Just one alcoholic drink a day could lead to Alzheimer’s or Parkinson’s disease

OXFORD, United Kingdom — Just one small glass of wine each day could lead to the onset of Alzheimer’s or Parkinson’s disease, new research warns.

Specifically, researchers from the University of Oxford say consuming just seven units of alcohol a week – half the recommended maximum – fuels iron accumulation in the brain. They add that alcohol suppresses a hormone that controls the body’s absorption of the mineral, causing poorer brain performance.

“In the largest study to date, we found drinking greater than 7 units of alcohol weekly associated with iron accumulation in the brain. Higher brain iron in turn linked to poorer cognitive performance. Iron accumulation could underlie alcohol-related cognitive decline,” says lead author Dr. Anya Topiwala from the University of Oxford in a media release.

Dementia patients have been found to have higher levels of iron in some regions, including deep grey matter. The same pattern has been found in people with Parkinson’s — another brain disorder which causes tremors, stiffness, and loss of balance.

Studies have connected cognitive decline to the formation of rogue proteins known as amyloid beta which clump together and create harmful plaques which kill neurons. Iron from the blood is essential for brain functioning, but it needs to be tightly regulated.

Avoiding alcohol is the best way to stop iron build-up

The study of around 21,000 people adds to evidence that even moderate drinking can impact brain health. Drinking seven units or more of alcohol per week displayed a connection to markers of higher iron in the basal ganglia. These are groups of neurons that control motor movements, procedural learning, eye movement, cognition, emotion, and more. Iron accumulation in some areas of the brain also has a connection to poorer mental skills.

Participants from the UK Biobank (UKB) reported their own alcohol consumption and underwent MRI (magnetic resonance imaging) brain scans. Each person was between the ages of 40 and 69. Almost 7,000 participants also had their livers imaged to assess levels of systemic iron accumulation. The group also completed a series of simple tests to assess cognitive and motor function.

Although nearly three percent considered themselves as non-drinkers, average intake was around 18 units per week. That’s the equivalent to seven and a half cans of beer or six large glasses of wine.

“Never drinkers appeared to have the lowest levels of brain iron. This is in keeping with our earlier work indicating there may be no safe level of alcohol consumption for brain health,” researchers write in the journal PLOS Medicine.

“Moderate drinking is highly prevalent, so if elevated brain iron is confirmed as a mechanism by which alcohol leads to cognitive decline, there are opportunities for intervention on a population scale.”

Current drinking guidelines may not be strong enough

The number of dementia cases worldwide is expected to triple to more than 150 million by 2050. With no cure in sight there is an increasing focus on changing certain lifestyles habits — including drinking habits.

Dr. Topiwala points out there are drugs that reduce iron in the brain, known as chelators. They are already being investigated as potential Alzheimer’s and Parkinson’s treatments.

“Alcohol-related brain iron may be partially mediated by higher systemic iron levels, but it is likely there are additional mechanisms involved. Poorer executive function and fluid intelligence and slower reaction speeds were seen with markers of higher basal ganglia iron,” study authors write. “Brain iron accumulation is a possible mechanism for alcohol-related cognitive decline.”

Currently, the Centers for Disease Control and Prevention recommends that adult men of legal age consume no more than two drinks in a day. They recommend adult women limit themselves to one drink a day.

South West News Service writer Mark Waghorn contributed to this report.