of insulin resistance, inflammation, and cellular stress in the parts of the hippocampus believed to play a role in Alzheimer's disease. The prefrontal cortex, meanwhile, showed signs of insulin resistance, but no change in cellular stress or inflammation. Aging appears to also be a factor, as levels of inflammation in the control group also rose in the control group compared to baseline readings, according to the study.

The authors therefore believe the combination of a high fat, high sugar diet worsens the effects of aging on the brain in relation to Alzheimer's disease.

"These results add to our basic understanding of the pathways involved in the early progression of [Alzheimer's] pathogenesis and demonstrate the negative effects of a HFS diet on both the prefrontal cortex and hippocampal regions," the authors said in a statement.

As the study was carried out on mice, further research is needed to understand whether the results would be replicated in humans. But mice models give a useful insight into mechanisms in the body.

This is the latest study to suggest our diets could play a role in the onset of Alzheimer's. Earlier in June, a mouse study carried out by researchers at the University of Illinois Chicago found heavy drinking could affect how the brain clears plaque globs linked to Alzheimer's disease.

The paper published in the Journal of Neuroinflammation suggested microglial cells, which are found in the central nervous system, were impeded in their ability to clear amyloid beta by levels of alcohol comparable to a heavy drinking session.

Dr. Doug Brown, director of policy and research at the Alzheimer's Society charity, told Newsweek: "Although this study provides further evidence that a high-fat and high-sugar diet can lead to inflammation, which has been linked to the development of Alzheimer's Disease, it was performed in mice. What is true in mice might not be true in people, and more research is needed.

"What we do know is what is good for the heart is good for the head—a healthy diet and maintaining a healthy body weight can help to reduce risk of heart disease and dementia."

The study is "not as yet a game changer," he concluded.

This article has been updated with comment from Dr. Doug Brown.