Alcohol and Brain Size
Moderate alcohol consumption might be good for your heart, but new research suggests that it doesn’t appear to offer the same protective benefits for the brain. While moderate consumption doesn’t necessarily help your brain, regularly consuming more than two drinks a day can definitely harm it.
Habitual consumption of more than 14 alcoholic drinks per week actually causes the brain to shrink, according to the results of a study conducted by researchers at Wellesley College in Wellesley, Mass. The scientists found that the more alcohol an individual drinks on a regular basis, the lower his or her total brain volume.
For the study, the Wellesley researchers evaluated brain size and alcohol consumption patterns in more than 1,800 adults between the ages of 34 and 88 years. Magnetic resonance imaging (MRI) scans were performed and used to measure brain volume, a relatively reliable indicator of brain aging. Compared to those who abstained from alcohol, the subjects who habitually consumed more than 14 drinks per week had a 1.6 percent reduction in brain volume.
Although chronic drinking is detrimental to the entire brain, the cells of the hippocampus are especially vulnerable to damage from alcohol. The hippocampus is a small, curved structure in the brain that is vital to learning and memory formation. When the structure is surgically removed, a person’s ability to store most new experiences in memory is permanently lost. In individuals with advanced, debilitating Alzheimer’s dementia, the hippocampus is typically the first brain structure affected, and often the one that is most profoundly damaged by the disease.
In an animal study supported by the National Institutes of Health, scientists at Scripps Research Institute in San Diego found that chronic alcohol consumption dramatically reduced the number of new brain cells that form in the hippocampus. For the study, rhesus monkeys were allowed to voluntarily consume a sweetened beverage containing 6 percent alcohol during one-hour sessions, five days a week for five months. A control group of monkeys had equal access to a similar, alcohol-free beverage.
Analysis of the drinking monkeys’ brain tissue revealed that alcohol consumption significantly reduced new brain cell growth and proliferation in the hippocampus. Compared to the nondrinking monkeys, those consuming alcohol exhibited a 58 percent reduction in the number of new brain cells formed in the hippocampus and a 63 percent reduction in cell survival.
Based on the results of their study, the researchers concluded that chronic alcohol consumption not only causes existing cells of the hippocampus to die off, it also keeps new cells from forming. These findings have important implications for humans, since shrinkage of the hippocampus is known to coincide with declines in cognitive abilities, such as memory and learning, and ultimately dementia.
Although the hippocampus typically shrinks with age, the rate at which it grows smaller differs substantially among individuals. While regular physical activity and continued learning have been shown to enhance the size of the structure, chronic alcohol consumption appears to reduce it. In the earliest stages, loss of brain volume is associated with temporary, minor lapses in memory, such as forgetting a doctor’s appointment or the name of a casual acquaintance, according to the results of a study published in the medical journal Neurology.
The study included 500 adults aged 50 to 85 with no history of dementia. The subjects were asked about their experiences with occasional memory problems, such as having trouble thinking of the right word or forgetting events that had occurred in the previous hours or days. After evaluating subjects’ brains using MRI scans, researchers found that in individuals with occasional memory lapses, the hippocampus was measurably smaller than in subjects with no memory problems.
Protecting the hippocampus is especially important for people who have been diagnosed with early Alzheimer’s as well as for those who are at high risk for developing the disease. A study conducted by researchers at Oregon Health and Science University in Portland showed that having a large, healthy hippocampus might allow some older adults to compensate for Alzheimer’s related brain changes.
If you’re determined to keep your brain healthy and your mind sharp as you grow older, don’t stop exercising or learning new things. If you enjoy drinking alcohol, it’s important to continue to consume it in moderation.