Drinking Alcohol Could Disrupt Cells That Help Prevent Alzheimer's, Study Suggests

The way the body clears plaque globs linked to Alzheimer's disease could be disrupted by alcohol, according to a new study.

Past studies on whether drinking alcohol has a role to play in the development of Alzheimer's have had conflicting results, with some suggesting the substance is helpful while others indicating it is harmful. This new study in rats by a team at the University of Illinois Chicago supports the latter view.

It comes down to how the body tackles amyloid beta—a protein that clumps together as plaque in the brain—which evidence suggests may cause cognitive decline and lead to Alzheimer's disease.

The researchers set out to investigate whether alcohol affects microglial cells, which populate the central nervous system. They act as the first line of defense for the brain and spinal cord against damaged neurons and infections.

Scientists have investigated whether alcohol disrupts how the body clears away the protein linked to Alzheimer's disease. Getty Images

Microglial cells in the brain are believed to protect against Alzheimer's disease as they envelop and digest amyloid beta protein in a process called phagocytosis. Past research also indicates that these cells are inflamed by chronic exposure to alcohol.

To test their hypothesis, researchers exposed rat microglial cells to alcohol, inflammatory cells called proinflammatory cytokines, or alcohol and cytokines for a 24-hour period. The scientists then analyzed the cells to see if their gene expression had changed in each scenario, as well as if the cells could still attack amyloid beta.

The cells that encountered levels of alcohol comparable to those found in individuals who drink heavily or binge drink saw microglial phagocytosis hindered by around 15 percent after an hour. The findings were published in the Journal of Neuroinflammation. Further research is needed to determine whether this change continues in the long term.

Glial Amyloid Plaques
Glial cells (stained in orange) engulfing amyloid plaques (stained in green). Doug Feinstein

Dr. Douglas Feinstein, professor of anesthesiology in the University of Illinois at Chicago College of Medicine and lead author of the study explained that while the tests were performed in isolated cells, the results suggest that alcohol impedes the ability of microglia to keep the brain clear of amyloid beta and may contribute to the development of Alzheimer's disease, he said.

He told Newsweek: "There is a large literature supporting the idea that low amounts of alcohol can be beneficial; not only peripherally but in the brain. However, it might be prudent that if someone is at risk to develop AD, they should consider to reduce their alcohol intake; and certainly avoid binge or heavy drinking."

Dr. David Reynolds, chief scientific officer at Alzheimer's Research UK, told Newsweek it is hard to determine what level of alcohol consumption begins to affect the long-term health of the brain, but "there is strong evidence that regular, heavy drinking increases the risk of dementia."

"These are interesting findings, but as the researchers worked with cells from rats, we can't be sure how well this research reflects the effect of alcohol in people. The researchers exposed cells to a level of alcohol equivalent to very heavy binge drinking, and it's not clear whether this day-long procedure provides a useful insight into how cells in the brain are affected by alcohol over the course of someone's life." He emphasized that abstaining from excessive drinking is linked to better brain health.

Dr. James A. Hendrix, Alzheimer's Association director of global science initiatives, said the work was interesting, but stressed it was "very preliminary work" done in rats.

"We're still very far away from drawing any conclusions that would impact a person's day-to-day life," he told Newsweek, adding that "no one should start drinking alcohol as a means of lowering dementia risk."